Hyperphagia in the Insulin-Treated Rat ∗

Abstract

Summary

Protamine zinc insulin (PZI) was administered daily to male rats by subcutaneous injection (2 units/100 gm of body weight) and comparisons were made with saline-injected control animals. As a consequence of PZI administration, the following observations were made: hyperphagia, increased body weight gain, increased lipogenesis from acetate-1-¹⁴C and glucose-U-¹⁴C, and no alteration in oxidation of glucose-U-¹⁴C to ¹⁴CO_2, in lipolysis in vitro, nor in the fat concentration of adipose tissue. These results are compared with those reported previously with hypothalamic-hyperphagic rats and it is concluded that the metabolic mechanisms of increased fat deposition differ between the two forms of hyperphagia.