Action of luteinizing hormone-releasing hormone and synthesis of prostaglandin in the pituitary gland

Abstract

The possibility that prostaglandin E 2 (PGE 2) may play a role in luteinizing hormone (LH) release was examined using an in vitro model. Addition of luteinizing hormone-releasing hormone (LH-RH) to the culture medium stimulated cyclic AMP accumulation and LH-release by incubated hemipituitaries, but did not affect the level of PGE 2 or prostaglandin synthetase activity in the gland. Aspirin and indomethacin reduced both prostaglandin synthetase activity and PGE 2 content in the pituitary, but did not impair the stimulatory action of LH-RH on either cyclic AMP accumulation or LH-release. Flufenamic acid on its own caused LH-release, but the drug abolished the effect of LH-RH on cyclic AMP accumulation. The mechanism of this action of flufenamic acid is not understood. It is concluded that the stimulatory action of LH-RH on pituitary cyclic AMP production and LH release is not mediated by prostaglandins.