Role of the perifornical hypothalamic monoamine neurotransmitter systems in anorectic effects of endotoxin.

The cachexia-anorexia syndrome, in which patients suffering from chronic illness lack the desire to eat and experience weight loss, creates a serious clinical problem when patients are attempting to overcome the disease process. Endotoxin (ET) has many actions in the brain and peripheral injections can affect regulation of monoamines in brain areas as diverse as the olfactory lobes and the locus coeruleus. Certainly, ET is involved in the febrile process and it plays a prominent role in the regulation of food intake and maintenance of body weight during chronic illnesses.

Dehydroepiandrosterone (DHEA) blocks the increase in food intake caused by neuropeptide Y (NPY) in the Zucker rat.

Recent studies have demonstrated that neuropeptide Y (NPY) reduced the neural production of dehydroepiandrosterone (DHEA) in frog hypothalamic explants. The objective of this study was to assess if DHEA can block the NPY induced increase in food intake in lean and obese Zucker rats. Rats were given one of the following four treatments: sterile water/dimethylsulfoxide (DMSO), NPY/DMSO, water/DHEA, and NPY/DHEA.

The influence of dehydroepiandrosterone and 8-OH-DPAT on the caloric intake and hypothalamic neurotransmitters of lean and obese Zucker rats.

The 5 HT(1A) receptor agonist 8-hydroxy-2-(di-n-propylamino)-tetraline (8-OH-DPAT) increases the food intake of satiated Zucker rats, both lean and obese. Associated with this increased intake are changes in the hypothalamic content of serotonin and its metabolite, 5-HIAA (5-hydroxyindole-3-acetic acid); serotonin is increased while the level of 5-HIAA is decreased. Analysis of individual 5-HIAA/5-hydroxytryptamine (5-HT) ratios, a measure of serotonin turnover indicate that 8-OH DPAT affected serotonin turnover equally and dramatically in both phenotypes.

Caloric intake and hypothalamic neurotransmitters in Zucker rats made acutely diabetic with streptozocin.

Zucker rats, lean and obese, treated with low dose intraperitoneal injections of streptozocin become hyperglycemic within 24h. Insulin levels fall, although the obese animal remains hyperinsulinemic. Associated with these changes in glucose and insulin there are transient decreases in caloric intake.

Evidence for hypothalamic K+(ATP) channels in the modulation of glucose homeostasis.

Several lines of evidence support the hypothesis that ATP-sensitive K+ channels (K+(ATP)) participate in the brain's regulation of peripheral glucose homeostasis. In testing this hypothesis we conducted a series of in vivo experiments using albino rats and bilateral intrahypothalamic injections of K+(ATP) channel blockers, glibenclamide and repaglinide. The results show that 0.

Levels of hypothalamic neurotransmitters in lean and obese Zucker rats.

Hypothalamic neurotransmitter levels were compared between groups of Zucker rats. Animals were grouped by gender, phenotype and preference for dietary fat. Before sacrifice all animals consumed a standard rat chow diet and were fasted overnight.