Partial purification from bovine follicular fluid of a factor of low molecular mass with inhibitory effects on the proliferation of bovine granulosa cells in vitro and on rat follicular development in vivo

Bovine follicular fluid was aspirated from follicles of 2-20 mm in diameter, charcoal-treated to remove steroids and then separated into low and high molecular mass fractions. The low molecular mass ( 10 mm) follicles. The inhibitory effect of peak 4 was not due to a toxic effect on cells. Administration of peak 4 to rats did not affect liver or kidney masses but did decrease uterine (25%, P 0.01) and ovarian (35%, P 0.01) masses. Peak 4 also caused a reduction in the number of large follicles (65%, P 0.01) but increased the number of small follicles (55%, P 0.01). We have named the inhibitory factor associated with peak 4, granulosa cell-inhibitory factor (GCIF). The results presented suggest that GCIF may be a factor secreted by dominant follicles that inhibits the development of: subordinate follicles.