The world is still grappling with the threat due to the emergence of the coronavirus disease-2019... more The world is still grappling with the threat due to the emergence of the coronavirus disease-2019 (COVID-19) caused by a new variant of coronavirus. The high transmission of the virus among humans has led to a pandemic and there is also emergence of mutant strain of virus (severe acute respiratory syndrome coronaviruses 2 Variant VOC 202012/01) within communities. With the uncertainties in the development, efficacy and reach of an effective vaccine among the masses, it has become a mammoth task for human beings to carry on with the dayto-day task and lifestyle. This has severely impacted the health-care services including the fertility treatments. The assisted reproductive technology (ART) services have accordingly molded itself to cater to patients. There are various guidelines and regulations introduced to provide fertility services on the basis of priority of the patients seeking treatments, keeping in compliance to the safety measures for the healthcare staffs and patients. On the other hand, couples wish to pursue their way to parenthood even in the testing times. Melatonin, a neurohormone, is a multipotent molecule associated with male and female reproduction and is being protectively involved in the various reproductive processes. It maintains the circadian rhythmicity of various hormones and has potentials in treating COVID-19 patients. Its use in IVF procedures can be protective and effective measure to deal with the uncertainties of time. Its immune enhancing role can be utilized in fulfilling the patients’ health and achieving fertility goals contributing to the success of ART.
Extensive research has unraveled a niche for melatonin that is of great significance for the fema... more Extensive research has unraveled a niche for melatonin that is of great significance for the female reproductive physiology. The potency of melatonin as an antioxidant, anti-inflammatory, and anti-apoptotic agent is being utilized to benefit female reproductive anomalies. Melatonin receptors have been localized in the Supra Chaismatic Nucleus (SCN), pars tuberalis (PT), and the gonads suggesting the regulation of reproduction by melatonin not only at a higher level but also on the gonads through complex interrelated mechanisms. Melatonin secreted by the pineal gland acts on the hypothalamus to regulate gonadotropin-releasing hormone and subsequently gonadotropin (FSH/LH) release from the PT. However, the de novo synthesis of this indoleamine reported in the gonads gave rise to the idea of a more localized action. The mammalian ovary has all the molecular machinery required for the biosynthesis of melatonin and interestingly concentration of melatonin in the follicular fluid of pre-ovulatory follicles is much higher than circulatory melatonin even in humans. This locally produced melatonin has been shown to modulate various pathways governing ovarian steroidogenesis. Further, melatonin and its receptors play a significant role in antioxidant defense mechanism of ovary for follicular growth and maturation. Exposure to stress strongly influences hypothalamic-pituitary-adrenal axis and elevated glucocorticoid levels suppress various ovarian functions including implantation thereby pregnancy. Melatonin acts antagonistically with glucocorticoids, making it crucial for the management of the female reproductive functions/dysfunctions. Usage of melatonin during in vitro fertilization (IVF) procedures has been found to improve oocyte quality, survival, and fecundity. Therefore, in future, melatonin can be implicated as preferable therapeutic especially in IVF and assisted reproductive techniques.
