MATERNAL AND FETAL PRODUCTION-RATES OF PROGESTERONE IN RHESUS MACAQUES - PLACENTAL-TRANSFER AND CONVERSION TO CORTISOL
MATERNAL AND FETAL PRODUCTION-RATES OF PROGESTERONE IN RHESUS MACAQUES - PLACENTAL-TRANSFER AND CONVERSION TO CORTISOL
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DOI：
10.1210/endo-117-3-1253
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发表时间：
1985-01-01
期刊：
影响因子：
4.8
通讯作者：
NOVY, MJ
中科院分区：
文献类型：
--
作者：
DUCSAY, CA;STANCZYK, FZ;NOVY, MJ
Maternal and fetal progesterone (P4) metabolism and placental transfer were examined in vivo. Via a femoral vein, 3.2 .mu.Ci [14C]P4 were infused at a constant rate for 2 h into 5 rhesus macaques on days 131-137 of gestation. Simultaneously, 12 .mu.Ci [3H]P4 were infused into the fetuses via a placental bridging vein. Measurement of steady state concentrations of [14C]- and [3H]P4 in the maternal and fetal circulations permitted calculation of the MCR [metabolic clearance rates] production rates (PR), and transfer rates (V) of P4. The maternal MCR (533 l/day) was higher than the fetal MCR (93 l/day), whereas the maternal PR did not differ significantly from the fetal PR (2.3 and 1.0 mg/day, respectively). Placental transfer of P4 from the fetal to maternal circulation (VFM) was greater than that from the maternal to fetal circulation (VMF). Values were 0.23 and 0.07 mg/day, respectively. The utilization of circulating P4 as a substrate for fetal cortisol (F) production was examined in 3 additional monkeys for whom the amount of isotopically labeled P4 infusate was increased 5-fold. By determining the ratio of specific activities of [3H]F and [3H]P4 in the fetal circulation, the maximum contribution of circulating fetal P4 as a precursor of fetal F was was found to be < 1%. Higher fetal than maternal plasma P4 concentrations (11.3 and 4.3 ng/ml, respectively) are most likely the result of 5-fold lower fetal MCR, since the PR are similar in the fetal and maternal compartments, and the VFM is greater than the VMF. Fetal F production using circulating P4 as a substrate is minimal.
