OBESITY-INDUCED BY UNSPECIFIC EARLY POSTNATAL OVERFEEDING IN MALE ANDFEMALE RATS - HYPOPHAGIC EFFECT OF CCK-8S

The response to cholecystokinin (CCK) as a satiety peptide in obesity or anorexia has been tested mainly in extreme models of food intake co ntrol. In the present study, the effect of CCK-8S on food intake was i nvestigated in a nongenetic and less-stressful model of obesity due to unspecific early postnatal overfeeding in male and female rats. Reduc ing the normal litter size of ten to three newborn rats on day 3 of li fe led to an enhanced food intake resulting in an increased body weigh t until adulthood. Freely fed male and female, normal and obese rats w ere given 10 mu g/kg CCK-8S i.p. on day 41 and 40 mu g/kg CCK-8S on da y 91 of life and food intake was measured for 24 h. Compared with trea tment with saline (i.p.) 1 day before the test, the lower dose of 10 m u g/kg CCK-8S reduced food intake for 2 h in normal, but not in obese rats. Conversely, the higher dose of 40 mu g/kg CCK-8S reduced food in take in both normal and obese rats for 2 h, but this effect was more e vident in the obese rats. Moreover, the satiating effect of CCK-8S was more pronounced and longer lasting in male than in female rats. In su mmary, the data suggest that the response to CCK-8S differs in normal and obese rats and depends on sex.