Part 1 Structure: structure and function in the parietal-pineal complex of the lizard, Koji Ohshi... more Part 1 Structure: structure and function in the parietal-pineal complex of the lizard, Koji Ohshima comparative fine structural organization and histochemistry of the pineal organ, B. Vigh et al pineal synaptic ribbons - new from the retina, L. Voillrath and I. Spiwoks-Becker the structure of the pineal gland in domestic animals, V. Ramkrishna and Ashok Pawar fish pineal - structure, function and regulation, B.B.P. Gupta and Y. Premabati. Part 2 Functions: melatonin - an ubiquitous and evolutionary hormone, Ario Conti et al gastrointestinal melatonin - a Cinderella story of melatonin research, G.A. Bubenik melatonin from the past into the future - our own experience, Andrzej Lewinski et al rhythmic pineal melatonin production in birds, B. Mess and V. Csernus melatonin in the anuran amphibian larva and its reciprocal interactions with the thyroid gland, M.L. Wright the pineal gland and melatonin in domestic animals, N.H. Mohan bimodal effects of melatonin on the inflammatory reaction in young chickens, K. Skwarlo-Sonta et al pineal and glucoregulation in vertebrates with special emphasis on aves, A.V. Ramachandran pineal and lateral eyes in photo-thermal induced gonadal response in Indian catfish, Bechan Lal et al pineal gland and melatonin during gestation and foetal/neonatal development, C. Haldar and K.S. Bishnupuri pineal in the regulation of avian reproduction, S.K. Maitra et al re-entrainment of the mammalian circadian rhythm by melatonin, M. Singaravel et al pineal regulated adrenal-gonadal function in birds, C.C. Sudhakumari and C. Haldar. Part 3 Molecular mechanisms: application of the chromatographic technique to the analysis of melatonin and its related indoleamines, T.Harumi and S.R. Pandi-Perumal neuropeptidey, an important modulator of the noradrenergic input of the mammalian pineal gland, V. Simonneaux and C. Ribelayga neurochemistry and biology of melatonin oxidation, R. Hardeland and B. Poeggeler is NT the rate-limiting enzyme in melatonin synthesis?, Jimo Borjigin et al. Part 4 Clinical aspects: pinealities/uveitis - clinical and experimental perspectives, Carolyn M. Kalsow melatonin - psychiatric perspectives, C. Pacchierotti et al chronobiological, clinical and pharmacological aspects of melatonin in human circadian rhythm dysfunction, J.E. Nagtegaal et al pharmacological effects of melatonin in ion-channels, G. Panyi et al melatonin effects on cytoskeletal organization - implications for brain function and disease, G. Benitex-King et al slow wave sleep distribution and REM sleep eye movement density in delayed sleep phase syndrome on and off melatonin treatment, L. Kayumov et al apoptosis, cancer, immunity and melatonin, C. Haldar dual role of melatonin in humans - a hormone and a chronobiotic drug, B. Claustrat et al.
The present study provides evidence, for the first time, of a role of the pineal gland in the pro... more The present study provides evidence, for the first time, of a role of the pineal gland in the proliferation of CFU-GM under the influence of different cytokines. The degree of colony formation in different cytokine groups was evaluated after 24 h, 3, 7 and 10 days. The colony growth in the present type of bone marrow cell cultures slows after the 10th day and ceases after the 14th day of incubation. The results show that rGM-CSF and the combination of rGM-CSF with rIl-3 and with rEPO stimulate the colony formation of granulocytes and macrophages. A 50% general reduction in the colony number was noted in the pinealectomy group. Their pattern of response to the different cytokines was similar to that of the intact group. It is suggested that the pineal activity has a physiological role in important aspects of host defence mechanisms, such as the proliferation of CFU-GM.
Ever‐increasing occurrence of plastic‐manufacturing industries leads to environmental pollution t... more Ever‐increasing occurrence of plastic‐manufacturing industries leads to environmental pollution that has been associated with declined human health and increased incidence of compromised reproductive health. Female subfertility/infertility is a complex phenomenon and environmental toxicants as well as lifestyle factors have a crucial role to play. Bisphenol S (BPS) was believed to be a “safer” replacement of bisphenol A (BPA) but recent data documented its neurotoxic, hepatotoxic, nephrotoxic, and reprotoxic attributes. Hence based on the scarcity of reports, we investigated molecular insights into BPS‐induced ovarian dysfunction and protective actions of melatonin against it in adult golden hamsters, Mesocricetus auratus. Hamsters were administered with melatonin (3 mg/kg BW i.p. alternate days) and BPS (150 mg/kg BW orally every day) for 28 days. BPS treatment disrupted hypothalamo–pituitary–ovarian (HPO) axis as evident by reduced gonadotropins such as luteinizing hormone (LH) and follicle‐stimulating hormone (FSH), ovarian steroids such as estradiol (E2) and progesterone (P4), thyroid hormones namely triiodothyronine (T3) and thyroxine (T4) and melatonin levels along with their respective receptors (ERα, TRα, and MT‐1) thereby reducing ovarian folliculogenesis. BPS exposure also led to ovarian oxidative stress/inflammation by increasing reactive oxygen species and metabolic disturbances. However, melatonin supplementation to BPS restored ovarian folliculogenesis/steroidogenesis as indicated by increased number of growing follicles/corpora lutea and E2/P4 levels. Further, melatonin also stimulated key redox/survival markers such as silent information regulator of transcript‐1 (SIRT‐1), forkhead box O‐1 (FOXO‐1), nuclear factor E2‐related factor‐2 (Nrf2), and phosphoinositide 3‐kinase/protein kinase B (PI3K/pAkt) expressions along with enhanced ovarian antioxidant capacity. Moreover, melatonin treatment reduced inflammatory load including ovarian nuclear factor kappa‐B (NFĸB), cyclooxygenase‐2 (COX‐2), and inducible nitric oxide synthase (iNOS) expressions, serum tumor necrosis factor α (TNFα), C‐reactive protein (CRP) and nitrite–nitrate levels as well as upregulated ovarian insulin receptor (IR), glucose uptake transporter‐4 (GLUT‐4), connexin‐43, and proliferating cell nuclear antigen (PCNA) expressions in ovary thereby ameliorating inflammatory and metabolic alterations due to BPS. In conclusion, we found severe deleterious impact of BPS on ovary while melatonin treatment protected ovarian physiology from these detrimental changes suggesting it to be a potential preemptive candidate against environmental toxicant‐compromised female reproductive health.
