Albrecht E D
Biol Reprod. 1985 Sep;33(2):432-5. doi: 10.1095/biolreprod33.2.432.
The concentrations of serum progesterone (P4) were determined in 3- and 11-mo-old female rats throughout pregnancy to determine if the subnormal ovarian formation of P4 from pregnenolone (P5), previously shown in vitro in the older rats, is accompanied by lower concentrations of P4 in the peripheral serum. Beginning on Day 11 of gestation and continuing throughout the remainder of pregnancy, 11-mo-old females exhibited a decline in the number of live fetuses and an increase in the number of dead fetuses. Between Days 1 and 8 of gestation, serum P4 concentrations were similar in young and aging females. Between Days 9 and 21 of gestation, serum P4 concentrations in aging rats that maintained pregnancy, or that exhibited fetal loss, were consistently greater than in the young animals. The normal or above-normal concentrations of serum P4, despite the subnormal ovarian formation of P4 demonstrable in vitro in 11-mo-old females during the first half of pregnancy, may reflect an alteration in the peripheral catabolism of P4 or no change in ovarian secretion of P4 in vivo. Despite the changes in ovarian steroidogenesis observed in vitro, pregnancy failure in aging female rats is not related simply to subnormal content of P4 in the peripheral circulation.
在整个孕期测定了3月龄和11月龄雌性大鼠的血清孕酮（P4）浓度，以确定先前在老年大鼠体外实验中显示的孕烯醇酮（P5）向P4的卵巢生成低于正常水平时，外周血清中P4浓度是否也较低。从妊娠第11天开始并持续至整个孕期剩余时间，11月龄雌性大鼠的活胎数量减少，死胎数量增加。在妊娠第1天至第8天期间，年轻和老龄雌性大鼠的血清P4浓度相似。在妊娠第9天至第21天期间，维持妊娠或出现胎儿丢失的老龄大鼠的血清P4浓度始终高于年轻动物。尽管在妊娠前半期11月龄雌性大鼠体外实验显示卵巢生成P4低于正常水平，但血清P4浓度正常或高于正常，这可能反映了P4外周分解代谢的改变或体内P4卵巢分泌未发生变化。尽管在体外观察到卵巢类固醇生成有变化，但老龄雌性大鼠的妊娠失败并非仅仅与外周循环中P4含量低于正常水平有关。
