Failure of the Liver of the Monkey to Inactivate Estrogens in vivo.

Intrasplenic implantation of pellets of estrone and estradiol in 4 ovari-ectomized monkeys was followed by reddening of the sex skin and alteration of the vaginal smear as promptly and with the same intensity as in a control animal given estradiol benzoate intramuscularly. Endometrial changes in the animals were alike, and removal of the intrasplenic pellet was followed by typical estrogen-deprivation menstruation. Liver function tests revealed no hepatic damage and administration of B vitamins did not reduce the activity of the intrasplenic estrogens.