Journal of Endocrinology and Reproduction, Jun 1, 2012
Avian immunology is a fascinating and growing field. Ecologists are now taking an interest in mea... more Avian immunology is a fascinating and growing field. Ecologists are now taking an interest in measuring immune-competence and determining its importance as a heritable trait for the survival of the wild species. Seasonally breeding animals encounter different environmental challenges throughout the year. In order to survive in specific environments these animals have developed various strategies that help them to find food, protect themselves from the tough environments, and also reproduce accordingly. Indeed, wild birds are continually challenged with different natural stressors such as shortage of food (during winter and rainy season), lack of water during summer, predator pressure in social system, sudden change in weather, season-bound diseases, infection (like avian influenza), etc. Only a few ecological studies have analyzed the stress and general immunity in wild birds that might have a link with the anti-stress hormone melatonin. Therefore, approaches improving our understanding of the stress-induced immune depression and their interrelationship in birds are most desirable. Unfortunately, our knowledge of the immune system has advanced at a much faster pace for mammals while immunology of wild birds received less attention. The purpose of this review is to bring together the current knowledge on the biological effects of melatonin on avian immune defense with special emphasis on new immerging area of neuro-immuno-endocrinology i.e., eco-immunology.
Journal of Endocrinology and Reproduction, Dec 1, 2001
Birds in general have not been frequently examined for the immunological influences of melatonin ... more Birds in general have not been frequently examined for the immunological influences of melatonin or pineal gland, as it has been potentially noted with the mammals including human being. There are only few reports suggesting that melatonin may play some role in the development and function of the immune system in the birds. The diurnal pattern of the melatonin synthesis is the same In almost all vertebrate groups so far examined, though differences exist in structure or anatomy of the pineal gland and seasonal variation in the peripheral melatonin level. Since functional relationship between neuroendocrine pineal gland and immune systems appears as to be diverse, it is logical that immunomodulatory effects of melatonin may be different in different seasons. The seasonal variation In melatonin level has been proved to improve the status of Immunity in seasonal tropical birds to bear the natural challenges. The level of peripheral melatonin minimizes some inflammatory diseases and sudden death syndrome in some poultry birds. The effect of melatonin also depends upon the phases of the inflammatory reaction/process. Pinealectomy in birds demonstrated functional interrelationship between the development of pineal gland, ontogeny of the melatonin secretion and immune system and/or neuroendocrine network. Bursectomy could influence the diurnal rhythm of melatonin and may abolish the effect of immunization on serum melatonin level. Specificities of avian immune system may be, however, very useful for understanding numerous phylogenetic and evolutionary mysteries. In this way a reciprocal functional connection between the avain immune system and the pineal gland seems to exist, but the mechanisms involved in maintaining the immune status by melatonin in avain group Is still not clear and needs to be elucidated.
Effects of melatonin (aMT) and 5-methoxytryptamine (MT) were studied on the testicular activity c... more Effects of melatonin (aMT) and 5-methoxytryptamine (MT) were studied on the testicular activity cycle of the fresh-water snake, Natrix piscator. The subcutaneous implantation and the injections (morning as well as evening) of these two methoxyindoles prevented testicular recrudescence, retarded the testicular active phase, and accelerated the rate of regression of testes, while having no effect on the inactive testes. Contrary to this, these two compounds increased the pineal gland weight during different reproductive phases. These results revealed that both aMT and MT, whether they were continuously released through silastic capsule implants or administered through daily periodic injections, produced inhibitory effects on the testicular function.
