Effect of castration on eicosanoid and catecholamine-induced luteinizing hormone-releasing hormone release in vitro

Abstract

The castraction of adult rats four weeks before experimentation did not alter either the basal production of prostaglandin (PG) E 2 (intract rats 1157 ± 160pg/mg protein, castrated rats 1093 ± 90 pg/mg protein) or the A 23187-induced production of PGE 2 (1591 ± 209 or 1701 ± 289 pg/mg protein respectively) or that of leucotriene (LT) C 4 (474 ± 33, 389 ± 39 pg/mg protein). Castration significantly reduced the absolute amounts of luteinizing hormone-releasing hormone (LHRH) relased under basal conditions (594 ± 56 pg/mg protein to 34% of intact controls) and after A 23187 stimulation (to 28% of controls). The LHRH released by the median eminence (ME) in castrated rats in the presence of PGE 2 (10 −6M), LTC 4 (10 −8M), norepinephrine (NE) (10 −5M) or dopamine (DA) (10 −5M and 10 −4M) was significnatly lower than the LHRH released by intact animals in the presence of these factors. However the relative values for LHRH relase (e.g. as % of controls) indicated that the degree of stimulation was identical in intact and castrated rats (2–3 times). These data suggest that the absence of gonadal steroid resulting from long-term castration does not block the stimulatory action of eicosanoids or catecholamines on the release of LHRH by the ME of adult male rats in vitro. Furthermore, castration does not intergere with the biosynthesis of PGE 2 and LTC 4.