Plasma levels of progesterone and cortisol, and urinary pregnanediol excretion, during the post-ovulatory phase of the cycle in normal and ergocornine-treated women

ABSTRACT The plasma level of progesterone in 30 clinically normal women on the estimated 5th to 7th day after ovulation, determined by combined paperand gas-chromatography, was 1.39 μg/100 ml ± 0.14 S. E. The response of eight women to a single oral administration of 2 mg ergocornine methanesulphonate on the estimated 5th, 6th or 7th day after ovulation was examined, in order to evaluate the suggestion that this drug depresses the secretion of steroid hormones by inhibiting 3β-hydroxysteroid dehydrogenase. Plasma progesterone level (μg/100 ml ± S. E,) 5½ h after administration of the drug (0.91 ± 0.15) did not differ significantly from that before treatment (1.0 ± 0.18) or in placebo-treated controls (1.25 ± 0.16 and 1.15 ± 0.14, respectively). Urinary pregnanediol excretion (mg) was similar during the 24 h-period immediately preceding treatment (1.7 ± 0.34) and following it (1.6 ±0.19). The plasma corticoid (11β-hydroxy-Δ 4 -3-ketosteroid) level was reduced by 27.3% ±6.1 S. E. 5½ h after ergocornine administration, but this decline was paralleled by a similar fall (–24.5%) in placebo-treated controls. The results thus provided no evidence for the induction of luteal insufficiency or a specific enzyme block by the alkaloid. The difference from results obtained in rats may be due to species characteristics or dose rate.