Intraventricular insulin reduces food intake and body weight of lean but not obese Zucker rats

H Ikeda, DB West, JJ Pustek, DP Figlewicz… - Appetite, 1986 - Elsevier
H Ikeda, DB West, JJ Pustek, DP Figlewicz, MRC Greenwood, D Porte Jr, SC Woods
Appetite, 1986Elsevier
Porcine insulin (2 mU/rat/day) and its saline vehicle were infused into the third cerebral
ventricle of female lean or obese Zucker rats using 14-day osmotic minipumps. Lean rats
receiving saline (N= 6) gained 14±3 g over the 14 days, whereas lean rats receiving insulin
(N= 7) lost 12±4 g over the same interval (p< 0· 01). The average total food intake of the
insulin-infused group was decreased by 14%(p< 0· 05) as compared with that of the saline-
infused group. The decreased caloric consumption was adequate to account for the body …
Porcine insulin (2 mU/rat/day) and its saline vehicle were infused into the third cerebral ventricle of female lean or obese Zucker rats using 14-day osmotic minipumps. Lean rats receiving saline (N = 6) gained 14±3 g over the 14 days, whereas lean rats receiving insulin (N = 7) lost 12±4 g over the same interval (p < 0·01). The average total food intake of the insulin-infused group was decreased by 14% (p < 0·05) as compared with that of the saline-infused group. The decreased caloric consumption was adequate to account for the body weight loss. Insulin infusion had no effect on food intake or body weight of the obese rats relative to their saline-infused controls (change in body weight: saline (N = 5), −14±23 g; insulin (N = 7), +3±14 g). These results suggest that genetically obese Zucker rats have reduced sensitivity to insulin in the central nervous system. We propose that this phenomenon may participate in the development and maintenance of hyperphagia and obesity in these animals.
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