A COMPARISON OF THE RELATION BETWEEN THE RATE OF UREA EXCRETION AND THE AMOUNT OF RENAL TISSUE IN THE DOG AND OTHER MAMMALS

Abstract

[long dash]In 10 normal dogs adequate diuresis was provoked by fasting and administration of water and urea, the dog killed, the kidneys removed and the blood urea and urine urea estimated. The figures thus obtained were compared with those found by others for the rabbit and rat, and with figures indirectly obtained for man. In all 4 spp. the urine excretion ratio (urine urea rate:blood urea concentration) bore a direct relation to renal weight. In the dog the ratio value per gm. kidney wt. is a great deal higher than for any of the other 3 spp. examined, in all of which the relationship is essentially the same. It is suggested that the dog''s renal tubules may absorb less of the glomerular filtered urea than appears to be taken up by those of the frog, or that while man, rabbit and rat are omnivorous or herbivorous, the dog (at least in the material used) is enitrely carnivorous, and protein temporarily increases the urea ratio:kidney weight relation.