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Effects of phorbol esters on steroidogenesis in small bovine luteal cells
Author(s) -
Benhaim Annie,
Herrou Michel,
Mittre Herve,
Leymarie Pierre
Publication year - 1987
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(87)80312-5
Subject(s) - protein kinase c , medicine , activator (genetics) , endocrinology , phorbol , diacylglycerol kinase , protein kinase a , luteal phase , chemistry , in vitro , stimulation , receptor , biology , signal transduction , kinase , biochemistry , hormone
The possible influence of an activator of protein kinase C, the tumor‐promoting phorbol ester, PMA (phorbol‐12‐myristate‐13‐acetate), upon small bovine luteal cell steroidogenesis was investigated in vitro. PMA had no significant effect on basal and dibutyryl cyclic AMP (dbcAMP)‐stimulated progesterone production but markedly modulated the LH‐stimulated progesterone and cAMP productions. PMA potentiated the LH‐stimulated cAMP accumulation whatever the dose of LH used. It also potentiated the LH‐induced progesterone production in the presence of low doses of LH. Paradoxically, in the presence of maximal or submaximal effective doses of LH, PMA exerted a time‐ and dose‐dependent inhibition of progesterone synthesis. Diacylglycerol was able to mimic the effects of PMA on LH‐induced steroidogenesis. These observations suggest that the Ca 2+ ‐ and phospholipid‐dependent protein kinase C can modulate the regulation by LH of small bovine luteal cell steroidogenesis at a step before the synthesis of cAMP. They also suggest that the interaction between LH and its receptor is able to trigger a negative regulatory signal which would be only expressed for high doses of LH and in the presence of an activator of PKC.