Myotrophic Effects of Castration and Testosterone in Thyroidectomized Guinea Pigs

¹ From the Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma

Male guinea pigs of the inbred Hartley strain were castrated, thyroidectomized and castrated-thyroidectomized at 470–549 gm body weight. Thyroidectomy did not change the rate of growth of the body, carcass, internal organs or 48 individual muscles during the ensuing 51 days in either the normal or castrated animals. The administration of testosterone during the last 21 days in a group of castrated-thyroidectomized animals partially restored the weight of the castration-atrophied muscles while the seminal vesicles and prostates were increased to slightly above normal.