Metabolism of intravenous adenine in the pig.

1. Adenine administered either parenterally or orally is less toxic to the pig than to other species; doses of 100 mg/kg are rapidly catabolised and excreted largely as soluble purine end-products in the urine. 2. The low toxicity is explained by the excretion of less than 1% of the dose as 2,8-dihydroxyadenine. 3. These results suggest that adenine dosages which give rise to kidney damage must be above a threshold-like level which varies in the different mammalian species, and is higher in the pig than in the rat, dog, rabbit or man.