Effect of follicular fluid on the maturation of porcine granulosa cells: stability of luteinization stimulator.

: The effect of follicular fluid on FSH stimulated progesterone secretion and LH/hCG receptor induction was studied in granulosa cells harvested from small porcine follicles. The stability of the stimulatory factor was also assessed. Follicular fluid from large porcine follicles (LFF) added to the culture of granulosa cells in the dilution from 1:32 to 1:3 stimulated progesterone secretion, while at higher concentrations (dilution 1:2 and 1:1) it had an inhibitory effect. In contrast, the influence of follicular fluid on the induction of LH/hCG receptor was stimulatory only in the concentration of LFF diluted from 1:3 to 1:1. When the granulosa cells were cultured with follicular fluid in the absence of pig serum the effect on both progesterone secretion and hCG binding was stimulatory in all the concentrations of follicular fluid tested. Different treatment of follicular fluid (charcoal extraction temperature treatment, lyophilization, dialysis, ethanol precipitation, delipidation and ether extraction) showed that the stimulator of granulosa cell luteinization was not a stable compound.