Bassett S G, Pepe G J
Department of Physiology, Eastern Virginia Medical School, Norfolk 23501.
Biol Reprod. 1987 Oct;37(3):606-11. doi: 10.1095/biolreprod37.3.606.
The placenta provides androgen precursors for ovarian estradiol (E2) production during the second half of gestation in the rat. However, no studies have measured E2 synthesis in vivo from circulating testosterone (T) or androstenedione (A) before or after Day 12 of gestation. In addition, it is not known whether the placenta near term continues to serve as the major source of androgens. Therefore, we measured the ovarian conversion of circulating T and A to E2 in vivo on Days 11, 16, and 21 of gestation (term = Day 23). Rats (N = 6-8/group) were anesthetized with pentobarbital and a constant infusion of [3H]T or [3H]A initiated via a jugular vein. After isotopic equilibrium was achieved at 60 min, blood samples were obtained from the contralateral jugular (J) vein and a uterine-ovarian (UO) vein, and the ovaries were removed. In a second group of rats on Day 16 of gestation, either the gravid uterus or both ovaries were removed after initiation of isotope infusion, and blood samples obtained 60 min later. Radiolabeled T, A, and E2 were isolated and purified by sequential paper chromatography. The concentration of [3H]E2 following infusion of either androgen was greater in the UO vein than in the J vein on Days 16 and 21 (p less than 0.02), but not on Day 11, of gestation. In animals infused with [3H]T, [3H]E2 (cpm/ml) in UO vein increased (p less than 0.001) from 84 +/- 33 (mean +/- SE) on Day 11 to 357 +/- 30 and 312 +/- 46 on Days 16 and 21, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
在大鼠妊娠后半期，胎盘为卵巢雌二醇（E2）的产生提供雄激素前体。然而，尚无研究测定妊娠第12天之前或之后循环睾酮（T）或雄烯二酮（A）在体内向E2的合成情况。此外，尚不清楚临近足月时胎盘是否继续作为雄激素的主要来源。因此，我们在妊娠第11、16和21天（足月为第23天）测定了循环中T和A在体内向卵巢E2的转化情况。大鼠（每组N = 6 - 8只）用戊巴比妥麻醉，通过颈静脉开始持续输注[3H]T或[3H]A。60分钟达到同位素平衡后，从对侧颈静脉（J）和子宫 - 卵巢（UO）静脉采集血样，并摘除卵巢。在妊娠第16天的第二组大鼠中，同位素输注开始后，摘除妊娠子宫或双侧卵巢，60分钟后采集血样。通过连续纸层析分离和纯化放射性标记的T、A和E2。在妊娠第16天和21天，输注任一雄激素后，UO静脉中[3H]E2的浓度高于J静脉（p < 0.02），但在妊娠第11天并非如此。在输注[3H]T的动物中，UO静脉中[3H]E2（cpm/ml）从妊娠第11天的84 ± 33（平均值 ± 标准误）分别增加到第16天的357 ± 30和第21天的312 ± 46（p < 0.001）。（摘要截断于250字）
