Effect of addition of human follicular fluid on progesterone secretion by cultured sheep granulosa cells.

The effect of addition of human follicular fluid to cultures of granulosa cells of large sheep follicles (4-6 mm in diameter) on basal and LH-stimulated progesterone secretion was investigated. Both luteinization and progesterone secretion were inhibited by addition of 10% (w/v) charcoal-treated follicular fluid from medium (2-6 mm) and large (7-16 mm) follicles which had low concentrations of estradiol-17 beta, progesterone and LH. In comparison, the fluid from large follicles, having high levels of the same hormones, stimulated both the parameters, and addition of LH along with the fluid had no further effect. Fluid collected from cystic follicles appeared to be stimulatory which also had elevated levels of estradiol-17 beta and progesterone. These findings indicate the presence of both the inhibitors and stimulators of luteinization in human follicular fluid. The effectiveness of any of them either to inhibit or stimulate luteinization probably will depend upon the composition of the follicular fluid and the stage of maturation of the follicles from which it was collected.