Changes in zinc metabolism during the course of the nephrotic syndrome.

The plasma zinc concentration and quantitative urinary zinc excretion were studied in 105 pediatric patients with the nephrotic syndrome or nephritis-nephrosis. The plasma level was decreased to a mean value of 51.7 microgram/dL in patients with the nephrotic syndrome (controls, 85 microgram/dL). The rate of urinary zinc excretion was not different from that of the controls, with the exception of patients whose disease was in the polyuric phase of beginning remission where it was fivefold higher and those who had achieved a long-lasting remission of the disease. Since about two thirds of the plasma zinc is bound to albumin, an unchanged zinc-albumin ratio would reflect an equal zinc and albumin loss. The ratio, however, was increased twofold and thus does not adequately explain the hypozincemia. The low hair level of 86 microgram/g may suggest a more profoundly disturbed zinc metabolism than originally thought.