The excretion of urea, ammonia and purine end-products by the newborn animal

Abstract

The excretion of urea, ammonia, uric acid and allantoin by newborn babies, pigs and puppies was studied, and the results were compared with those for adults of the same species. The percentage of the total N excreted as urea was lower in the newborn than in the adult of the same species. This was attributed to the direction of the turnover of amino acids toward anabolism at this age. The new-born baby, pig and puppy excreted a higher proportion of their N as ammonia than did the adults. The reasons for this are discussed. New-born pigs and puppies excreted more of their purine end-products as uric acid than did corresponding adults. In the urine formed by puppies in the uterus allantoin contributed a higher percentage of the total N than did urea. The percentage contributed by allantoin declined rapidly after birth.