Inhibitory Effect of Gossypol
on Basal and Luteinization Factor-Stimulated Progesterone
Synthesis in Porcine Granulosa Cells
J. VRANOVÁ, M. JEŽOVÁ, S.
SCSUKOVÁ, J. KOLENA
Institute of Experimental Endocrinology, Slovak
Academy of Sciences, Bratislava, Slovak Republic
Received September 21, 1998
Accepted November 9, 1998
Summary
Gossypol, a polyphenolic aldehyde, inhibits steroidogenesis and
the reproductive system in both sexes. The present study was
undertaken to investigate whether gossypol may affect
progesterone biosynthesis in cultured porcine granulosa cells
isolated from small (1-2 mm) follicles (SGC). SGC were cultured
with gossypol, NO donor S-nitroso-N-acetylpenicillamine (S-NAP)
or the specific NO-synthase inhibitor N-nitro-L-arginine methyl
ester (L-NAME), in the presence or absence of follicular fluid
isolated from large (5-8 mm) follicles (LFF) or conditioned
media (CM) of granulosa cells isolated from large follicles
(LGC). Gossypol enhanced the nitrite content in culture media of
SGC and inhibited basal progesterone secretion by SGC. S-NAP
(10-3M) inhibited progesterone secretion and enhanced the
formation of cGMP by SGC. L-NAME had no effect on progesterone
accumulation by SGC. The stimulatory effect of LFF or CM media
on progesterone production by SGC in culture was also inhibited
by S-NAP (10-3) and gossypol (10-4M). Moreover, gossypol
inhibited forskolin-stimulated progesterone secretion, as well
as substrate-enhanced conversion of 22-OH-cholesterol and
pregnenolone to progesterone. These results suggest that the
inhibitory effect of gossypol on progesterone secretion in
culture of SGC may be mediated via NO generation.
Key words
Gossypol · Luteinization stimulator · Nitric oxide · Follicular
fluid · Granulosa cell culture
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