The metabolism of potassium dodecyl [35S]-sulphate in the rat

Abstract

The metabolic fate of potassium dodecyl [35S]sulphate was studied in rats. Intraperitoneal and oral administration of the ester into free-ranging animals were followed by the excretion of the bulk of the radioactivity in the urine within 12hr., approximately 17% being eliminated as inorganic [35S]sulphate. Similar results were obtained in experiments in which potassium dodecyl [35S]sulphate was injected intravenously into anaesthetized rats with bile-duct and ureter cannulae. Analysis of urinary radioactivity revealed the presence of a new ester sulphate (metabolite A). This metabolite was isolated, purified and subsequently identified as the sulphate ester of 4-hydroxybutyric acid by paper, thin-layer and gas chromatography, by paper electrophoresis and by comparison of its properties with those of authentic butyric acid 4-sulphate. The identity of the metabolite was confirmed by isotope-dilution experiments. When either purified metabolite A or authentic potassium butyric acid 4[35S]-sulphate was administered to free-ranging rats the bulk of the radioactivity was eliminated unchanged in the urine within 12hr., approx. 20% of the dose appearing as inorganic [35S]sulphate. Whole-body radioautography and isolated-liver-perfusion experiments implicated the liver as the major site of metabolism of potassium dodecyl [35S]sulphate. It is suggested that butyric acid 4-sulphate probably arises by ω-oxidation of dodecyl sulphate to a fatty acid-like compound, which is then degraded by β-oxidation.