Androgen-dependent synthesis secretion of caltrin, calcium transport inhibitor protein of mammalian seminal vesicle

Effects of androgen status on the synthesis and secretion of rat caltrin ha ve been studied by three different procedures: a) immunocytochemistry in se minal vesicle tissues; b) polyacrylamide gel electrophoresis and Western im munostaining of seminal vesicle secretion; and c) evaluation of trypsin inh ibitory activity of the seminal vesicle secretion. Rat caltrin has been imm unolocalized in cells of the secretory epithelium, specifically in the elec tron-lucent halo of secretory granules which store and transport proteins t o the lumen. No caltrin immunoreaction was detected 14 days postcastration, and the ultrastructure of the epithelial cells was markedly altered. SDS-P AGE and Western blotting of the seminal vesicle secretion revealed alterati ons in the protein pattern and loss of the caltrin-related immunoreactive b ands. The 54-kDa caltrin-precursor protein and the 6.2-kDa active caltrin w ere absent. Trypsin inhibitory activity of the seminal secretion was reduce d about 50% in castrated animals. Daily testosterone administration restore d both the protein pattern and immunoreactivity of the seminal vesicle secr etion, and, as expected, reversed the morphological alterations of the glan d after 7 days of treatment. Trypsin inhibitor effect of the secretion also returned to normal levels after fourteen days of testosterone administrati on. Data suggest that the synthesis and secretion of caltrin are testostero ne-dependent processes.