Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0155339 (Brown)
 12,436 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The age-related decrease in serum T levels is associated with impairments in food intake and weight regulation and alterations in brain peptides that regulate energy balance. To test the hypothesis that reduced T levels contribute to altered hypothalamic cocaine-amphetamine-regulated transcript (CART) and NPY gene expression, the mRNA content of these neuropeptides was measured by in situ hybridization in sham-operated (intact), castrated, and T-replaced castrated young and old male Brown Norway rats. T levels in T-replaced young and old rats were similar to those in intact young animals. Compared with castrated rats, arcuate nucleus CART mRNA was lower and NPY mRNA was higher in both young and old T-replaced castrated animals, suggesting reciprocal regulation of these peptides by T; these T-induced changes were localized primarily in the rostral arcuate and were markedly attenuated in old animals. Compared with intact animals, paraventricular nucleus CART mRNA was lower in castrated animals and similar in T-replaced young and old rats. We conclude that hypothalamic CART and NPY neurons remain responsive to T regulation in old rats, albeit less so than in young animals, suggesting that the age-related reduction of T contributes in part to altered brain neuropeptide gene expression favoring anorexia and wasting with aging.
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PMID:Testosterone (T)-induced changes in arcuate nucleus cocaine-amphetamine-regulated transcript and NPY mRNA are attenuated in old compared to young male brown Norway rats: contribution of T to age-related changes in cocaine-amphetamine-regulated transcript and NPY gene expression. 1186 18

Compared to younger animals, aged male Brown Norway (BN) rats demonstrate increased body fat and serum insulin, and lower prepro-neuropeptide Y (ppNPY) mRNA content in the arcuate nucleus (ARC), and blunted food intake (FI) and body weight (BW) gain in response to a 72 h fast. Since centrally administered insulin decreases FI and weight of young rats and inhibits fasting-induced increases of NPY gene expression, we hypothesized that hyperinsulinemia in old rats contributes to an age-related central dysregulation of energy balance. Young, middle-aged and old BN rats were fed chow with troglitazone (Trog; 200 mg/kg BW/d) or without drug for 75 d (Experiment 1) or 66 d (Experiment 2). Rats were then fasted for 72 h, refed for 2 weeks and sacrificed after an overnight fast (Experiment 1) or fasted for 72 h and sacrificed (Experiment 2). Serum insulin and leptin were measured from trunk blood and brains were analyzed for ppNPY mRNA by in situ hybridization. In Experiment 1, troglitazone treatment resulted in increased post-fast weight gain, rate of gain and FI in old rats. Troglitazone decreased serum insulin by 50% in old rats, while leptin levels decreased 20-30% in all age groups in Experiment 1. No differences in serum insulin or leptin were detectable with troglitazone treatment in Experiment 2, due to the extreme suppression caused by the 72 h fast. Troglitazone treatment did not increase ARC NPY gene expression either after a 72 h fast and re-feeding for 2 weeks (Experiment 1) or immediately after a 72 h fast (Experiment 2). These findings suggest that increased insulin levels may contribute to age-related impairments of FI and BW regulation. However, improvements in these defects in energy regulation induced by troglitazone do not appear to result from changes in NPY gene expression, and may be due to alterations in other hypothalamic neuropeptides that regulate energy balance.
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PMID:Troglitazone treatment of aging Brown Norway rats improves food intake and weight gain after fasting without increasing hypothalamic NPY gene expression. 1190 85

Aging mammals lose the ability to maintain energy balance, exhibiting decreased appetite (anorexia) and impaired ability to maintain body weight. To determine the contribution of hypothalamic neuropeptides, two experiments were performed in male Brown Norway rats. To assess the hypothalamic neuropeptide response to food deprivation, young (Y; 4 mo old), middle-aged (M; 13 mo), and old (O; 25 mo) rats were either ad libitum fed or fasted for 72 h (n = 10/group) and killed. Hypothalamic levels of agouti-related peptide (AgRP), proopiomelanocortin (POMC), and cocaine-amphetamine-regulated transcript (CART) mRNA were assessed by in situ hybridization. With aging, arcuate AgRP gene expression decreased and CART mRNA increased, but POMC mRNA did not change. Fasting-induced changes in gene expression of all neuropeptides studied were attenuated with aging. To test the food intake response to appetite-stimulating neuropeptides, Y, M, O, and very old (VO; 33 mo) rats (n = 4-8/group) received one intracerebroventricular injection of each of three treatments: 0.1 nmol AgRP, 2.34 nmol NPY, and saline control. AgRP increased food intake of all groups by 10-20%, compared with saline, and this effect persisted up to 7 days after injection. VO animals were more sensitive to the effects of AgRP than younger animals. In contrast, NPY increased food intake more in Y than in older animals and its effects did not last >24 h. We conclude that the mechanisms by which arcuate nucleus neurons influence appetite are differentially affected by age and speculate that the melanocortin system may be a useful target for treatment of the anorexia of aging.
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PMID:Blunted hypothalamic neuropeptide gene expression in response to fasting, but preservation of feeding responses to AgRP in aging male Brown Norway rats. 1500 33