Mechanism of the luteolytic action of prostaglandin F-2 alpha in the rat.
PGF-2 alpha suppresses the LH-induced accumulation of cyclic AMP in young and mature corpora lutea (CL) of pseudopregnant rats, with mature CL being more sensitive. Calcium ions, and later phospholipase C activation, are believed to mediate this effect. In isolated CL of 2 and 10 days of age, depletion of extracellular calcium, or addition of calmodulin inhibitors or of 8-(N,N-diethylamino)-octyl-3,4,5-trimethoxy-benzoate (TMB-8), did not prevent the suppressive effect of PGF-2 alpha. Phorbol 12-myristate 13-acetate augmented, rather than inhibited, the LH-induced cAMP accumulation in young and mature CL. Polyphosphoinositide turnover was stimulated by PGF-2 alpha in young, but not in mature CL. The suppression by PGF-2 alpha of luteal cAMP is therefore apparently not mediated by phospholipase C activation but two phosphodiesterase inhibitors, 3-isobutyl-1-methylxanthine and Ro-20-1724, abolished the inhibitory effect of PGF-2 alpha.
Lahav
M
M
Faculty of Medicine, Technion-Israel Institute of Technology, Haifa.
Davis
J S
JS
Rennert
H
H
D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D012368:4-(3-Butoxy-4-methoxybenzyl)-2-imidazolidinone / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism; D003338:Corpus Luteum / Q000187:drug effects / Q000502:physiology*; D000242:Cyclic AMP / Q000378:metabolism; D015237:Dinoprost / Q000494:pharmacology / Q000502:physiology*; D005260:Female; D007986:Luteinizing Hormone / Q000378:metabolism; D003341:Luteolysis; D011247:Pregnancy; D011374:Progesterone / Q000378:metabolism; D051381:Rats
D012368:4-(3-Butoxy-4-methoxybenzyl)-2-imidazolidinone; D011374:Progesterone; D007986:Luteinizing Hormone; D015237:Dinoprost; D000242:Cyclic AMP; D002118:Calcium; D015056:1-Methyl-3-isobutylxanthine