CIRCADIAN ANORECTIC EFFECTS OF PERIPHERALLY ADMINISTERED AMYLIN IN RATS

The pancreatic peptide amylin (1 mu g/kg) injected intraperitoneally r educed cumulative food intake for up to 4 h in food-deprived (24 h) an d nondeprived rats at various times of the day, i.e., at dark onset, i n the middle of the dark phase, and at light onset. At none of these t imes did subdiaphragmatic vagotomy abolish the anorectic effect of amy lin. Rather, vagotomy enhanced, by unknown mechanisms, amylin's anorec tic effect in food-deprived rats at light onset and in the middle of t he dark phase. In contrast to previous studies with older rats, amylin 's anorectic effect was also observed when injected into nondeprived r ats. The findings of the present study extend previous reports in that amylin's anorectic effect, not being abolished by abdominal vagotomy after intraperitoneal injection, can be elicited at different times of the day.