RESPONSE TO GROWTH HORMONE OF HYPOPHYSECTOMIZED RATS WHEN RESTRICTED TO FOOD INTAKE OF CONTROLS

Abstract

[female] immature hypophysectomized rats were injected with purified preps. of ant. pituitary growth hormone which were practically free of other "contaminating" pituitary "target organ" hormones. The food intake of these rats was restricted to that of untreated controls by means of feeding by stomach tube and Mitchell''s paired feeding method respectively. Despite this identical food intake. there resulted a remarkable increase in body wt. of the treated rats, as against practical growth stasis in the control group. This would indicate that the growth hormone caused increased deposition of tissue substance, not as a consequence of an increased food intake, but through better utilization of the food eaten. All internal organs examined were heavier in the groups of rats treated with growth hormone. The organs grew only approx. at the same rate as did the body as a whole, with the exception of the thymus, which grew considerably faster.