J. Vranova et al., Inhibitory effect of gossypol on basal and luteinization factor-stimulatedprogesterone synthesis in porcine granulosa cells, PHYSL RES, 48(2), 1999, pp. 119-128
Gossypol, a polyphenolic aldehyde, inhibits steroidogenesis and the reprodu
ctive 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 cult
ured with gossypol, NO donor S-nitroso-N-acetylpenicillamine (S-NAP) or the
specific NO-synthase inhibitor N-nitro-L-arginine methyl eater (L-NAME), i
n 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 med
ia of SGC and inhibited basal progesterone secretion by SGC, S-NAP (10(-3)M
) inhibited progesterone secretion and enhanced the formation of cGMP by SG
C. L-NAME had no effect on progesterone accumulation by SGC. The stimulator
y effect of LFF or CM media on progesterone production by SGC in culture wa
s also inhibited by S-NAP (10(-3)) and gossypol (10(-4)M). Moreover, gossyp
ol inhibited forskolin-stimulated progesterone secretion, as well as substr
ate-enhanced conversion of 22-OH-cholesterol and pregnenolone to progestero
ne. These results suggest that the inhibitory effect of gossypol on progest
erone secretion in culture of SGC may be mediated via NO generation.