Effect of insulin and cortisone on weight gain, protein and fat content of rats.

Abstract

Male Wister rats weighing 240 ± 2 gm show an average protein and fat content of 41.6 gm, and 13.1 gm. During a period of normal growth, the body weight increases within 14 days to 311 gm, the protein content to 57 gm, and the fat content to 21.7 gm. Several groups of rats were subjected to experimental procedures for 14 days, after having reached a body weight of 240 gm. Administration of protamine zine insulin (12 u/day) greatly enhanced weight gain, and deposition of excess fat, without affecting accumulation of body protein. Cortisone (5 mg/day) produced variable results. Diminished gain of body weight and total body protein occurred in 60% of the animals while accumulation of body fat was normal. Some rats lost weight and body protein but comparatively less fat than animals losing fat due to food restriction. Weight loss was most frequently observed in rats with visible infections. Simultaneous administration of insulin (12 u/day) did not alter the cortisone effect on body protein but markedly increased accumulation of body fat. One hundred twenty units per day accelerated gain of body fat still more. Values were observed comparable to those found in rats receiving insulin only. The amount of total body fat closely paralleled the amount of adipose tissue the composition of which was not significantly altered by any of the hormonal manipulations.