ZINC-METABOLISM IN NON-INSULIN-DEPENDENT DIABETES-MELLITUS

Low plasma zinc concentrations and increased zinc excretion have been reported in patients with non-insulin dependent diabetes mellitus (NID DM), This study was designed to compare zinc metabolism in ten NIDDM p atients with ten healthy controls, using stable isotopes of zinc. Zinc absorption from a standard breakfast labelled extrinsically with 3mg Zn-67 was measured using a faecal monitoring technique and thermal ion ization quadrupole mass spectrometry. One hour after the test meal eac h volunteer was given 0.5 mg Zn-70 (as citrate) intravenously and bloo d samples taken at intervals for up to 6 days. Isotopic enrichment was measured and the data entered into a simple kinetic model to estimate the size and rate of turnover of exchangeable pools of zinc. Urinary zinc excretion was higher in the male diabetics than controls (p<0.05) , but not in females. Since the efficiency of absorption and endogenou s losses of zinc were very variable between individuals, and there was only a limited amount of data, it was not possible to draw conclusion sn about the effect of NIDDM on zinc absorption and excretion. However , the fact that there were no differences in exchangeable zinc pool si zes suggests that zinc metabolism is not altered in NIDDM.