while preincubation with EGF also
reduced steroid synthesis by hCG and TPA, but not db-cAMP. Interestingly,
the degree of EGF-mediated down-regulation of LHR
(ca. 30%) roughly corresponds to the reduction in the degree of
hCG-mediated steroidogenesis in these cells (ca. 20%), and the
degree of TPA-mediated down-regulation of EGFR (about 65%)
correlates with the reduction in the ability of EGF to stimulate
steroidogenesis (ca. 60%)