Activity of a human follicular fluid protein(s) in spontaneous and induced ovarian cycles

Recently, we identified a human follicular fluid protein(s) (FP) which inhibited human menopausal gonadotropin (hMG)-induced rat ovarian weight gain and FSH-induced aromatase. Here, we assessed FP activity from ovulatory patients who were either untreated (n = 7) or received clomiphene (n = 9; 150 mg/day on cycle days 5-9) or hMG (n = 6; 150 IU/day on cycle day 3). Aspirations were performed when one follicular diameter exceeded 20 mm. FP activity was expressed as the percent inhibition of porcine granulosa cell aromatase activity at three concentrations of extracted follicular fluid (range, 1250-10 micrograms; extrapolated to 50 micrograms). Patients receiving hMG or clomiphene had multiple follicles greater than 16 mm in diameter (3.83; 2.66/patient, respectively), while untreated patients had 1 each. FP activity was 14.1 +/- 5.3% (mean +/- SEM) inhibition for untreated, 18.0 +/- 3.4% inhibition for hMG-treated, and 13.7 +/- 5.3% inhibition for clomiphene-treated patients. Follicular fluid estradiol levels from untreated patients (2590 +/- 1221 ng/ml) were greater than estradiol concentrations from hMG-treated (356 +/- 55 ng/ml; P less than 0.01) or clomiphene-treated (1317 +/- 344 ng/ml; P less than 0.05) patients. Progesterone follicular fluid levels were 9.84 +/- 3.3, 5.18 +/- 61, and 11.3 +/- 2.3 micrograms/ml for untreated, hMG-treated, and clomiphene-treated patients, respectively (P less than 0.05). A similar relationship was present with 17-hydroxyprogesterone (untreated, 1.6 +/- 0.2 micrograms/ml; hMG-treated, 0.76 +/- 0.1 micrograms/ml; clomiphene-treated, 2.16 +/- 0.3 micrograms/ml; P less than 0.05). Androstenedione and testosterone follicular fluid levels were similar in all groups (78.9 +/- 23 and 7.09 +/- 2.14 ng/ml, respectively). Untreated patients had a positive correlation between FP and follicular fluid estradiol (r = 0.689; P less than 0.01) and inhibin activity (r = 0.654; P less than 0.05), and a negative correlation between follicular fluid progesterone levels (r = 0.622; P less than 0.05). Patients treated with hMG had a significant negative correlation between FP activity and follicular fluid progesterone levels (r = 0.756; P less than 0.005) and a biphasic correlation with follicular fluid 17-hydroxyprogesterone (r2 = 0.853; P less than 0.0025). Clomiphene-treated patients had biphasic correlations between follicular fluid estradiol and 17-hydroxyprogesterone levels (r2 = 0.853 and P less than 0.0025, and r2 = 0.637 and P less than 0.025, respectively). These findings indicate that the FP activity of the dominant follicle correlates with its state of differentiation, as described by intrafollicular estradiol, progesterone, 17-hydroxyprogesterone levels and inhibin activity. These relationships are in part dependent upon gonadotropin stimulation.