Journal of neuroendocrinology
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J. Neuroendocrinol. · Aug 2010
Maternal overnutrition impacts offspring adiposity and brain appetite markers-modulation by postweaning diet.
Maternal obesity has long-term consequences for the development of hypothalamic neurones involved in energy homeostasis and the metabolic profile in offspring. In the present study, we compared the effects of maternal obesity induced by longstanding high-fat diet (HFD) with milder postnatal overfeeding during suckling induced by litter size reduction. Female Sprague-Dawley rats consumed chow (C) or HFD. ⋯ The data obtained suggest that even mild maternal overnutrition (CS) led to increased adiposity, glucose intolerance and altered brain appetite regulators in offspring. A greater impact of HFD-induced maternal obesity was evident. Marked additive effects were observed when animals consumed a HFD postweaning.
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J. Neuroendocrinol. · Jul 2009
ReviewGlial cells: indispensable partners of hypothalamic magnocellular neurones.
The hypothalamo-neurohypophysial system is comprised of magnocellular neurones that synthesise the neuropeptides oxytocin or vasopressin. As neurohormones, these peptides intervene in the regulation of vital functions such as parturition, lactation, osmotic and cardiovascular regulation. The release of these peptides in the general circulation depends on the electrical activity of their parent neurones, which in turn is regulated by the activity of their afferent inputs conveying distinct information. ⋯ An important gliotransmitter is the amino acid, d-serine, which, together with glutamate, activates NMDA receptors. Once activated, NMDA receptors govern the weight of individual inputs on magnocellular neurones and thus the impact of distinct types of information on neuronal activity. As reviewed here, numerous observations show that astrocytes must be considered as key elements in the functioning of the hypothalamo-neurohypophysial system.
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J. Neuroendocrinol. · Jul 2009
Ovarian-steroid modulation of locus coeruleus activity in female rats: involvement in luteinising hormone regulation.
The noradrenergic nucleus locus coeruleus (LC) has been reported to regulate luteinising hormone (LH) secretion in female rats. Both oestrogen and progestin receptors have been demonstrated in LC neurones, suggesting that these cells are possibly responsive to variations in circulating levels of ovarian steroids. We therefore evaluated changes in the activity of LC neurones during the oestrous cycle and after ovarian-steroid treatment in ovariectomised (OVX) rats, as determined by immunoreactivity to Fos-related antigens (FRA), which comprises all of the known members of the Fos family. ⋯ Bath application of progesterone significantly increased the spontaneous firing rate of OVX+E LC neurones. Our data suggest that ovarian steroids may physiologically modulate the activity of LC neurones in females, with possible implications for LH secretion. Moreover, oestradiol and progesterone appear to exert opposite and complementary effects (i.e. whereas oestradiol inhibits, progesterone, after oestradiol priming, stimulates LC activity).
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J. Neuroendocrinol. · Mar 2009
ReviewSex differences and the roles of sex steroids in apoptosis of sexually dimorphic nuclei of the preoptic area in postnatal rats.
The brain contains several sexually dimorphic nuclei that exhibit sex differences with respect to cell number. It is likely that the control of cell number by apoptotic cell death in the developing brain contributes to creating sex differences in cell number in sexually dimorphic nuclei, although the mechanisms responsible for this have not been determined completely. The milieu of sex steroids in the developing brain affects sexual differentiation in the brain. ⋯ The patterns of expression of Bcl-2 and Bax in the SDN-POA of postnatal female rats are changed to male-typical ones by treatment with oestrogen, which is normally synthesised from testicular androgen and affects the developing brain in males. In the AVPV of postnatal rats, apoptotic regulation also differs between the sexes, although Bcl-2 expression is increased and Bax expression and caspase-3 activity are decreased in females. The mechanisms of apoptosis possibly contributing to the creation of sex differences in cell number and the roles of sex steroids in apoptosis are discussed.
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J. Neuroendocrinol. · Jun 2008
ReviewAdaptive responses of the maternal hypothalamic-pituitary-adrenal axis during pregnancy and lactation.
Over the past 40 years, it has been recognised that the maternal hypothalamic-pituitary-adrenal (HPA) axis undergoes adaptations through pregnancy and lactation that might contribute to avoidance of adverse effects of stress on the mother and offspring. The extent of the global adaptations in the HPA axis has been revealed and the underlying mechanisms investigated within the last 20 years. Both basal, including the circadian rhythm, and stress-induced adrenocorticotrophic hormone and glucocorticoid secretory patterns are altered. ⋯ By contrast, in lactation suckling the young provides a neural stimulus that dampens the HPA axis circadian rhythm and reduces stress responses. Reduced noradrenergic input activity is involved in reduced stress responses in lactation, although central prolactin action also appears important. Such adaptations limit the adverse effects of excess glucocorticoid exposure on the foetus(es) and facilitate appropriate metabolic and immune responses.