AJP - Endocrinology and Metabolism, Vol 242, Issue 1 19-E24, Copyright © 1982 by American Physiological Society
Effect of insulin on fat and protein deposition in diabetic lean and obese rats
C. P. Chan, L. J. Koong and J. S. Stern
Five-week-old male obese and lean Zucker rats were made comparably diabetic
by intracardiac injections of alloxan (65-72 mg/kg body wt). Lean rats were
then given daily injections of protamine zinc insulin at 3 doses: 0.25,
1.25, and 4.0 U.100 g body wt-1.day-1 for 3 wk. Obese rats received
identical amounts as corresponding lean controls independent of body
weights. The drop of blood glucose concentration after injections of
regular insulin and the percentage fall in radioactive plasma insulin after
injections of 125I-insulin were comparable in lean and obese rats. Weight
gain, fat gain, and protein gain over 21 days increased with increasing
amounts of insulin administered. However, at the same dose of insulin,
although weight gain was comparable, fat gain was higher and protein gain
was lower in obese rats when compared to lean controls. These results
suggest that the enhanced lipid deposition of the obese Zucker rat is not
totally dependent on insulin levels, but is exaggerated by
hyperinsulinemia.
