Secretion of proteins and glycoproteins by perifused rabbit corpus epididymal tubules: Effect of castration

Abstract

Protein synthesis in epididymal tissue of intact and castrated rabbits was studied after incubation of epididymal minces with [35S]-cysteine or [35S]-methionine and protein separation by two-dimensional gel electrophoresis. Regional differences in the pattern of protein synthesized were observed. Castration did not change overall protein synthesis, but it reduced these regional differences. The presence of 5 alpha-DHT in the culture medium of the proximal corpus epididymidis perfused for 24 hr did not increase overall protein synthesis in tubules from intact or castrated rabbits and did not reinitiate synthesis of the proteins that had disappeared after castration. The kinetics of glycoprotein synthesis and secretion were studied by light and electron microscopy autoradiography at 0.5, 2, 6, and 24 hr after exposure to [3H]-mannose, [3H]-fucose, and [3H]-glucosamine. Changes in the distribution of mannose- and glucosamine-labeled material indicated that the decline in grain density over the epithelium from 30 min to 24 hr coincided with an increasing reaction over the stereocilia border from 30 min to 2 hr and in the lumen from 2 to 24 hr. The distribution of fucose-labeled material indicated that the grain reaction over the epithelium declined more rapidly than with the mannose label. When the glucosamine-labeled sperm mass was released from the tubules, the labeled material was lost after the first washing, indicating that the glucosamine-labeled glycoproteins did not bind firmly to corpus spermatozoa within 24 hr. After castration, both mannose- and fucose-labeled materials migrated to the cell apex more rapidly than in the intact animal, but they were not released as readily into the lumen. The culture of epididymal tubules from castrated males with 5 alpha-DHT for 24 hr did not promote the release of either mannose- or fucose-labeled material into the lumen. However, testosterone given in vivo for 2 weeks restored secretion of mannose-labeled material into the lumen.

Castration induces changes in the cation‐dependent mannose‐6‐phosphate receptor in rat epididymis: Possible implications in secretion of lysosomal enzymes

“…An important aspect of epididymal sperm maturation and storage seems to be the interaction of luminal proteins with the surface of spermatozoa [Brooks, 1987;Orgebin-Crist et al, 1987;Hinton et al, 1995;Kirchhoff, 1998]. Therefore, the epididymis of mammals can be studied in different angles: as an organ involved in the maturation of sperm, as a model to study secretory activity, and as an organ responsive to steroidal hormones.…”

Effects of cyproterone acetate on the ultrastructure of the human epididymis

“…So, the threshold requirement of androgen to maintain the structural and functional integrity of the epididymis in the rat, hamster, and monkey is much higher than that needed by the accessory glands (Rajalakshmi et al, 1975). Orgebin-Crist et al (1987) have reported that although the pattern of newly synthesized proteins is not affected in the short term by the presence or absence of androgens in the culture medium of epididymal tubules from intact rabbit, some specific proteins of the caput and corpus epididymidis appeared to be more androgendependent than the cauda epididymidis proteins, with the result that the regional differences in the electrophoretic pattern of normal animals disappear in those castrated.…”

“…It is well known that the functional integrity of the epididymis is androgen-dependent (Blaquier et al, 1972;Orgebin-Crist et al, 1975;Brooks, 1983;Wolf, 1986). There is evidence that sperm maturation will not occur in epididymal tubules cultured in vitro, if androgen dependent proteinsynthesis is blocked by antiandrogen or by inhibitors of RNA or protein synthesis (Orgebin-Crist & Jahad, 1978.…”

“…Since androgen withdrawal results in a rapid loss of the viability of spermatozoa within a few days, the short and long term Correspondence: Professor Maria Luisa L6pez A,, Departamento de Biologia Celular y GenCtica, Facultad de Medicina, Universidad de Chile, Casilla 70061, Correo 7, Santiago, Chile. effects of castration or hypophysectomy on the biochemistry and morphology of the epididymis have also been studied (Brooks 1976;Moore & Bedford, 1979;Orgebin-Crist et al, 1987).…”

Lysosomal integral membrane proteins exhibit region and cell type specific distribution in the epididymis of the adult rat

“…In cultured cells, the general immunostaining patterns observed in vivo were maintained during the duration of the primary cultures for all five LIMPs. Our results begin to address the molecular heterogeneity of the lysosomal system along the length of the epidiymis, and may suggest in part a basis for underlying structural and functional characteristics of the epididymis leading to the sequential maturation of sperm.The functions of the epididymis include storage, transport, and provision of a post-testicular site for the maturation of spermatozoa (Bedford, 1975;Hamilton, 1975;Cooper, 1986;Orgebin-Crist, et al, 1987;Robaire and Hermo, 1988). A means by which the epididymis accomplishes these functions is to generate a special luminal fluid that "conditions" the spermatozoa.…”