[Investigation on the relationships among blood zinc, copper, insulin and thyroid hormones in non-insulin dependent diabetes mellitus and obesity]

Abstract

Zinc is known to have important effects on insulin activity, to increase the body fat deposition, and thyroid hormones conversion (T4 to T3). It is also known to have intestinal absorption competition between zinc and copper. This study was to investigate the blood zinc and copper concentrations in NIDDM and obesity, the relationships among metals, insulin, and thyroid hormones were also determined. Blood samples of diabetic, obese, and healthy individuals were collected between 9-10 AM, and the blood levels of zinc, copper, insulin, T4 and T3 were assayed. The results showed that diabetics and obese individuals had higher insulin and T3 levels than healthy controls, but there was no difference in T4. The obese had lower serum zinc concentration. There were low levels of copper both in serum and erythrocyte, and a low erythrocyte zinc concentration in NIDDM. Blood zinc concentration was inversely related to T3 level in diabetics and obese individuals. It is suggested that zinc, insulin and T3 may have considerable correlations in the thermoregulation on NIDDM and obesity, and the true mechanisms still need more further studies in the future.