A biochemical test for the direct assessment of endometrial function: Measurement of the major secretory endometrial protein PP14 in serum during menstruation in relation to ovulation and luteal function

Circulating PP14 was measured by radioimmunoassay in ovulating (n = 12) and anovulatory (n = 3) women throughout the menstrual cycle, the highest levels of serum PP14 being seen during menstruation and in the late luteal phase in ovulating women. Mean serum PP14 levels on days 1-7 and 24-28 of the menstrual cycle were significantly higher than those observed from days 8 to 23 (P <0.0005 and P = 0.005 respectively). There was no difference in mean PP14 levels observed in the menstrual and luteal phase. By contrast, serum PP14 was rarely detected in anovulatory cycles. During the luteal phase, mean serum PP14 levels were apparently not related to serum progesterone levels. However, mean PP14 levels during the menstrual phase were significantly higher in the group of women with the highest progesterone production (P(max) > 39 nmol/l) (P <0.002) in comparison with levels seen in ovulating women with lower progesterone production (P(max) <32 nmol/l). These findings suggest that the synthesis and secretion of PP14 is influenced by ovulation and luteal function. Serum PP14 measurements may provide useful information about the endometrium in relation to fertility, and that these measurements during the menstrual cycle may distinguish between ovulatory and anovulatory cycles.