Abstract Caprine immune system has largely been neglected by ruminant researchers despite of its ... more Abstract Caprine immune system has largely been neglected by ruminant researchers despite of its high economic importance in bioindustry. We made an attempt to note the annual/seasonal and gender dependent variation in immune status of the domestic goat, Capra hircus , Jamunapari breed and correlated with the concentration of peripheral gonadal hormones (testosterone, 17β-estradiol) and melatonin. Based on the data of general immune parameters such as total leukocyte count (TLC) and percent lymphocyte count (%LC) along with blastogenic response of splenocytes in terms of percent stimulation ratio (%SR), we found an annual variation in immune status of male, female and castrated male goats in a gender dependent manner. Female goats showed higher immune parameters than that of castrated as well as intact male goats. Testosterone in intact male goats was high throughout the year, which might be responsible for low immune status. However, in castrated male goats, plasma testosterone was undetectable and presented an immune status equivalent to that of female goats. We observed a high immune status during the winter season in all the groups of goats, which might be due to high circulatory concentration and longer duration of melatonin induced by short days. Being released by circulating lymphocytes, the concentration of interleukin-2 (IL-2) in blood plasma, showed an annual and seasonal variation being higher in female than castrated and intact male goats throughout the year, having a similar trend in plasma melatonin concentration. The higher immune status in female goats during the winter months might have helped them to overcome the winter bound stress, i.e. low temperature. Therefore, we may propose that testosterone acts as an immunosupressor while melatonin as an immunostimulator for goats as it showed a positive correlation with immune parameters noted.
Journal of Endocrinology and Reproduction, May 30, 2017
Crosstalk between the neuro-endocrine axis and immune cells is documented in many laboratory and ... more Crosstalk between the neuro-endocrine axis and immune cells is documented in many laboratory and clinical studies. The pineal gland and its hormone melatonin play a central role in this network by positively regulating immune cell proliferation and differentiation via influencing the synthesis of immunomodulatory molecules. However, the pineal-thymus interaction in modulating their bi-directional communication remains elusive. In the present study we investigated the effect of pineal-thymus interaction on the structure and functional status of lymphoid tissues (i.e., spleen and lymph nodes) in a tropical seasonal breeder, F. pennanti. We observed that pinealectomy severely compromised the immune status of the squirrels. Besides pinealectomy, simultaneous ablation of pineal and thymus gland, further resulted in atrophy of the lymphoid tissues along with reduced total leucocyte and lymphocyte count. Exogenous melatonin administration improved the total leucocyte and lymphocyte count and restored T cell dependent immune responses and lymphoid tissue architecture in pinealectomized (Px) group. Our observations suggest that suppression of endogenous melatonin in Px group decreased the efficiency of the immune system probably by modulating the production of thymic factors, which becomes even severe with simultaneous ablation of the thymus and pineal gland, resulting in declined immune responsiveness. Thus, it can be inferred that the pineal melatonin and its interaction with thymus plays an important role in regulation of immune status of the squirrels.
Journal of Endocrinology and Reproduction, Nov 3, 2016
As a transducer of the environmental factors the pineal gland, together with the metabolically ac... more As a transducer of the environmental factors the pineal gland, together with the metabolically active thyroid gland, plays a major role in control of reproduction during different times of the year, in response to the changing environmental conditions of the tropical zone unlike in the temperate zone. Our avian model P. asiatica is a long day breeder. It is reproductively active during summer and quiescent during winter months. In this study we investigated the role of thyroid gland super-imposed by melatonin in the regulation of the annual male reproduction in this bird. The metabolically active thyroid gland presented a functional parallelism with the testicular activity suggesting that thyroid hormone is essential for reproductive activity and related metabolic energy for avian species. Our data also suggest an inhibitory effect of melatonin on thyroid gland function [weight, thyroxine (T3/ T4) level and thymidine kinase activity, THK] both during active and inactive phases of the reproductive cycle. However, this inhibitory effect was less evident during the active phase. The low level of melatonin during the reproductively active phase might be due to long days of summer which prevented the birds from being hyperthyroidic. Therefore, we suggest that the level of melatonin serves as a physiological check to control the seasonal reproductive activities of gonads and thyroid which synergistically play most important physiological roles in energy metabolism of these seasonally breeding bird P. asiatica .
