Ovarian and placental origins of plasma progesterone following fetectomy in monkeys (Macaca mulatta).
Fetectomy, either alone or combined with ovariectomy, was performed in 17 monkeys. Following fetectomy alone in 8 animals, progesterone values were maintained at normal pregnancy levels (1.0 ng/cc plasma or more), until expulsion of the placenta, which frequently occurred at a time well past normal term. Values declining toward but not reaching the nonpregnancy range were observed in some animals in the 2 to 6 weeks preceding expulsion; no similar decline occurs preceding normal labor. In all cases, after the placenta was expelled, progesterone values fell below 1 ng/cc plasma within 2 days. When ovariectomy was superimposed on 3 animals previously fetectomized, plasma progesterone values fell abruptly to nonpregnancy levels, and the placenta was expelled in an average of 6.3 days. The source of the progesterone in these fetectomized animals was, therefore, the ovaries, not the placenta damaged by a preceding fetectomy. However, the ovarian progesterone production after fetectomy was dependent on the continued presence of the placenta. In 6 animals following ovariectomy, and with an intact fetus and placenta, plasma progesterone levels were usually maintained at normal pregnancy levels. When fetectomy was superimposed in these animals with a preceding ovariectomy, plasma progesterone levels fell into the nonpregnancy range in an average of 4.8 days, and placental expulsion occurred after an average of 30.8 days. We believe this reflected a deteriorating ability of the fetectomized placenta to produce progesterone, which was capable only transiently of maintaining plasma values, but later of exerting sufficient local effect to maintain uterine quiescence for a longer time.
D000818:Animals; D002369:Castration; D005260:Female; D005333:Fetus / Q000502:physiology*; D008251:Macaca; D010053:Ovary / Q000378:metabolism*; D010920:Placenta / Q000378:metabolism*; D011247:Pregnancy; D011270:Pregnancy, Animal; D011374:Progesterone / Q000097:blood*; D013997:Time Factors
D011374:Progesterone