Inhibition of prostaglandin-enhanced release of LH by antiserum to luteinizing hormone releasing hormone

Prostaglandin E2 (PGE2), PGF2alpha, PGF2beta was infused into a lateral ventricle of the brain of adult male rats, after pretreatment with normal rabbit serum (NRS) or anti-LH-RH serum, and the concentration of LH in arterial plasma was determined. I.v. administration of anti-LH-RH serum 2.5 min prior to the infusion of 2 microgram or 20 microgram of PGE2 significantly inhibited the PGE2-induced rise of plasma LH. Intraventricular infusion of 20 microgram of PGF2alpha or PGF2beta into NRS-pretreated animals caused a marked increase in the plasma LH concentration; whereas, prior i.v. administration of anti-LH-RH serum blocked the PG-induced rise in plasma LH levels. It is concluded that PGE2, PGF2alpha, and PGF2beta stimulate the release of LH primarily by enhancing the release of LH-RH.