The Effect of the Chronic Administration of a Potent Luteinizing Hormone Releasing Hormone Analog on the Rat Prostate

Abstract

In order to assess the effect of the chronic administration of a potent luteinizing hormone releasing hormone analog, (D-SER(But)6) LHRH (1–9) nonapeptide-ethylamide (Buserelin, HOE 766) on the pituitary gonadal axis, and the prostate, adult male Wistar rats were administered either 0, 3, 10 or 50μg./kg. body weight Buserelin subcutaneously daily. At 7, 21, 35 and 42 days of treatment, groups of animals were sacrificed and certain serum endocrine and grava metric parameters determined. In addition, at 1, 21 and 42 days of treatment the 1-hour response of serum LH and serum testosterone to a single injection of 10μg./kg. body weight Buserelin was determined.All treatment doses had similar effects. Serum prolactin and the basal and “acute” response of serum LH to Buserelin (+Δ5,000 per cent) were unaltered throughout treatment. Testes weight, testicular LH receptor content, and basal and “acute” concentrations of serum testosterone were markedly decreased by 42 days of treatment (48, 89, 88 and 88 per cent, respectively). Although seminal vesicle weight declined 50 per cent at 42 days of treatment, prostate weight was not altered from initial weight, but was significantly lower than age matched control at 42 days of treatment.Buserelin remains a potent stimulator of pituitary LH release even during chronic administration. It markedly reduces serum testosterone through a predominant testicular site of action. Buserelin treatment inhibits the growth of the normal prostate, but does not cause its regression.