The world is still grappling with the threat due to the emergence of the coronavirus disease-2019... more The world is still grappling with the threat due to the emergence of the coronavirus disease-2019 (COVID-19) caused by a new variant of coronavirus. The high transmission of the virus among humans has led to a pandemic and there is also emergence of mutant strain of virus (severe acute respiratory syndrome coronaviruses 2 Variant VOC 202012/01) within communities. With the uncertainties in the development, efficacy and reach of an effective vaccine among the masses, it has become a mammoth task for human beings to carry on with the dayto-day task and lifestyle. This has severely impacted the health-care services including the fertility treatments. The assisted reproductive technology (ART) services have accordingly molded itself to cater to patients. There are various guidelines and regulations introduced to provide fertility services on the basis of priority of the patients seeking treatments, keeping in compliance to the safety measures for the healthcare staffs and patients. On the other hand, couples wish to pursue their way to parenthood even in the testing times. Melatonin, a neurohormone, is a multipotent molecule associated with male and female reproduction and is being protectively involved in the various reproductive processes. It maintains the circadian rhythmicity of various hormones and has potentials in treating COVID-19 patients. Its use in IVF procedures can be protective and effective measure to deal with the uncertainties of time. Its immune enhancing role can be utilized in fulfilling the patients’ health and achieving fertility goals contributing to the success of ART.
Extensive research has unraveled a niche for melatonin that is of great significance for the fema... more Extensive research has unraveled a niche for melatonin that is of great significance for the female reproductive physiology. The potency of melatonin as an antioxidant, anti-inflammatory, and anti-apoptotic agent is being utilized to benefit female reproductive anomalies. Melatonin receptors have been localized in the Supra Chaismatic Nucleus (SCN), pars tuberalis (PT), and the gonads suggesting the regulation of reproduction by melatonin not only at a higher level but also on the gonads through complex interrelated mechanisms. Melatonin secreted by the pineal gland acts on the hypothalamus to regulate gonadotropin-releasing hormone and subsequently gonadotropin (FSH/LH) release from the PT. However, the de novo synthesis of this indoleamine reported in the gonads gave rise to the idea of a more localized action. The mammalian ovary has all the molecular machinery required for the biosynthesis of melatonin and interestingly concentration of melatonin in the follicular fluid of pre-ovulatory follicles is much higher than circulatory melatonin even in humans. This locally produced melatonin has been shown to modulate various pathways governing ovarian steroidogenesis. Further, melatonin and its receptors play a significant role in antioxidant defense mechanism of ovary for follicular growth and maturation. Exposure to stress strongly influences hypothalamic-pituitary-adrenal axis and elevated glucocorticoid levels suppress various ovarian functions including implantation thereby pregnancy. Melatonin acts antagonistically with glucocorticoids, making it crucial for the management of the female reproductive functions/dysfunctions. Usage of melatonin during in vitro fertilization (IVF) procedures has been found to improve oocyte quality, survival, and fecundity. Therefore, in future, melatonin can be implicated as preferable therapeutic especially in IVF and assisted reproductive techniques.
Part 1 Structure: structure and function in the parietal-pineal complex of the lizard, Koji Ohshi... more Part 1 Structure: structure and function in the parietal-pineal complex of the lizard, Koji Ohshima comparative fine structural organization and histochemistry of the pineal organ, B. Vigh et al pineal synaptic ribbons - new from the retina, L. Voillrath and I. Spiwoks-Becker the structure of the pineal gland in domestic animals, V. Ramkrishna and Ashok Pawar fish pineal - structure, function and regulation, B.B.P. Gupta and Y. Premabati. Part 2 Functions: melatonin - an ubiquitous and evolutionary hormone, Ario Conti et al gastrointestinal melatonin - a Cinderella story of melatonin research, G.A. Bubenik melatonin from the past into the future - our own experience, Andrzej Lewinski et al rhythmic pineal melatonin production in birds, B. Mess and V. Csernus melatonin in the anuran amphibian larva and its reciprocal interactions with the thyroid gland, M.L. Wright the pineal gland and melatonin in domestic animals, N.H. Mohan bimodal effects of melatonin on the inflammatory reaction in young chickens, K. Skwarlo-Sonta et al pineal and glucoregulation in vertebrates with special emphasis on aves, A.V. Ramachandran pineal and lateral eyes in photo-thermal induced gonadal response in Indian catfish, Bechan Lal et al pineal gland and melatonin during gestation and foetal/neonatal development, C. Haldar and K.S. Bishnupuri pineal in the regulation of