[Serum levels and urinary excretion of zinc in patients with insulin-dependent diabetes].
The objective of the work was to evaluate the basic parameters of zinc metabolism, i.e. serum levels and urinary excretion of zinc (Zn) in insulin dependent diabetes. The authors investigated a group of diabetics with normal renal function (DM) and with chronic renal insufficiency as a result of diabetic nephropathy (RIDM). Two control groups were formed by healthy volunteers (C) and non-diabetic subjects with chronic renal insufficiency (RI). In diabetics without impaired renal functions (DM) the Zn serum levels did not differ significantly from controls, urinary excretion was significantly raised. The authors did not reveal a correlation of serum Zn levels with parameters of compensation of diabetes nor with the insulin dose. Urinary Zn output correlated positively with proteinuria and the average blood sugar level during the collection of urine. The authors did not find a correlation with diuresis, fractional water excretion, glycosuria or urea excretion. The fractional Zn clearance in diabetic subjects was significantly raised and correlated with the mean blood sugar level. This finding suggests a decline of the tubular Zn absorption in hyperglycaemia. In diabetics with renal failure (RIDM) the results did not differ from non-diabetics with the same degree of renal insufficiency: serum Zn levels were, as compared with healthy controls, in both groups significantly reduced, the urinary excretion being normal. Thus insulin dependent diabetes nor its metabolic compensation do not influence in a marked way serum Zn levels but lead to higher urinary Zn losses.(ABSTRACT TRUNCATED AT 250 WORDS)