HYPERINSULINEMIA IN RATS WITH OBESITY-INDUCING AMYGDALOID-LESIONS

Electrolytic lesions of the posterodorsal aspects of the medial divisi on of the extended amygdala in female rats result in hyperphagia and e xcessive weight gain. In the present study, the effects of such lesion s on plasma insulin, glucose, corticosterone, and adrenocorticotropic hormone were assessed during a period of food restriction and again af ter a 15-day period of food ad libitum. Compared with control animals, the rats with amygdaloid lesions were hyperinsulinemic under both con ditions and gained substantially more weight when fed ad libitum. No d ifference between groups was observed for the other hormones. It is co ncluded that damage to the posterodorsal aspects of the medial amygdal a results in a primary metabolic dysfunction that accounts, at least i n part, for the overeating and excessive weight gain.