avian reproduction, S.K. Maitra et al re-entrainment of the mammalian circadian rhythm by melatonin, M. Singaravel et al pineal regulated adrenal-gonadal function in birds, C.C. Sudhakumari and C. Haldar. Part 3 Molecular mechanisms: application of the chromatographic technique to the analysis of melatonin and its related indoleamines, T.Harumi and S.R. Pandi-Perumal neuropeptidey, an important modulator of the noradrenergic input of the mammalian pineal gland, V. Simonneaux and C. Ribelayga neurochemistry and biology of melatonin oxidation, R. Hardeland and B. Poeggeler is NT the rate-limiting enzyme in melatonin synthesis?, Jimo Borjigin et al. Part 4 Clinical aspects: pinealities/uveitis - clinical and experimental perspectives, Carolyn M. Kalsow melatonin - psychiatric perspectives, C. Pacchierotti et al chronobiological, clinical and pharmacological aspects of melatonin in human circadian rhythm dysfunction, J.E. Nagtegaal et al pharmacological effects of melatonin in ion-channels, G. Panyi et al melatonin effects on cytoskeletal organization - implications for brain function and disease, G. Benitex-King et al slow wave sleep distribution and REM sleep eye movement density in delayed sleep phase syndrome on and off melatonin treatment, L. Kayumov et al apoptosis, cancer, immunity and melatonin, C. Haldar dual role of melatonin in humans - a hormone and a chronobiotic drug, B. Claustrat et al.
The present study provides evidence, for the first time, of a role of the pineal gland in the pro... more The present study provides evidence, for the first time, of a role of the pineal gland in the proliferation of CFU-GM under the influence of different cytokines. The degree of colony formation in different cytokine groups was evaluated after 24 h, 3, 7 and 10 days. The colony growth in the present type of bone marrow cell cultures slows after the 10th day and ceases after the 14th day of incubation. The results show that rGM-CSF and the combination of rGM-CSF with rIl-3 and with rEPO stimulate the colony formation of granulocytes and macrophages. A 50% general reduction in the colony number was noted in the pinealectomy group. Their pattern of response to the different cytokines was similar to that of the intact group. It is suggested that the pineal activity has a physiological role in important aspects of host defence mechanisms, such as the proliferation of CFU-GM.
Ever‐increasing occurrence of plastic‐manufacturing industries leads to environmental pollution t... more Ever‐increasing occurrence of plastic‐manufacturing industries leads to environmental pollution that has been associated with declined human health and increased incidence of compromised reproductive health. Female subfertility/infertility is a complex phenomenon and environmental toxicants as well as lifestyle factors have a crucial role to play. Bisphenol S (BPS) was believed to be a “safer” replacement of bisphenol A (BPA) but recent data documented its neurotoxic, hepatotoxic, nephrotoxic, and reprotoxic attributes. Hence based on the scarcity of reports, we investigated molecular insights into BPS‐induced ovarian dysfunction and protective actions of melatonin against it in adult golden hamsters, Mesocricetus auratus. Hamsters were administered with melatonin (3 mg/kg BW i.p. alternate days) and BPS (150 mg/kg BW orally every day) for 28 days. BPS treatment disrupted hypothalamo–pituitary–ovarian (HPO) axis as evident by reduced gonadotropins such as luteinizing hormone (LH) and follicle‐stimulating hormone (FSH), ovarian steroids such as estradiol (E2) and progesterone (P4), thyroid hormones namely triiodothyronine (T3) and thyroxine (T4) and melatonin levels along with their respective receptors (ERα, TRα, and MT‐1) thereby reducing ovarian folliculogenesis. BPS exposure also led to ovarian oxidative stress/inflammation by increasing reactive oxygen species and metabolic disturbances. However, melatonin supplementation to BPS restored ovarian folliculogenesis/steroidogenesis as indicated by increased number of growing follicles/corpora lutea and E2/P4 levels. Further, melatonin also stimulated key redox/survival markers such as silent information regulator of transcript‐1 (SIRT‐1), forkhead box O‐1 (FOXO‐1), nuclear factor E2‐related factor‐2 (Nrf2), and phosphoinositide 3‐kinase/protein kinase B (PI3K/pAkt) expressions along with enhanced ovarian antioxidant capacity. Moreover, melatonin treatment reduced inflammatory load including ovarian nuclear factor kappa‐B (NFĸB), cyclooxygenase‐2 (COX‐2), and inducible nitric oxide synthase (iNOS) expressions, serum tumor necrosis factor α (TNFα), C‐reactive protein (CRP) and nitrite–nitrate levels as well as upregulated ovarian insulin receptor (IR), glucose uptake transporter‐4 (GLUT‐4), connexin‐43, and proliferating cell nuclear antigen (PCNA) expressions in ovary thereby ameliorating inflammatory and metabolic alterations due to BPS. In conclusion, we found severe deleterious impact of BPS on ovary while melatonin treatment protected ovarian physiology from these detrimental changes suggesting it to be a potential preemptive candidate against environmental toxicant‐compromised female reproductive health.
