[Hormonal aspects of cathepsin D regulation in seminal follicles]

Androgen-dependent regulation of cathepsin D activity was studied in rat seminal follicles. Cathepsin D, isolated from the follicles by means of ammonium sulfate fractionation, chromatography on Hb-Sepharose and Sephadex G-200, was similar to the enzyme from other tissues in molecular mass, Km for hemoglobin, pH optimum of activity, thermolability. Concentration of androgens in tissues affected the properties of purified cathepsin D: the enzyme activity, its sensitivity to thermoinactivation and to chymotryptic hydrolysis were increased as well as the pH optimum was expanded after orchidectomy. Testosterone restored the initial enzyme properties altered after castration.