Inhibition of Prostaglandin-Enhanced Release of LH by Antiserum to Luteinizing Hormone Releasing Hormone

Abstract

Prostaglandin E₂ (PGE₂), PGF_2α, or PGF_2β 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 µg or 20 µg of PGE₂ significantly inhibited the PGE₂-induced rise of plasma LH. Intraventricular infusion of 20 µg of PGF_2αor PGF_2β 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, PGF_2α, and PGF_2β stimulate the release of LH primarily by enhancing the release of LH-RH.