Journal of Endocrinology and Reproduction, Jun 1, 2012
Avian immunology is a fascinating and growing field. Ecologists are now taking an interest in mea... more Avian immunology is a fascinating and growing field. Ecologists are now taking an interest in measuring immune-competence and determining its importance as a heritable trait for the survival of the wild species. Seasonally breeding animals encounter different environmental challenges throughout the year. In order to survive in specific environments these animals have developed various strategies that help them to find food, protect themselves from the tough environments, and also reproduce accordingly. Indeed, wild birds are continually challenged with different natural stressors such as shortage of food (during winter and rainy season), lack of water during summer, predator pressure in social system, sudden change in weather, season-bound diseases, infection (like avian influenza), etc. Only a few ecological studies have analyzed the stress and general immunity in wild birds that might have a link with the anti-stress hormone melatonin. Therefore, approaches improving our understanding of the stress-induced immune depression and their interrelationship in birds are most desirable. Unfortunately, our knowledge of the immune system has advanced at a much faster pace for mammals while immunology of wild birds received less attention. The purpose of this review is to bring together the current knowledge on the biological effects of melatonin on avian immune defense with special emphasis on new immerging area of neuro-immuno-endocrinology i.e., eco-immunology.
Journal of Endocrinology and Reproduction, Dec 1, 2001
Birds in general have not been frequently examined for the immunological influences of melatonin ... more Birds in general have not been frequently examined for the immunological influences of melatonin or pineal gland, as it has been potentially noted with the mammals including human being. There are only few reports suggesting that melatonin may play some role in the development and function of the immune system in the birds. The diurnal pattern of the melatonin synthesis is the same In almost all vertebrate groups so far examined, though differences exist in structure or anatomy of the pineal gland and seasonal variation in the peripheral melatonin level. Since functional relationship between neuroendocrine pineal gland and immune systems appears as to be diverse, it is logical that immunomodulatory effects of melatonin may be different in different seasons. The seasonal variation In melatonin level has been proved to improve the status of Immunity in seasonal tropical birds to bear the natural challenges. The level of peripheral melatonin minimizes some inflammatory diseases and sudden death syndrome in some poultry birds. The effect of melatonin also depends upon the phases of the inflammatory reaction/process. Pinealectomy in birds demonstrated functional interrelationship between the development of pineal gland, ontogeny of the melatonin secretion and immune system and/or neuroendocrine network. Bursectomy could influence the diurnal rhythm of melatonin and may abolish the effect of immunization on serum melatonin level. Specificities of avian immune system may be, however, very useful for understanding numerous phylogenetic and evolutionary mysteries. In this way a reciprocal functional connection between the avain immune system and the pineal gland seems to exist, but the mechanisms involved in maintaining the immune status by melatonin in avain group Is still not clear and needs to be elucidated.
Effects of melatonin (aMT) and 5-methoxytryptamine (MT) were studied on the testicular activity c... more Effects of melatonin (aMT) and 5-methoxytryptamine (MT) were studied on the testicular activity cycle of the fresh-water snake, Natrix piscator. The subcutaneous implantation and the injections (morning as well as evening) of these two methoxyindoles prevented testicular recrudescence, retarded the testicular active phase, and accelerated the rate of regression of testes, while having no effect on the inactive testes. Contrary to this, these two compounds increased the pineal gland weight during different reproductive phases. These results revealed that both aMT and MT, whether they were continuously released through silastic capsule implants or administered through daily periodic injections, produced inhibitory effects on the testicular function.
