Effects of ten steroids on acridine orange uptake and β-N-acetylglucosaminidase levels in rat liver lysosomes

Abstract

Ten steroids have been compared for their ability to modify the rate of uptake of acridine orange by rat liver and by rat liver lysosomes in vivo . The short-term effects of the ten steroids on the specific activity of a lysosomal enzyme, β-N-acetylglucosaminidase, were also compared. Five of the ten steroids were administered as tritium-labelled compounds and the concentration of steroids or metabolites was measured in rat liver and liver lysosomes at 2.5 h and 3.75 h after administration. Cortisone acetate, etiocholanolone (5β-androstan-3α-ol-17-one) and testosterone accelerate and increase the uptake of acridine orange by rat liver lysosomes. Deoxycorticosterone, corticosterone, triamcinolone (9α -fluoro-11β, 16α, 17, 21-tetrahydroxy-pregna-1, 4-diene-3, 20-dione), estra-diol-17β and progesterone appear to inhibit the uptake of acridine orange by rat liver lysosomes at 2.5 hours. Cortisol and dexamethasone (9α-fluoro-11β, 17, 21-trihydroxy-16α-methyl-pregna-1, 4-diene-3, 20-dione) had little effect. All steroids with the exception of etiocholanolone and deoxycorticosterone increase the specific activity of β-N-acetylglu-cosaminidase in the lysosomal fraction at 2.5 h. Nope of the effects at 2.5 h are due to lowered protein levels. Lysosomal concentrations of radioactivity following the administration of tritiated steroids were greatest for the glucocorticoids, corticosterone and cortisol. Estradiol-17β progesterone and testosterone showed much lower concentrations of radioactivity in isolated lysosomes. Most of the lysosomal radioactivity (73–96%) was associated with the soluble fraction of the disrupted lysosomes.