Fr. Tekpetey et al., DIFFERENTIAL MODULATION OF PORCINE THECA, GRANULOSA, AND LUTEAL CELL STEROIDOGENESIS INVITRO BY TUMOR-NECROSIS-FACTOR, Biology of reproduction, 48(4), 1993, pp. 936-943
The role of tumor necrosis factor alpha (TNFalpha) in ovarian function
was investigated using in vitro culture of theca and granulosa cells
isolated from gilt follicles (4-6 mm) and small (SLC) and large (LLC)
luteal cells from mid-cycle corpora lutea. TNFalpha did not affect bas
al accumulation of progesterone (P) by theca cells after 72 h of cultu
re. However, TNFalpha (0. 1 - 100 ng/ml) caused a marked dose-dependen
t noncytotoxic inhibition (p < 0.05) of LH or LH + insulin (I)-stimula
ted P accumulation by theca cells after 72 h. Maximal inhibitions aver
aged 87 +/- 6% at 5 ng/ml TNFalpha for LH-stimulated P and 69 +/- 4% a
t 50 ng/ml TNFalpha for LH + I-stimulated P. The inhibitory effect of
TNFalpha, evident by 24 h after culture, progressively increased on Da
ys 2 and 3 of culture. The effect of TNFalpha on theca cells was media
ted by cAMP generation as evidenced by TNFalpha inhibition of LH-induc
ed cAMP accumulation and P accumulation in response to LH and forskoli
n but not dibutyryl cAMP. Consistent with this, TNFalpha had no effect
on increased P accumulation by theca cells in the presence of 22-hydr
oxycholesterol or pregnenolone alone, but inhibited further increases
in P accumulation stimulated by LH plus sterol substrates. Unlike that
in theca cells, FSH-induced P accumulation in granulosa cell cultures
was slightly enhanced (p < 0.05) by low doses of TNFalpha (0. 1, 0. 5
, and 1.0 ng/ml) after 72 h, while higher doses (5-50 ng/ml) did not a
lter P accumulation. Furthermore, in experiments with luteal cells, TN
Falpha had no effect on P accumulation in cultures of SLC or LLC after
36 h. The effect of INFalpha on porcine theca cells may indicate a ro
le in preventing premature follicular luteinization; together with pre
vious evidence, this suggests a complex and possibly evolving physiolo
gical role for TNFalpha during follicular development.