Abstract
Rockland and Buffalo-Marsh mice were castrated at approx. 5 wks. of age. One mo. later, pure testosterone propionate pellets were implanted subcut. and the animals killed at intervals over a period of 96 days and the various organs weighed. The pellets were absorbed at a gradual rate such that the 11 [plus or minus] mg. size would have been absorbed completely in 80-90 days and the 22 [plus or minus] mg. size in 120-130 days. As a result of the androgen therapy, the seminal vesicles and prostates and the kidneys attained sizes greater than twice the normal, the castration-hypertrophied thymi were involuted to 1/3 of normal, and the castration-hypertrophied adrenals to normal, and the heart and liver were slightly enlarged. A decrease in plasma K as a result of castration and a return to normal by the androgen therapy was observed. The Buffalo-Marsh mice proved very satisfactory for quantitative work.