Effects of putative satiety peptides on feeding and drinking behavior in golden hamsters (Mesocricetus auratus)

A series of experiments was conducted to characterize the effects of putative satiety peptides on feeding in the Syrian hamster, a species known to have physiological feeding controls different from those of other animals. Peripheral injections of cholecystokinin octapeptide (CCK-8) reduced feeding in hamsters in a dose-related fashion. CCK-8 was equally effective in reducing food intake in female hamsters tested during the light and dark portions of the illumination cycle but was ineffective in males tested during the light portion. Systemic injections of proglumide, a putative CCK receptor antagonist, did not alter spontaneous food intake and did not reverse the suppression of feeding resulting from peripheral CCK-8 injections. Systemic injections of bombesin (BBS), thyrotropin releasing hormone (TRH), and calcitonin (CT) produced a dose-related suppression of food intake. BBS appeared to do so specifically. In contrast, TRH appeared to reduce feeding by temporarily debilitating the animals; CT, by evoking behavior (increased locomotor activity) incompatible with feeding. Intracerebroventricular (icv) injections of CCK-8, BBS, and CT produced dose-related inhibition of feeding, but only CCK-8 appeared to affect feeding behavior selectively. Reduced feeding after icv BBS was associated with excessive grooming, and icv CT, like systemic CT, increased locomotor behavior. These findings in the hamster are discussed in relation to peptidergic control of feeding in other species.