MODULATION OF THE EFFECTS OF FSH, ANDROSTENEDIONE, EPIDERMAL GROWTH-FACTOR (EGF) AND INSULIN-LIKE GROWTH-FACTOR-I (IGF-I) ON BOVINE GRANULOSA-CELLS BY GCIF, A GROWTH-INHIBITORY FACTOR OF LOW-MOLECULAR-MASS FROM BOVINE FOLLICULAR-FLUID
Ac. Hynes et al., MODULATION OF THE EFFECTS OF FSH, ANDROSTENEDIONE, EPIDERMAL GROWTH-FACTOR (EGF) AND INSULIN-LIKE GROWTH-FACTOR-I (IGF-I) ON BOVINE GRANULOSA-CELLS BY GCIF, A GROWTH-INHIBITORY FACTOR OF LOW-MOLECULAR-MASS FROM BOVINE FOLLICULAR-FLUID, Journal of Reproduction and Fertility, 108(2), 1996, pp. 193-197
A granulosa cell-inhibitory factor (GCIF) of low molecular mass from b
ovine follicular fluid inhibits the proliferation of bovine granulosa
cells in vitro and the growth of large follicles in rats in vivo. The
present study examined the ability of GCIF to modulate the effects of
FSH, epidermal growth factor (EGF), insulin-like growth factor I(IGF-I
) and androstenedione on the proliferation of bovine granulosa cells a
nd on aromatase activity in vitro. Granulosa cell proliferation was as
sayed by counting haemocytometric cells and by measuring the incorpora
tion of [H-3]thymidine into acid-precipitable material. Assay of aroma
tase activity was based on the conversion of [H-3]androstenedione to [
H-3]H2O. FSH, androstenedione, EGF and IGF-I all stimulated (P < 0.01)
granulosa cell proliferation; however, the addition of GCIF reduced (
P < 0.01) cell proliferation in their presence. In the case of EGF, th
e addition of GCIF almost abolished the stimulatory response. FSH and
IGF-I, but not EGF, stimulated (P < 0.01) aromatase activity of granul
osa cells. The stimulatory effect of IGF-I was decreased by GCIF. The
inhibitory effects of GCIF indicate that it may play a significant rol
e in regulating the effects of intraovarian growth factors on granulos
a cells and the growth of follicles.