Human diet contains a series of bioactive vegetal compounds that can improve human health. Among ... more Human diet contains a series of bioactive vegetal compounds that can improve human health. Among these, there has been a special interest for phytoestrogens. This article reviews the evidence about the potential benefits of phytoestrogens for human health. Forty eight manuscripts were selected for their study design and relevance to human health. The cell growth inhibitory effects of phytoestrogens and their implication in breast cancer are reviewed. Also the effects of these compounds on serum lipid levels and the effectiveness of a phytoestrogen derivate, ipriflavone, on the prevention of osteoporosis are analyzed. Although these compounds have a great potential for improving health, there is still not enough evidence to recommend the routine use of phytoestrogens.
Advances in experimental medicine and biology, 2008
A stable cyclized 9-mer peptide (cP) containing the active site of alpha-alpha fetoprotein (alpha... more A stable cyclized 9-mer peptide (cP) containing the active site of alpha-alpha fetoprotein (alphaFP) has been shown to be effective for prevention of estrogen-stimulated tumor cell proliferation in culture or of xenographt growth in immunodeficient mice. cP does not block 17beta-estradiol (E2) binding to its receptors, but rather appears to interfere with intracellular processing of the signal that supports growth. To obtain insight on that mechanism we studied the effect of cP on the proliferation of MCF-7 cells in culture. Proliferation in the presence of 2 microM E2 is decreased up to 40% upon addition of 2 microg ml(-1) cP to the medium; the presence of cP did not increase cell death, cP reduced also the proliferation of estrogen-dependent ZR75-1 cells but had no effect on autonomous MDA-MB-231 cells, cP did not modify the number of binding sites for labeled E2 or affected cell death. We detected increased nuclear p21Cip1 immunoreactivity after cP treatment. Our results suggest ...
Systemically administered melatonin has been reported to produce antinociception and to inhibit s... more Systemically administered melatonin has been reported to produce antinociception and to inhibit spinal nociceptive transmission in rats. The present study was designed to investigate in anesthetized rats (i) whether intrathecally administered melatonin can depress synaptic potentiation (wind-up) in the spinal cord, and (ii) whether this effect is prevented by intrathecal (i.t.) administration of the MT2 receptor antagonist luzindole. Results showed that melatonin i.t. (10, 30 and 90 microg) induced dose-dependent inhibition of wind-up activity (ED50=52.06 microg i.t.), an effect that was prevented by 100 microg i.t. of luzindole. Since wind-up is dependent on NMDA receptor activation, the results suggest that melatonin can interfere with the NMDA-mediated glutamatergic component of pain transmission in rat spinal cord by acting on MT2 receptors.
Melatonin has been shown to exert potent antinociception but the sites and mechanisms of action u... more Melatonin has been shown to exert potent antinociception but the sites and mechanisms of action underlying this effect have not yet been clarified. The effect of melatonin on spinal cord nociceptive transmission was studied in rats by assessing wid-up activity in a C-fiber reflex responses paradigm evoked by repetitive (0.6 Hz) electric stimulation. Intraperitoneal administration of 1.25, 2.5, 5.0 and 10.0 mg/kg melatonin induced a dose-dependent inhibition of spinal wind-up activity, the higher dose of the drug used being able to depress completely the C reflex gain. Results indicate that melatonin markedly depresses spinal wind-up in rats, probably through hyperpolarization of dorsal horn neurons consecutive to melatonin binding to membrane receptors, and/or via intracellular interference with a NMDA receptor-dependent nitric oxide generating pathway.
Summary DNA methylation is one of the epigenetic and hereditary mechanisms regulating genetic exp... more Summary DNA methylation is one of the epigenetic and hereditary mechanisms regulating genetic expression in mammalian cells. In this review, we propose how certain natural agents, through their dietary consumption, could induce changes in physiological aspects in mammalian mothers, leading to alterations in DNA methylation patterns of the developing fetus and to the emergence of new phenotypes and evolutionary change. Nevertheless, we hypothesize that this process would require (i) certain key periods in the ontogeny of the organism where the environmental stimuli could produce effects, (ii) particular environmental agents as such stimuli, and (iii) that a genomic persistent change be consequently produced in a population. Depending on the persistence of the environmental stimuli and on whether the affected genes are imprinted genes, induced changes in DNA methylation patterns could become persistent. Moreover, some fragments could be more frequently methylated than others over seve...
