Hypothalamic glucose sensing is involved in the control of feeding behavior and peripheral glucose homeostasis, and glial cells are suggested to play an important role in this process. Diazepam-binding inhibitor (DBI) and its processing product the octadecaneuropeptide (ODN), collectively named endozepines, are secreted by astroglia, and ODN is a potent anorexigenic factor. Therefore, we investigated the involvement of endozepines in brain glucose sensing. First, we showed that intracerebroventricular administration of glucose in rats increases DBI expression in hypothalamic glial-like tanycytes. We then demonstrated that glucose stimulates endozepine secretion from hypothalamic explants. Feeding experiments indicate that the anorexigenic effect of central administration of glucose was blunted by coinjection of an ODN antagonist. Conversely, the hyperphagic response elicited by central glucoprivation was suppressed by an ODN agonist. The anorexigenic effects of centrally injected glucose or ODN agonist were suppressed by blockade of the melanocortin-3/4 receptors, suggesting that glucose sensing involves endozepinergic control of the melanocortin pathway. Finally, we found that brain endozepines modulate blood glucose levels, suggesting their involvement in a feedback loop controlling whole-body glucose homeostasis. Collectively, these data indicate that endozepines are a critical relay in brain glucose sensing and potentially new targets in treatment of metabolic disorders.
As nursing home residents age, substitute homes have to adapt if they are to continue offering opportunities for self-actualization and a continuing sense of identity. Opinions of elderly residents and their families are very helpful for occupational therapists particularly when designing programs in long-term care facilities.
The sex steroids, estrogens, progesterone, and androgens, all play a role in mammary development and function. To precisely identify the sites of action of these steroids, we studied the localization of the estrogen receptor alpha (ERalpha) and ERbeta, the progesterone receptor A (PRA) and PRB, and androgen receptors (AR) in the normal human mammary gland. Immunocytochemical localization of ERalpha, ERbeta, PRA, PRB, and AR was performed with reduction mammoplasty specimens from premenopausal women. ERalpha, PRA, PRB, and AR were localized mostly to the inner layer of epithelial cells lining acini and intralobular ducts, as well as to myoepithelial cells scattered in the external layer of interlobular ducts. AR was also found in some stromal cells. ERbeta staining was more widespread, resulting in epithelial and myoepithelial cells being labeled in acini and ducts as well as stromal cells. These results suggest that all sex steroids can directly act on epithelial cells to modulate development and function of the human mammary gland. Estrogens and androgens can also indirectly influence epithelial cell activity by an action on stromal cells.
Introduction One mechanism by which low sexual steroid activity observed after menopause could cause sexual dysfunction is by deficient vaginal innervation. Recently, it has been shown that intravaginal administration of dehydroepiandrosterone (DHEA) could produce beneficial effects on sexual dysfunction in postmenopausal women. Aim The goal of this study was to determine if DHEA could modify innervation in the rat vagina. Main Outcome Measures The area occupied by the nerve fibers immunoreactive for protein gene product 9.5 (PGP 9.5), a panneuronal marker or tyrosine hydroxylase (TH), a sympathetic nerve fiber marker, in the lamina propria and muscular layers, respectively, as well as the total area of each of these 2 layers were measured by stereological analysis. Methods The innervation of the rat vagina was examined 9 months after ovariectomy (OVX) compared to intact animals and treatment of OVX animals with DHEA (80 mg/kg). Four sections from each vagina (5 animals/groups) were immunostained. Results In OVX animals, the lamina propria area was decreased to 44%, an effect which was reversed by DHEA to 69% of the intact value. OVX also caused a 59% decrease in the area of PGP 9.5 fibers, an effect which was prevented by DHEA, thus showing a 68% stimulatory effect of DHEA on the density of PGP 9.5 fibers in the lamina propria compared to OVX animals. Following OVX, the muscular layer area was decreased by 61%. DHEA treatment induced 118% and 71% increases in TH fiber area compared to OVX and intact animals, respectively. The density of TH fibers was 182% increased over intact controls by DHEA treatment of OVX animals. Conclusions The relatively potent stimulatory effect of DHEA on intravaginal nerve fiber density provides a possible explanation for the beneficial effects of intravaginal DHEA on sexual dysfunction observed in postmenopausal women.
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