Acute suppression by PGF2 alpha on LH, epinephrine and fluoride stimulation of adenylate cyclase in rat luteal tissue.

Injection of PGF2 alpha (250 microgram/rat) 15 min prior to isolation of corpora lutea (CL) from PMSG treated immature rats significantly reduced the LH 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 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 micrometer 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 fluoride 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 relation between our results and the LH receptor studies. The proposed mechanism might also explain the transient decrease in epinephrine and fluoride stimulation of AC.