A detailed study of gametes development and characterization of plasma sex steroid hormones durin... more A detailed study of gametes development and characterization of plasma sex steroid hormones during the maturation cycle was performed for the first time in the southern hake (Merluccius australis). Fish were caught in the inland waters of the Reloncaví Sound, Interior Sea of Chiloé, Chile. Samples of gonads and blood were collected for histology and sex steroid hormone (17 β-estradiol, 11-ketotestosterone and 17,20 βdihydroxy-4-pregnen-3-one) analysis, respectively. Sex steroid hormone quantification was performed using enzyme-immunoassay (ELISA). Results showed that M. australis males and females have asynchronous development of testicles and ovaries, in all stages of maturation. Most spawning fish were found during the spring months. Regarding the sex steroid hormones, serological fluctuations of 17 β-estradiol and 11- ketotestosterone were found during gonadal maturation of M. australis. These hormones are the main hormones responsible for vitelogenesis and spermatogenesis proces...
The trophic action of LH on Leydig cells involves the triggering of a number of cellular events i... more The trophic action of LH on Leydig cells involves the triggering of a number of cellular events including changes in protein synthesis. This latter change has led a number of workers to postulate an effect of LH on RNA synthesis. A direct action of LH on RNA synthesis, however, has been difficult to assess. The aim of the present work was to analyse the effect of LH on RNA synthesis in vitro during sexual development. Studies were performed using purified Leydig cells from rats of 20, 30, 40, 50, 60 and 90 days of age. The results obtained show that basal uridine incorporation into RNA increases in an age-dependent manner in rats from 20 to 60 days of age and then remains unchanged until 90 days of age. A stimulatory effect of LH on RNA synthesis was clearly demonstrated only in the youngest rats (20 and 30 days old). In order to differentiate the effect of LH on different RNA populations, the RNA synthesized by immature and mature rats was analysed using a poly(U)-Sepharose column....
Human diet contains a series of bioactive vegetal compounds that can improve human health. Among ... more Human diet contains a series of bioactive vegetal compounds that can improve human health. Among these, there has been a special interest for phytoestrogens. This article reviews the evidence about the potential benefits of phytoestrogens for human health. Forty eight manuscripts were selected for their study design and relevance to human health. The cell growth inhibitory effects of phytoestrogens and their implication in breast cancer are reviewed. Also the effects of these compounds on serum lipid levels and the effectiveness of a phytoestrogen derivate, ipriflavone, on the prevention of osteoporosis are analyzed. Although these compounds have a great potential for improving health, there is still not enough evidence to recommend the routine use of phytoestrogens.
Advances in experimental medicine and biology, 2008
A stable cyclized 9-mer peptide (cP) containing the active site of alpha-alpha fetoprotein (alpha... more A stable cyclized 9-mer peptide (cP) containing the active site of alpha-alpha fetoprotein (alphaFP) has been shown to be effective for prevention of estrogen-stimulated tumor cell proliferation in culture or of xenographt growth in immunodeficient mice. cP does not block 17beta-estradiol (E2) binding to its receptors, but rather appears to interfere with intracellular processing of the signal that supports growth. To obtain insight on that mechanism we studied the effect of cP on the proliferation of MCF-7 cells in culture. Proliferation in the presence of 2 microM E2 is decreased up to 40% upon addition of 2 microg ml(-1) cP to the medium; the presence of cP did not increase cell death, cP reduced also the proliferation of estrogen-dependent ZR75-1 cells but had no effect on autonomous MDA-MB-231 cells, cP did not modify the number of binding sites for labeled E2 or affected cell death. We detected increased nuclear p21Cip1 immunoreactivity after cP treatment. Our results suggest ...
