Concentrations of follicle regulatory protein, steroids and gonadotrophins in antral fluids from women stimulated with metrodin and hCG.
Concentrations of immunoreactive follicle regulatory protein (FRP) were determined in 184 follicular fluid samples recovered from 30 patients in whom ovarian stimulation before oocyte recovery and in-vitro fertilization was induced with FSH (150 i.u./day). Ovum recovery was scheduled when the diameters of greater than or equal to 2 follicles reached 15-17 mm and serum oestradiol values were 740 pM/follicle. The mean level of FRP in fluid from follicles yielding oocytes which fertilized and cleaved within 48 h of recovery (24.4 +/- 3.08 immunoreactive units [IRU]/ml; 1 IRU = approximately 1 ng pig FRP) was higher than that in fluid from follicles yielding oocytes which did not fertilize (10.5 +/- 1.67 IRU/ml, P less than 0.05). FRP in fluid from follicles yielding oocytes which fertilized but did not cleave within 48 h of recovery was 17.2 +/- 2.89 IRU/ml. Overall, concentrations of FRP did not correlate with follicular fluid volume or with FSH or LH concentrations, but were positively related to prolactin, oestradiol and total protein levels (P less than 0.04). The results indicate that the FRP content of follicular fluid may be predictive of follicle/oocyte maturity. A dose-dependent increase in release of FRP by pig granulosa cells cultured in medium supplemented with 10-100 ng prolactin/ml was demonstrated. Prolactin may, therefore, be an important determinant of FRP production by granulosa cells.