Long-term oral administration of dehydroepiandrosterone has different effects on energy intake of young lean and obese male Zucker rats when comparedto controls of similar metabolic body size

Aim: The effects of dehydroepiandrosterone (DHEA) on appetite and weight in the Zucker rat have been examined by many investigators who have reported appetite suppression and metabolic effects. However, these studies compared the treated animals to controls of a similar age. Since animals of differe nt sizes consume different amounts of food, perhaps the treated animals sho uld be compared to controls of a similar size. We studied the effects of DH EA on energy intake and weight gain and analysed the effects by age and met abolic body size. Methods: Lean (n = 21) and obese (n = 16) male Zucker rats were fed plain c how or chow containing 6 g DHEA/kg chow (0.6% wt/wt) from age 4 wk to 20 wk . Daily energy intakes and body weights were determined at least once weekl y. Results: As expected, the lean and obese rats given DHEA exhibited less dai ly energy intake (kJ/d) and less weight gain than their respective controls of the same age. The lean rats given DHEA did not exhibit any difference i n daily energy intake when determined relative to body weight (b.w.) (kJ x d(-1) x g b.w.(-1)) compared to lean controls of the same metabolic body si ze, while the obese rats given DHEA exhibited less daily energy intake rela tive to b.w. (kJ x d(-1) x g b.w.(-1)) compared to obese control of the sam e metabolic body size. Conclusions: Though DHEA reduced total energy intake among the lean and obe se Zucker rats, only the obese rats exhibited less energy intake relative t o b.w. compared to controls of the same metabolic body size. Thus, DHEA may exert different effects on energy intake relative to b.w. in lean and obes e Zucker rats and perhaps the lean Zucker rat is a better model for evaluat ing the metabolic effects of DHEA since it does not exhibit any effect on e nergy intake relative to b.w. compared to rats of the same metabolic body s ize.