Abstract Caprine immune system has largely been neglected by ruminant researchers despite of its ... more Abstract Caprine immune system has largely been neglected by ruminant researchers despite of its high economic importance in bioindustry. We made an attempt to note the annual/seasonal and gender dependent variation in immune status of the domestic goat, Capra hircus , Jamunapari breed and correlated with the concentration of peripheral gonadal hormones (testosterone, 17β-estradiol) and melatonin. Based on the data of general immune parameters such as total leukocyte count (TLC) and percent lymphocyte count (%LC) along with blastogenic response of splenocytes in terms of percent stimulation ratio (%SR), we found an annual variation in immune status of male, female and castrated male goats in a gender dependent manner. Female goats showed higher immune parameters than that of castrated as well as intact male goats. Testosterone in intact male goats was high throughout the year, which might be responsible for low immune status. However, in castrated male goats, plasma testosterone was undetectable and presented an immune status equivalent to that of female goats. We observed a high immune status during the winter season in all the groups of goats, which might be due to high circulatory concentration and longer duration of melatonin induced by short days. Being released by circulating lymphocytes, the concentration of interleukin-2 (IL-2) in blood plasma, showed an annual and seasonal variation being higher in female than castrated and intact male goats throughout the year, having a similar trend in plasma melatonin concentration. The higher immune status in female goats during the winter months might have helped them to overcome the winter bound stress, i.e. low temperature. Therefore, we may propose that testosterone acts as an immunosupressor while melatonin as an immunostimulator for goats as it showed a positive correlation with immune parameters noted.
Journal of Endocrinology and Reproduction, May 30, 2017
Crosstalk between the neuro-endocrine axis and immune cells is documented in many laboratory and ... more Crosstalk between the neuro-endocrine axis and immune cells is documented in many laboratory and clinical studies. The pineal gland and its hormone melatonin play a central role in this network by positively regulating immune cell proliferation and differentiation via influencing the synthesis of immunomodulatory molecules. However, the pineal-thymus interaction in modulating their bi-directional communication remains elusive. In the present study we investigated the effect of pineal-thymus interaction on the structure and functional status of lymphoid tissues (i.e., spleen and lymph nodes) in a tropical seasonal breeder, F. pennanti. We observed that pinealectomy severely compromised the immune status of the squirrels. Besides pinealectomy, simultaneous ablation of pineal and thymus gland, further resulted in atrophy of the lymphoid tissues along with reduced total leucocyte and lymphocyte count. Exogenous melatonin administration improved the total leucocyte and lymphocyte count and restored T cell dependent immune responses and lymphoid tissue architecture in pinealectomized (Px) group. Our observations suggest that suppression of endogenous melatonin in Px group decreased the efficiency of the immune system probably by modulating the production of thymic factors, which becomes even severe with simultaneous ablation of the thymus and pineal gland, resulting in declined immune responsiveness. Thus, it can be inferred that the pineal melatonin and its interaction with thymus plays an important role in regulation of immune status of the squirrels.
Journal of Endocrinology and Reproduction, Nov 3, 2016
As a transducer of the environmental factors the pineal gland, together with the metabolically ac... more As a transducer of the environmental factors the pineal gland, together with the metabolically active thyroid gland, plays a major role in control of reproduction during different times of the year, in response to the changing environmental conditions of the tropical zone unlike in the temperate zone. Our avian model P. asiatica is a long day breeder. It is reproductively active during summer and quiescent during winter months. In this study we investigated the role of thyroid gland super-imposed by melatonin in the regulation of the annual male reproduction in this bird. The metabolically active thyroid gland presented a functional parallelism with the testicular activity suggesting that thyroid hormone is essential for reproductive activity and related metabolic energy for avian species. Our data also suggest an inhibitory effect of melatonin on thyroid gland function [weight, thyroxine (T3/ T4) level and thymidine kinase activity, THK] both during active and inactive phases of the reproductive cycle. However, this inhibitory effect was less evident during the active phase. The low level of melatonin during the reproductively active phase might be due to long days of summer which prevented the birds from being hyperthyroidic. Therefore, we suggest that the level of melatonin serves as a physiological check to control the seasonal reproductive activities of gonads and thyroid which synergistically play most important physiological roles in energy metabolism of these seasonally breeding bird P. asiatica .
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Papers by Chandana Haldar