Comparative Studies in the Sulfur Metabolism of the Dog and Pig

Hele (1) has found that in the dog, maintained on a low protein diet, ethereal sulfates may be formed at the expense of endogenous sulfates.He has further shown, in support of Baumann's theory (2), that in the dog, the endogenous sulfates which are utilized in the synthesis of ethereal sulfates can be in part replaced by dietary inorganic sulfates.White and Lewis (3) obtained similar results with p-bromophenol.In contrast to the dog, the pig does not seem readily to yield ethereal sulfates in the urine from the administered phenol, iodophenol, or chlorophenol.Supplementing the diet of the pig with kcystine or NazSO., does not augment the synthesis of ethereal sulfates (4, 5).Furthermore, no p-bromophenylmercapturic acid could be either isolated (presumably by Baumann-Schmitz's method ( 6)) or detected by studying the sulfur partitions of the urine of pigs which were fed bromobenzene (5).Accordingly, Coombs and Hele (5) postulated that the pig, in contrast to the dog, does not utilize exogenous sulfur readily for detoxication purposes in general and does not, apparently, synthesize mercapturic acids in particular.Recent studies have shown that isobarbituric acid readily yields ethereal sulfates in the urine of adult (7) and growing dogs (S), humans (9), and rabbits (10).Experiments were undertaken with the object of ascertaining the metabolism of isobarbituric acid in the pig.It also seemed of interest to see whether or not the synthesis of isobarbituric acid sulfate in dogs and pigs conforms to the theory of Baumann (2).