The present studies were conducted to determine whether prostaglandin F(2α) (PGF(2α)) stimulates the production of 'second messengers' derived from inositol phospholipid hydrolysis and increases intracellular free Ca2+ ([Ca2+](i)) in isolated bovine luteal cells. PGF(2α) provoked rapid (10 sec) and sustained (up to 60 min) increases in the levels of inositol mono-, bis-, and trisphosphates (InsP, InsP2, and InsP3, respectively). InsP3 was formed more rapidly than InsP2 or InsP after PGF(2α) treatment. In addition, PGF(2α) increased inositol phosphpholipid turnover, as evidenced by increased 32PO4 incorporation into phosphatidic acid and phosphatidyl-inositol. LiCl (1-20 mM) enhanced inositol phosphate accumulation in response to PGF(2α). Maximal increases in InsP3 occurred at 1 μM PGF(2α), with half-maximal stimulation occurring at 36 nM. The acute effects of PGF(2α) on InsP3 levels were independent of reductions in extracellular calcium. Prostaglandins E1 and E2 also stimulated increases in inositol phosphate levels, albeit to a lesser extent. PGF(2α) also induced rapid and concentration-dependent increases in [Ca2+](i) as measured by quin-2 fluorescence. The PGF(2α)-induced increases in [Ca2+](i) were maximal within 30 sec (approximately 2- to 3-fold), and [Ca2+](i) remained elevated for 8-10 min. The PGF(2α)-induced increases in [Ca2+](i) were also independent of extracellular calcium. These findings demonstrate that the action of PGF(2α) is coupled to the phospholipase C-InsP3 and diacylglycerol second messenger system in the corpus luteum.
|Original language||English (US)|
|Number of pages||5|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|State||Published - 1987|
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