Stimulation of Prostaglandin Accumulation in Preovulatory Rat Follicles by Adenosine 3′,5′-Monophosphate*

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Abstract
LH [luteinzing hormone] stimulates an increase in prostaglandins [PG] in vitro in preovulatory follicles from rats pretreated with PMS [pregnant mare''s serum] gonadotropin. The role of c[cyclic]AMP in this action of LH was examined by incubating preovulatory follicles with various substances and determining the resultant PGE accumulation by radioimmunoassay. LH (5 .mu.g/ml) increased PGE accumulation to approximately 4 times the control (181 .+-. 23 to 886 .+-. 83 pg/follicle). The addition of 20 mM cAMP also stimulated PGE accumulation, and the addition of 20 mM cAMP in the presence of 0.5 mM 1-methyl-3-isobutylxanthine was as effective as LH. Other nucleotides such as ATP, ADP, 3''-AMP, 5''-AMP, cGMP and O2''-monobutyryl-cAMP did not stimulate PGE accumulation. On the other hand, (Bu)2cAMP, 8-bromo-cAMP and N6-monobutyryl-cAMP produced an increase in PGE accumulation similar to that observed with LH. In addition, 10 .mu.g/ml cholera toxin increased both cAMP and PGE accumulation in preovulatory follicles. The PG response of follicles is specific for cAMP-like nucleotides or substances capable of increasing intracellular cAMP. The data support the concept that cAMP mediates the effect of LH on PGE accumulation in preovulatory follicles in the rat.