ACUTE SUPPRESSION BY PGF 2-ALPHA ON LH, EPINEPHRINE AND FLUORIDE STIMULATION OF ADENYLATE-CYCLASE IN RAT LUTEAL TISSUE

  • 1 January 1979
    • journal article
    • research article
    • Vol. 5  (1) , 55-63
Abstract
Injection of PG[prostaglandin]F2.alpha. (250 .mu.g/rat) 15 min prior to isolation of corpora lutea (CL) from PMSG [pregnant mares serum gonadotropin] treated immature rats significantly reduced the LH [lutropin] stimulation of adenylate cyclase in CL membranes. The LH stimulation did not return to normal even 24 h after PGF2.alpha. injection. A transient decrease in epinephrine and fluoride stimulation of AC [adenylate cyclase] was also observed, the response returning to normal 6-12 h after PGF2.alpha. treatment. In vitro incubation of whole isolated CL with 0.005 .mu.M or higher concentrations of PGF2.alpha. markedly reduced the LH and fluoride stimulation of AC in the CL membranes. Exposure of CL to PGF2.alpha. for 15 min in vitro reduced the LH and F- response. The results are discussed in relation to the suppressive action of PGF2.alpha. on LH receptors in CL and a mechanism is proposed to explain the discrepancy in time realtion between the results and the LH receptor studies. The proposed mechanism might also explain the transient decrease in epinephrine and F- stimulation of AC.

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