Rat Sertoli cell clusterin, α2-macroglobulin, and testins: Biosynthesis and differential regulation by germ cells

摘要: Abstract Clusterin, α 2 - macroglobulin and testins are three novel Sertoli cell proteins whose physiological functions may be related to cell-cell interactions in the seminiferous epithelium of testis. We have demonstrated biosynthesis clusterin, , by cells vitro using pulse-chase labeling analysis. For two precursors with an apparent molecular weight ( M r ) 72,000 (PH) 66,000 (PL) were detected cytosol addition 43,000) β 35,000) subunits mature protein. However, not secreted into medium since only clusterin detected. testins, no precursor molecules either or culture medium. The polarized secretory pattern these their regulation follicle stimulating hormone (FSH) testosterone (T) examined a bicameral chamber that mimics vivo conditions. Clusterin was almost exclusively apical unit apical:basal ratio 30:1. In contrast, had 1:1 1.5:1, respectively. Thus, for is different from testins. It noted FSH T, known regulators, did affect secretion . Due morphological intimacy between germ adluminal compartment testis, effects cell-conditioned investigated. Addition (1–30 μg protein) caused dose-dependent inhibition slight but statistically significant stimulation basal secretion. stimulated both apically basally. These observations suggest contains biological factor(s) differentially regulates bidirectional proteins. studies therefore reveal complicated regulatory processes involved epithelium.