Effect of Chronic Removal of Testicular Fluid on the Release of Follicle-Stimulating Hormone in Hemicastrated Rams

Abstract

Department of Physiology & Biochemistry, The University, Whiteknights, Reading, RG6 2AJ (Received 29 November 1977) Testicular fluid (RTF) collected from rams in this laboratory has been shown to contain 'inhibin', which selectively inhibits the release of follicle-stimulating hormone (FSH) in rats (Franchimont, Chari, Hazee-Hagelstein, Debruche & Duraiswami, 1977). During these collections, the possibility that diversion of RTF from the remaining testis of hemicastrated rams might provide further evidence about the feedback control of FSH was examined. Eight mature Clun Forest rams, hemicastrated at least 3 months previously, were placed in metabolism crates in a room with natural lighting for 7 days, after which the extratesticular rete of the remaining testis was cannulated (Voglmayr, Scott, Setchell & Waites, 1967) under general anaesthesia. Each ram was returned to its crate, where it was supported by a canvas harness during the collection of RTF (Edwards, Dacheux & Waites, 1976). The operations were performed

The role of testicular fluid on blood plasma levels of FSH and LH in the ram (1)

“…Since this substance is known to regulate FSH and LH in the ram (Blanc et al, 1978 ;Cahoreau et al, 1979), we were interested to know whether the RTF has a regulatory role on the level of gonadotrophins in the peripheral blood of the adult ram, or whether, since testicular lymph is known to contain inhibin activity (Eddie et al, 1977 ;Baker et al, 1978), this role might be relevant to the inhibin secreted by the Sertoli cells into the extratubular compartment of the testis and drained through the lymphatic vessels to the blood stream. Such an hypothesis has been also postulated by Cahoreau et al (1977) In the same rams, removal of the remaining testis resulted in a significant and sharp increase of blood LH and FSH from the day after castration onwards, ending in a 5-fold and 9-fold increase, respectively, 7 days after orchidectomy, and a small decrease of testosterone : 0.5 versus 1.4 ng/ml after vs before castration ( fig.1d, e, f (Voglmayr et al, 1967 ;Walton et al, 1978 : in which the mean daily sperm production of hemicastrated rams, 4.6 ! 0.34 x 10!, is similar to that observed in the present work ; Cahoreau et 0 1., 1979).…”

Functional Relationships of the Mammalian Testis and Epididymis

“…Like ABP, inhibin must also be secreted into the general circulation either via testicular lymph or directly into spermatic venous blood, because secretion only into rete testis fluid inside the BTB would lead to problems of delivery to the pituitary gland. Indeed, diversion of rete testis fluid out of rams did not lead to an alteration in the concentration of circulating FSH (Walton et al 1978a), indicating that another route of secretion existed (Fig. 2).…”