Zinc levels after intravenous administration of zinc sulphate in insulin-dependent diabetes mellitus patients.

Diabetic patients commonly have increased urinary excretion of zinc, although blood concentrations may be normal, lowered, or raised. We analyzed zinc levels in plasma and urine after an intravenous overload of zinc sulphate (8 mg) in 22 patients with insulin-dependent diabetes mellitus (IDDM) and 22 healthy individuals. No significant differences were found in basal levels of serum zinc in either group (111 +/- 29 micrograms/dl in IDDM vs 119 +/- 19 micrograms/dl in controls), although urinary excretion of zinc was significantly raised in diabetics (1396 +/- 622 micrograms/24 h) versus controls (611 +/- 235 micrograms/24 h). After zinc overload, both serum and urinary levels of this element varied between the two groups. Serum zinc in IDDM patients initially increased more markedly, and subsequently showed a more significant decline, than in controls. Urinary zinc levels in IDDM patients, in contrast to control values, showed no increase after overload. These alterations in serum and urinary zinc concentrations suggest that our diabetic patients may be zinc-deficient.