Aspects of neuroregulation of body composition and insulin secretion

Perturbances in the autonomic nervous control of different target tissues (e.g. endocrine pancreas, brown adipose tissue) are present in the genetically obese (fa/fa) rat. These disorders are probably secondary to central dysregulation(s). In view of the reported effects of CRF in stimulating sympathetic nerve-mediated mechanisms while inhibiting vagus nerve-mediated ones, ovine CRF (oCRF) was administered for 7 days into the cerebral ventricles of fa/fa rats. oCRF treatment stopped the excessive weight gain of the obese animals. The oCRF effect was unrelated to changes in food intake, as the two groups were pair-fed. oCRF-treated obese rats were characterized by a decrease in basal hyperinsulinemia, increases in brown adipose tissue weight and activity, and decreases in hepatic glycogen content and epididymal fat pad weight. It is suggested that intracerebroventricular oCRF administration to obese fa/fa rats prevents the increase in body weight observed in vehicle-infused obese rats by modulating the impaired autonomic nervous control of different target tissues. This does not occur in lean rats.