LUTEINIZING HORMONE (LH) AND PROGESTERONE IN PLASMA AND LH AND OESTROGENS IN URINE DURING 42 NORMAL MENSTRUAL CYCLES

Abstract

ABSTRACT The plasma levels of luteinizing hormone (LH) and progesterone and the urinary excretion of LH and oestrogens were measured during the normal menstrual cycle of 22 young and healthy women. A total of 42 cycles were investigated. The urinary excretion of total oestrogens increased during several days before the rise of LH in the urine. The day of maximum excretion of LH and total oestrogens coincided during the midcycle period. The mid-cyclic rise in LH was found to occur on the same day in the plasma and urine and the days of maximum values coincided in 11 out of 16 cycles. In 5 cycles the maximum level was reached one day later in the urine. The plasma levels of progesterone started to increase during the LH and oestrogen peaks. The days for maximum levels of progesterone coincided with the second peak of urinary oestrogens. The levels of progesterone in the plasma reached values above 10 ng per ml in all normal cycles. The plasma levels of progesterone were below 1 ng per ml plasma when menstrual bleeding started. The length of the luteal phase was 14.4 ± 1.1 (s) days. The sum of daily urinary excretion of total oestrogens and the sum of the daily plasma progesterone levels varied within 15 per cent of the mean in five out of six women studied during more than two cycles. The variation in values for the sums of daily oestrogen excretion and plasma progesterone levels was considerably larger between menstrual cycles of different women than between menstrual cycles of the same woman.