THE EXCRETION OF INULIN AND CREATININE BY THE ANTHROPOID APES AND OTHER INFRAHUMAN PRIMATES

Abstract

The simultaneous clearances of exogenous creatinine and inulin was examined in the orang-utan, gibbon and chimpanzee, 2 spp. of baboon and in the macaque monkey. The creatinine/inulin clearance ratio in a limited series of observations averaged 1.48 in the orang-utan, 1.23 in the gibbon and 1.22 in the chimpanzee. In the chimpanzee elevation of the plasma level of creatinine depresses the creatinine/inulin clearance ratio towards unity, indicating that the difference between these clearances is due to the tubular excretion of creatinine. Phlorizin abolishes this tubular excretion and blocks the tubular reabsorption of glucose. In the baboon and macaque the creatinine clearance appears to be slightly greater than the inulin clearance, but elevation of the plasma creatinine level in one expt. in the macaque did not depress this ratio. If tubular excretion of creatinine occurs in these animals it is of such a small order of magnitude that the creatinine clearance exceeds the inulin clearance by an amt. only slightly larger than the exptl. error in the detn. of these clearances.