INFLUENCE OF SOME PHYSICO-CHEMICAL FACTORS ON BILIARY EXCRETION OF A SERIES OF STRUCTURALLY RELATED ARYL SULPHATE ESTERS

The metabolic fates and modes of excretion of biphenylyl 4-35S-sulphate, cyclohexylphenyl 4-35S-sulphate and cyclohexylphenyl 2-35S-sulphate were investigated in the rat. In experiments with free-ranging animals the bulk of the administered radioactivity was recovered in the urine. The proportion of urinary radioactivity appearing as inorganic 35S-sulphate was different for each ester (biphenylyl 4-35S-sulphate, 36 per cent in the male and 19 per cent in the female; cyclohexylphenyl 4-35S-sulphate, 33 per cent in the male and 19 per cent in the female; cyclohexylphenyl 2-35S-sulphate, less than 2 per cent in each sex). In experiments in which the esters were administered to rats with bile fistulae significant biliary elimination was recorded (biphenylyl 4-35S-sulphate, up to 18 per cent; cyclohexylphenyl 4-35S-sulphate, up to 81 per cent; cyclohexylphenyl 2-35S-sulphate, up to 70 per cent). In each case a single biliary metabolite was detected and this was identified as a glucuronic acid conjugate of the administered ester. Factors which might govern the respective levels of biliary excretion are discussed. © 1969.