PROGESTERONE LEVELS IN PERIPHERAL PLASMA DURING THE LUTEAL PHASE OF THE NORMAL HUMAN MENSTRUAL CYCLE MEASURED BY A RAPID COMPETITIVE PROTEIN BINDING TECHNIQUE

TLDR

The assay uses only 0.25 ml of plasma and was applied to 20 normal menstrual cycles. The rapid competitive protein binding technique, capable of assaying 20 samples per day with good precision and accuracy, showed that progesterone rises to a 10–20 ng/ml plateau 4–6 days after the estrogen peak before falling below 1 ng/ml at menses, with a mean luteal phase of 14.15 days.

Abstract

ABSTRACT The competitive protein binding technique for the measurement of progesterone has been further simplified for clinical use. Only 0.25 ml of plasma is needed for the determination during the luteal phase. One technician can assay 20 samples in one day with good precision and accuracy. The progesterone concentration in 20 normal human menstrual cycles was studied. During the follicular phase a mean concentration of 0.32 ± 0.25 ( s ) ng/ml plasma was found. At the mid-cycle peak of the total oestrogens the progesterone concentration started to rise and reached a plateau between 10–20 ng/ml 4 to 6 days later. From the plateau level, the concentration fell rapidly to less than 1 ng/ml at the onset of menstrual bleeding. The mean luteal phase lasted for 14.15 ± 1.05 ( s ) days.