Renal clearance and excretion of endogenous substances in the owl monkey

The clearance and excretion of creatinine, calcium, phosphorus, sodium, and potassium by the kidney was evaluated in 62 owl monkeys using timed urine collections and quantitative urinalyses. The endogenous clearance of creatinine was determined for each monkey. Urinary electrolyte excretion and fractional electrolyte excretions (FE) were measured. Linear regression analysis was used to calculate the correlation between urinary excretion and FE for each electrolyte. The coefficient of determination for each analyte was significant (P ? .0001). Determination of FE was found to be an appropriate indicator of the renal handling of electrolytes and, when viewed in conjunction with urinalysis and other serum parameters, an aid in evaluating renal function in the owl monkey. © 1992 Wiley-Liss, Inc.