EXPRESSION OF RENIN IN COAGULATING GLANDS IS REGULATED BY TESTOSTERONE

Background: The presence of extrarenal or local renin-angiotensin syst em (RAS) has been noted in several tissues, although its functions hav e not yet been clarified. Renin from the coagulating gland (CG) is the most recently discovered local RAS and is a significant subject for i nvestigation because large amounts of both mRNA and proteins are detec ted in this organ. Recently, it has been reported that testosterone in fluences renin synthesis in several extrarenal tissues, although it ha s no effect on intrarenal renin. Therefore, it is possible that CG ren in is also regulated by testosterone. Methods: Forty-four male C57BL/6 mice, aged 3 wk to 6 mo, were used in studies on the ontogeny and and rogen regulation of the RAS in the CG. The tissues were fixed with Bou in's solution and paraffin sections were stained with immunohistochemi cal methods using antirenin antiserum, In each inmunostained section, the relative number of renin-containing cells in terminal portions of the CG were counted. Results: Immunoreactivity for renin was first det ected at 6 wk after birth. After that time, the number of renin-contai ning cells gradually increased throughout the experiment, In adults, s everal patterns of renin immunoreactivity were demonstrated in almost all epithelial cells of CGs, specifically; (1) basolateral granular re action, (2) diffuse immunoreactivity throughout the cytoplasm, and (3) restricted nuclear reaction. Excretory products of some terminal lumi na were also found to be positive for renin, At 10 days after castrati on, renin-containing cells in ductal termini were decreased and remain ed at low levels until at 4 wk after castration. After testosterone in jection, numerical values of renin-containing cells were high at 1 wk and then decreased at 2-3 wk. Conclusion: It is suggested that CG reni n of the mouse is expressed together with sexual maturation during dev elopment and that it depends on the testis, possibly the male sex horm one. (C)1995 Wiley-Liss, Inc.