The concentrations of progesterone, estrone and estradiol-17β in the peripheral plasma of the rhesus monkey during the final third of gestation, and after the induction of abortion with PGF

John R G Challis, I. John Davies, Kurt Benirschke, Andrew G Hendrickx, Kenneth J. Ryan

Research output: Contribution to journalArticle

17 Scopus citations

Abstract

The concentrations of progesterone, estrone and estradiol-17β have been measured by radioimmunoassay in serial samples of peripheral plasma from rhesus monkeys (Macaca mulatto) during the final third of normal pregnancy, and during the induction of abortion with prostaglandin F (PGF). In 3 out of 5 animals, the plasma progesterone concentration increased during the 5-10 days preceding spontaneous labor. In no animal did the progesterone concentration decrease before parturition. The concentration of estradiol-17β was greater than that of estrone in most plasma samples. The levels of both estrogens in maternal plasma increased within 5 days before parturition, but decreased rapidly after the fetus had been delivered. Daily maternal injections of PGF (10-15 mg/day) administered around day 150 of pregnancy reliably induced premature delivery. The concomitant steroid hormone changes were variable, although most monkeys showed a decline in the plasma progesterone and estrogen levels during the final 24 hr before expulsion of the fetus. The present results support the view that an increase in estrogen production may be an important component of the endocrine control of normal parturition. The pharmacological action of PGF in inducing abortion in the rhesus monkey appears to be different from the mechanisms which effect the spontaneous onset of labor.

Original languageEnglish (US)
Pages (from-to)547-553
Number of pages7
JournalEndocrinology
Volume95
Issue number2
DOIs
StatePublished - 1974

ASJC Scopus subject areas

  • Endocrinology

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