Charles W. Hooker

Effects of Progesterone Upon the Uterus of the Mouse.

Summary With or without concomitant treatment with estrogen, the daily injection of 0.25 or 0.5 mg of progesterone into mice ovariectomized 3 weeks previously evoked mitosis in all the tunics of the uterus. The nuclei of the cells of the uterine tunica propria became larger and transformed from the fusiform, pyknotic type into vesicular nuclei. The latter condition was also seen in pregnant and lactating mice. Neither estrogen alone nor androgen provoked this morphology.

Inactivity of bound plasma progesterone.

Summary Pellets of crystalline progesterone implanted into the spleens of ovariectomized mice had no effect upon the endometrium despite the presence of relatively high levels of bound progesterone in the plasma; the highest level of free progesterone in these animals was 0.7 μg per ml. Subcutaneous pellets of progesterone produced characteristic progestational changes in the endometrium when the level of free plasma progesterone exceeded 1.0 μg per ml. Binding appears to be a mechanism of hepatic inactivation of progesterone in the mouse.

Plasma Progesterone Levels and the Menstrual Cycle of the Monkey.

Summary Bioassay of the free and bound plasma progesterone at various intervals through a menstrual cycle in each of 2 monkeys indicate the level of free progesterone to be low during and following menstruation, high near the middle of the cycle, lower following this peak, and high in the latter half of the cycle. A low level was present at or preceding menstruation. The levels of the bound fraction were low at all times.

Failure of the liver of the monkey to inactivate estrogens in vivo.

Summary 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.