Steroid hormone levels in peritoneal fluid during the periovulatory period

In order to obtain further information on estradiol (E2) and progesterone (P) patterns during the periovulatory period, their levels were determined in peritoneal fluid (PF) and plasma obtained during 22 laparoscopies performed within the 58 hours following the luteinizing hormone surge-initiating rise (LH SIR) determined by plasma LH assays every 6 hours. E2 levels in plasma and PF did not differ before ovulation (n = 13) but differed after ovulation (n = 9, P less than 0.01). P levels were lower in plasma than in PF before ovulation, but there was an overlap of values. After ovulation the difference was significant (P less than 0.01). When plotted as a function of time following LH SIR, E2 levels increases in PF progressively (r = 0.70), whereas the P increase was discontinuous, with a dramatic rise after follicular rupture. These different patterns may be related to respectively divergent and convergent variations of steroid levels in blood and follicular fluid.