Systemically administered melatonin has been reported to produce antinociception and to inhibit s... more Systemically administered melatonin has been reported to produce antinociception and to inhibit spinal nociceptive transmission in rats. The present study was designed to investigate in anesthetized rats (i) whether intrathecally administered melatonin can depress synaptic potentiation (wind-up) in the spinal cord, and (ii) whether this effect is prevented by intrathecal (i.t.) administration of the MT2 receptor antagonist luzindole. Results showed that melatonin i.t. (10, 30 and 90 microg) induced dose-dependent inhibition of wind-up activity (ED50=52.06 microg i.t.), an effect that was prevented by 100 microg i.t. of luzindole. Since wind-up is dependent on NMDA receptor activation, the results suggest that melatonin can interfere with the NMDA-mediated glutamatergic component of pain transmission in rat spinal cord by acting on MT2 receptors.
Melatonin has been shown to exert potent antinociception but the sites and mechanisms of action u... more Melatonin has been shown to exert potent antinociception but the sites and mechanisms of action underlying this effect have not yet been clarified. The effect of melatonin on spinal cord nociceptive transmission was studied in rats by assessing wid-up activity in a C-fiber reflex responses paradigm evoked by repetitive (0.6 Hz) electric stimulation. Intraperitoneal administration of 1.25, 2.5, 5.0 and 10.0 mg/kg melatonin induced a dose-dependent inhibition of spinal wind-up activity, the higher dose of the drug used being able to depress completely the C reflex gain. Results indicate that melatonin markedly depresses spinal wind-up in rats, probably through hyperpolarization of dorsal horn neurons consecutive to melatonin binding to membrane receptors, and/or via intracellular interference with a NMDA receptor-dependent nitric oxide generating pathway.
Summary DNA methylation is one of the epigenetic and hereditary mechanisms regulating genetic exp... more Summary DNA methylation is one of the epigenetic and hereditary mechanisms regulating genetic expression in mammalian cells. In this review, we propose how certain natural agents, through their dietary consumption, could induce changes in physiological aspects in mammalian mothers, leading to alterations in DNA methylation patterns of the developing fetus and to the emergence of new phenotypes and evolutionary change. Nevertheless, we hypothesize that this process would require (i) certain key periods in the ontogeny of the organism where the environmental stimuli could produce effects, (ii) particular environmental agents as such stimuli, and (iii) that a genomic persistent change be consequently produced in a population. Depending on the persistence of the environmental stimuli and on whether the affected genes are imprinted genes, induced changes in DNA methylation patterns could become persistent. Moreover, some fragments could be more frequently methylated than others over seve...
A detailed study of gametes development and characterization of plasma sex steroid hormones durin... more A detailed study of gametes development and characterization of plasma sex steroid hormones during the maturation cycle was performed for the first time in the southern hake (Merluccius australis). Fish were caught in the inland waters of the Reloncaví Sound, Interior Sea of Chiloé, Chile. Samples of gonads and blood were collected for histology and sex steroid hormone (17 β-estradiol, 11-ketotestosterone and 17,20 βdihydroxy-4-pregnen-3-one) analysis, respectively. Sex steroid hormone quantification was performed using enzyme-immunoassay (ELISA). Results showed that M. australis males and females have asynchronous development of testicles and ovaries, in all stages of maturation. Most spawning fish were found during the spring months. Regarding the sex steroid hormones, serological fluctuations of 17 β-estradiol and 11- ketotestosterone were found during gonadal maturation of M. australis. These hormones are the main hormones responsible for vitelogenesis and spermatogenesis proces...
The trophic action of LH on Leydig cells involves the triggering of a number of cellular events i... more The trophic action of LH on Leydig cells involves the triggering of a number of cellular events including changes in protein synthesis. This latter change has led a number of workers to postulate an effect of LH on RNA synthesis. A direct action of LH on RNA synthesis, however, has been difficult to assess. The aim of the present work was to analyse the effect of LH on RNA synthesis in vitro during sexual development. Studies were performed using purified Leydig cells from rats of 20, 30, 40, 50, 60 and 90 days of age. The results obtained show that basal uridine incorporation into RNA increases in an age-dependent manner in rats from 20 to 60 days of age and then remains unchanged until 90 days of age. A stimulatory effect of LH on RNA synthesis was clearly demonstrated only in the youngest rats (20 and 30 days old). In order to differentiate the effect of LH on different RNA populations, the RNA synthesized by immature and mature rats was analysed using a poly(U)-Sepharose column....
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