Localization of metallothionein in the genital organs of the male rat.

Abstract

We studied the immunohistological localization of metallothionein (MT), a low molecular weight metal binding protein, in male rat genital organs (testis, epididymis, ejaculatory duct, seminal vesicle, coagulating gland, and prostate) by use of the avidin-biotin-peroxidase complex method. MT concentrations in testis, seminal vesicle, and prostate ranged from 15-30 micrograms/g tissue. In testis, seminiferous tubules with mature spermatozoa exhibited weak MT staining, whereas the tubules containing differentiating spermatogenic cells but not containing spermatozoa showed strong MT staining. No MT immunostaining was observed in Leydig cells. In growing rat testes, the pattern of MT immunostaining was found to change with development: MT was found in supporting cells only on Day 7, spermatogonia adjacent to basement membrane on Day 14, and spermatocytes localized in the central part of the tubules on Day 21. Strong MT immunostaining in the basal cells was a common feature in other genital tissues, except the ductus efferentes. In prostate, the strongest MT staining was found in the lateral lobe, and MT was localized in apocrine secretions in the dorsal lobe. The present results suggest a close association of MT with cell proliferation and differentiation, as well as possible involvement of MT in supply or storage of zinc ions.

Immunohistochemical demonstration of metallothionein in human male excretory ducts of the testis.

“…MT was identified in human, rat, and rabbit prostate (2,10,13,14), and in the testis of rat and mouse (3,8). In the human prostate, MT concentration was the highest in the peripheral zone of normal prostate gland; MT was secreted from the prostatic epithelial cells into the prostatic fluids, which form a part of the seminal fluids, and it has been suggested that MT interacts with the sperm (10,11).…”

“…In the human prostate, MT concentration was the highest in the peripheral zone of normal prostate gland; MT was secreted from the prostatic epithelial cells into the prostatic fluids, which form a part of the seminal fluids, and it has been suggested that MT interacts with the sperm (10,11). Using Northern blotting and in situ hybridization, the localization of MT mRNA in the testis was observed in the primary spermatocytes and round spermatids, but not in Sertoli cells, interstitial cells, or in tailed spermatozoa of mice the role of MT in the male reproductive tracts, especially the excretory ducts of the testis, has not been studied in detail (8).…”

“…There are few reports of MT in the epididymis (8), and the localization of MT was observed in some ed by means of adding a large amount of MT antigen to the primary antibody. This finding suggests that MT was secreted from the principal cells in the epididymal tail.…”

“…It is unique in its ability to bind class II-B metals, such as zinc, and has been identified in the seminiferous tubules and prostate (3,8,10,13). MT was also shown to secrete in the prostatic fluid and was thought to interact with mature sperm (11), but the role of MT in the human male reproductive tract, especially in the epididymis, has not yet been elucidated.…”

Binding of Metallothionein to Rat Spermatozoa.

“…Nishimura et al (1990) reported that MT was localized in the nucleus of rat sperm in the testis by an immunohistochemical study. Also, the level of MT mRNA is maintained at a high level in the spermatid in the mouse, but that in the mature sperm cells it is low (De et al 1991).…”