Abstract
Humans and apes do not possess urate oxidase (UOX); hence, uric acid (UA) is the main end product of purine metabolism in these species. In other mammals with UOX, UA is further oxidized to allantoin (Alla) as the final product of purine metabolism. Based on these facts, we report a reliable method for identification of human urinary stains by the UA/urea nitrogen (UN) quotient, which is used as an indicator of the concentration of urinary components. From the results obtained, we have found that some New World monkeys excrete urine containing high levels of UA. Above all, urine from tufted capchin monkeys contained high levels of UA compared to those from humans and apes. In this paper, Alla and UA concentrations in plasma samples from humans, non-human primates, rats and guinea pigs were determined, and the Alla/UA quotients were compared among the mammals. The Alla/UA quotients for 16 humans and 6 apes were less than 0.1 and under 0.14, respectively. The Alla/UA quotients for 27 Old World monkeys were 0.7-2.0 while those of 5 prosimians, 5 rats and 5 guinea pigs were 1.2-3.0. For the New World monkeys, 5 common squirrel monkeys, 13 night monkeys, 9 cotton-headed tamarins and 8 common marmosets, the Alla/UA quotients were 0.9-1.8, 0.15-1.7, 0.2-1.3 and 0.2-1.0, respectively; some subjects in the latter three groups showed values similar to those in humans and apes. Alla/UA quotients from 11 tufted capuchin monkeys were 0.05-0.15, which was nearly the same as the quotient values of humans and apes. These results suggest that unlike humans and apes, tufted capuchin monkeys and some night monkeys, cotton-headed tamarins and common marmosets lack UOX activity in the liver.
