A longitudinal study of the kidney function of the chimpanzee (Pan troglodytes) in comparison with humans

A prospective study of the kidney function of chimpanzees (Pan troglodytes) kept at the Hans Popper Primate Centre has been performed within the last 10 years. The aim of the study was to analyse urine samples for specific gravity, to determine serum creatinine, serum urea, and urinary creatinine, and to calculate creatinine clearance and reference values for healthy chimpanzees. From 1750 urine specimens of adolescent and 568 of infant chimpanzees a mean specific gravity value of 1.013 +/- 0.006 (standard deviation) kg/l and 1.007 +/- 0.003 (standard deviation) kg/l, respectively, was calculated. Serum creatinine was determined in 1864 single samples from 52 chimpanzees; a median value of 101.8 mumol/l (P (5%) 79.6 mumol/l, P (95%) 139.7 mumol/l) was calculated, which is higher than that in humans. Serum urea tests (n = 1831) in the same 52 chimpanzees resulted in a median value of 2.01 mmol/l (P (5%) 0.86 mmol/l, P (95%) 4.78 mmol/l). The calculated median creatinine clearance value of 23.9 ml/min (P (5%) 4.4 ml/min, P (95%) 65.3 ml/min) is lower in chimpanzees than in man. A correction of the creatinine clearance values to the body surface area of 1.73 m2, as routinely performed in humans, gave unusually high results, as there was no proper equation to calculate the surface area of chimpanzees. The use of estimation equations for creatinine clearance values of chimpanzees as developed for humans is therefore not recommended.