The thermogenic property of progesterone.
Previous observations support the belief that the midcycle thermal shift occurs immediately after ovulation. The biphasic character of the basal body temperature during an ovarian cycle should be related to the 2 phases of secretory activity in the ovary. The opposed thermic effects of the ovarian steroids was studied in female castrates. Observations were correlated with the temperature-altering effects of estrogen and progesterone when administered during each phase of the cycle in regularly menstruating women. 26 surgically castrated and 6 intact, regularly menstruating women, aged 22-54, were selected for study. The bilateral oophorectomy of each of the 26 castrates had been performed by a member of the Department of Gynecology of the Graduate Hospital, University of Pennsylvania. The 6 regularly menstruating women were hospital patients. The experimental facts comprised the daily waking temperature, taken rectally. Ethinyl estradiol was the estrogen and pregneninolone the progesterone employed in all of the castrated subjects. 4 types of experiments were performed in the 12 castrates who took and recorded their rectal temperature daily for 2-4 months: 1) estrogen alone as administered, 2) progestogen alone, 3) estrogen followed by progestogen, and 4) estrogen and progestogen simultaneously. Ethinyl estradiol lowered the waking temperature from .2 to .4 degrees Farenheit in 18 of 27 tests. 60 mg of pregneninolone daily raised by body temperature from .4 to .6 degrees Farenheit in 20 of 30 trials, but 80 mg daily caused a slightly higher thermogenic response in 19 of 22 experiments. Successively administered ethinyl estradiol and pregneninolone resulted in an estrogen-evoked depression followed by a progestogen stimulated elevation of temperatuure in 11 of 15 attempts. The simultaneous administration of .15 mg of ethinyl estradiol and 60 mg of pregneninolone daily resulted in a slight rise of the basal body temperature in 12 of 17 trials. The temperature-depressing effect of estrogen and the thermogenic property of progestogen were demonstrated in the 6 menstruating women.