The oxidation of dimethylthetin and related compounds to sulphate in the rat

Abstract

Sulphonium salts, such as the trimethylsulphonium and triethylsulphonium halides, possess certain of the pharmacological properties of quater- nary ammonium compounds (Crum Brown & Fraser, 1872) and have been given some attention on this account in the past More recently, interest in sulphonium compounds has centred on the thetins and their role in transmethylation. Du Vigneaud (1942-3) first reported that dimethylthetin chloride (carboxymethyldimethylsulphonium chloride) {(CH3)2S'CH2CO2H}Cl, could sup- port the growth of rats fed on a methyl-deficient diet supplemented with homocystine, and that it could act, like choline and glycine betaine, as a methyl donor in the rat (Du Vigneaud, Moyer & Chandler, 1948). A related thetin, dimethyl-f,propiothetin, was also found to be an active methyl donor (Maw & Du Vigneaud, 1948a); this is of significance in view of its natural occurrence in a marine alga (Challenger & Simpson, 1947, 1948). Ethylmethylthetin is partly active in this respect, whereas diethylthetin, lacking the necessary methyl groups, is inactive (Maw & Du Vigneaud, 1948c). Dubnoff & Borsook (1948a), using rat, pig and guinea-pig liver suspensions, demonstrated the