FURTHER OBSERVATIONS ON THE RELATIVE ABSORPTION RATES OF PELLETS OF VARIOUS CRYSTALLINE COMPOUNDS IMPLANTED SUBCUTANEOUSLY IN RATS

Abstract

A uniform technique was employed for the prep., subcutaneous implantation in 87 sexually mature [male] and [female] rats, and removal of pellets of various crystalline compounds. The periods required for 90% absorption of the pellets were as follows: desoxycorticosterone acetate, 64 days; estriol, 93 days; androsterone, 120 days; estradiol, 180 days; estradiol dipropionate, 220 days; estradiol benzoate, 415 days. Cholesterol pellets were not absorbed. A loss of body wt. sometimes occurred in the presence of all compounds except desoxycorticosterone acetate and cholesterol. Pellets similarly made from large crystals and from small crystals of methyl testosterone, of desoxycorticosterone acetate, and of testosterone monopropionate were implanted in 59 sexually mature [male] and [female] rats. Pellets made from large crystals of a given compound had been absorbed at the same rate as pellets made from small crystals of the same compound.