Rodolfo Cardoso

Timing of puberty and subsequent fertility in female mammals are dependent on the integration of metabolic signals by the hypothalamus. Proopiomelanocortin (POMC) neurones in the arcuate nucleus (ARC) comprise a critical metabolic-sensing pathway controlling the reproductive neuroendocrine axis. Melanocyte-stimulating hormone alpha (αMSH), a product of the POMC gene, has excitatory effects on gonadotropin-releasing hormone (GnRH) neurones and fibres containing αMSH project to GnRH and kisspeptin neurones. Because kisspeptin is a potent stimulator of GnRH release, αMSH may also stimulate GnRH secretion indirectly via kisspeptin neurones. Here, we report studies in young female cattle (heifers) to determine whether increased nutrient intake during the juvenile period (4-8 months of age), a strategy previously shown to advance puberty, alters POMC and KISS1 mRNA expression, and αMSH close contacts on GnRH and kisspeptin neurones. In experiment 1, POMC mRNA expression, detected by in situ hybridisation, was greater (P < 0.05) in the ARC in heifers that gained 1 kg/day of body weight (high-gain, HG; n = 6) compared to heifers that gained 0.5 kg/day (low-gain, LG; n = 5). The number of KISS1-expressing cells in the middle ARC was reduced (P < 0.05) in HG compared to LG heifers. In experiment 2, double-immunofluorescence showed limited αMSH-positive close contacts on GnRH neurones, and the magnitude of these inputs was not influenced by nutritional status. Conversely, a large number of kisspeptin-immunoreactive cells in the ARC were observed in close proximity to αMSH-containing varicosities. Furthermore, HG heifers (n = 5) exhibited a greater (P < 0.05) percentage of kisspeptin neurones in direct apposition to αMSH fibres and an increased (P < 0.05) number of αMSH close contacts per kisspeptin cell when compared to LG heifers (n = 6). These results indicate that the POMC-kisspeptin pathway may be important in mediating the nutritional acceleration of puberty in heifers. This article is protected by copyright. All rights reserved.

The susceptibility of the reproductive system to early exposure to steroid hormones has become a major concern in our modern societies. Human fetuses are at risk of abnormal programming via exposure to endocrine disrupting chemicals, inadvertent use of contraceptive pills during pregnancy, as well as from excess exposure to steroids through disease states. Animal models provide an unparalleled resource to understand the developmental origin of diseases. In female sheep, prenatal exposure to testosterone (T) excess results in an array of adult reproductive disorders that recapitulate those seen in women with polycystic ovary syndrome (PCOS), including disrupted neuroendocrine feedback mechanisms, increased pituitary sensitivity to gonadotropin-releasing hormone (GnRH), luteinizing hormone (LH) excess, functional hyperandrogenism, and multifollicular ovarian morphology culminating in early reproductive failure. Prenatal T-treatment also leads to fetal growth retardation, insulin resis...

Feeding a high-concentrate diet to heifers during the juvenile period, resulting in increased body weight (BW) gain and adiposity, leads to early-onset puberty. In this study, we tested the hypothesis that the increase in GnRH/LH release during nutritional acceleration of puberty is accompanied by reciprocal changes in circulating leptin and central release of neuropeptide Y (NPY). The heifers were weaned at 3.5 months of age and fed to gain either 0.5 (Low-gain; LG) or 1.0 kg/day (High-gain; HG) for 30 weeks. A subgroup of heifers was fitted surgically with third ventricle guide cannulas and was subjected to intensive cerebrospinal fluid (CSF) and blood sampling at 8 and 9 months of age. Mean BW was greater in HG than in LG heifers at week 6 of the experiment and remained greater thereafter. Starting at 9 months of age, the percentage of pubertal HG heifers was greater than that of LG heifers, although a replicate effect was observed. During the 6-h period in which CSF and blood we...

Increased body weight (BW) gain during the juvenile period leads to early maturation of the reproductive neuroendocrine system. We investigated whether a nutritional regimen that advances the onset of puberty leads to alterations in the hypothalamic neuropeptide Y (NPY) circuitry that are permissive for enhanced gonadotropin-releasing hormone (GnRH) secretion. It was hypothesized that NPY mRNA and NPY projections to GnRH and kisspeptin neurons are reduced in heifers that gain BW at an accelerated rate, compared with a lower one, during the juvenile period. Heifers were weaned at approximately 4 mo of age and fed diets to promote relatively low (0.5 kg/day; low gain [LG]) or high (1.0 kg/day; high gain [HG]) rates of BW gain until 8.5 mo of age. Heifers that gained BW at a higher rate exhibited greater circulating concentrations of leptin and reduced overall NPY expression in the arcuate nucleus. The proportion of GnRH neurons in close apposition to NPY fibers and the magnitude of NP...

According to KUJALA and LILLRANK (2004), an organization can select their management practices among a vast existent group of having "presented" through multiple channels (manuals, publications, consultancies, etc.) and that they present different return possibilities. On the other hand, the choice of those management practices is a complex activity of modelling that goes by the need of adjustments looking for

... Rodolfo Cardoso – rodolfo.cardoso@gpi.ufrj.br Thaís Spiegel – thais.spiegel@gpi.ufrj.br Heitor Mansur Caulliraux – heitor.caulliraux@gpi.ufrj.br ... 3 à longo prazo por meio da satisfação de cliente, e benefícios para a organização e para sociedade.” ...

Purpose – The purpose of this paper is to contribute to defining the tasks necessary to process management, considering both conceptual and practical views. Design/methodology/approach – Bibliographic review for tasks mentioned as typically necessary to process management, plus a field survey involving professionals working in process management. Findings – The bibliographic review yielded a set of tasks that were grouped