Endothelin-1 and Endothelin-3 Stimulate Prostaglandin E₂ Secretion from the Rat Median Eminence

Abstract

The in vitro effects of endothelin-1 (ET-1) and endothelin-3 (ET-3) on the release of prostaglandin (PG) E₂ from the rat median eminence were investigated. The addition of ET-1 from 10^-9M to 10^-6M stimulated PGE₂ release in a dose-dependent manner (from 10.5±2.1 to 54.4±5.6pg/ME fragment/ 30 min; mean±SEM, p<0.001). ET-3 also stimulated the release of PGE₂ from 10^-7 M to 10^-5 M dose dependently (from 18.1±0.7 to 60.9± 17.4pg/ME fragment/30 min p<0.05). The time course effect of ET-3 (10-6 M) showed that PGE₂ release was stimulated within five minutes (control, 1.5±0.5; ET-3, 15.8±3.0pg/ME fragment/5 min, p<0.01). These results suggest that ET-1 and ET-3 have some physiological effects on the rat median eminence.