Renal clearance, tubular reabsorption and urinary excretion of albumin in monkeys infected with Plasmodium knowlesi.

The glomerular filtration rate (GFR) and the glomerular clearance rate of albumin were determined in 6 rhesus monkeys infected with P. knowlesi as well as in 6 control monkeys by using 51Cr-EDTA and 125I-HSA respectively. The excreted albumin in the urine was also determined and used for calculating the renal clearance value. The amount and rate of albumin filtered in the glomeruli and reabsorbed by the tubules were then calculated from these parameters. The present study showed that the rate and amount of albumin filtered through the glomeruli, reabsorbed by tubules and excreted in the urine of normal monkeys, which were similar to results reported earlier in normal human, dogs and rats. In the monkeys infected with P. knowlesi the glomerular filtration rate was reduced while the glomerular clearance rate of albumin increased which resulted in the significantly elevated filtered albumin in the glomeruli. The tubular reabsorptive capacity to plasma albumin was also found to be significantly increased in parallel to the elevated filtered load of albumin. However, as this capacity was limited, the excess albumin was therefore excreted into the urine in the infected monkeys. All these findings indicated that the albuminuria in P. knowlesi-infected monkeys was due to the increased glomerular capillary permeability to plasma albumin, although the tubular reabsorptive capacity increased but could not cope with a very high filtered load, therefore, excess albumin was detected in the urine.