The metabolism in vivo of 3 alpha, 5 beta-tetrahydroaldosterone in the guinea pig.

Analysis of urinary metabolites of [1, 2-3H]-3 alpha, 5 beta-tetrahydroaldosterone was performed in male guinea-pigs. Separation of urinary metabolites was carried out by means of DEAE-Sephadex A-25 column chromatography and four fractions (fraction A to fraction D) were detected. 46-50% of fraction A was extractable with ethyl acetate. When ethyl acetate extract was submitted to reversed phase high pressure liquid chromatography, a number of peaks were present and one of these peaks cochromatographed with 3 alpha, 5 beta-tetrahydroaldosterone. Fraction B, fraction C and fraction D were incubated with enzyme and the free steroid released was identified on the basis of retention time on reversed phase high pressure liquid chromatography. Thus, fraction B contained monoglucosiduronate of 3 alpha, 5 beta-tetrahydroaldosterone, whereas identification of fraction C was not successful. Fraction D was characterized as a monosulphate; 3 beta, 5 beta-tetrahydroaldosterone, 3 alpha, 5 beta-tetrahydroaldosterone and 3 beta, 5 alpha-tetrahydroaldosterone were identified as aglycones. It is probable that 3 beta, 5 alpha-tetrahydroaldosterone is converted from other tetrahydroisomers by intestinal bacteria of the guinea-pig, since mammalian tissues do not contain enzymes that introduce a double bond into ring A.