J Korean Soc Endocrinol.  1994 Jun;9(2):108-114.

Changes in Insulin Sensitivity and Insulin Secretory Function in Hyperthyroid Patients

• Lee DH
• Chung MY
• Jang YJ
• Park SS
• Choi EJ
• Kang HC
• Cho JH
• Lee TH

Abstract

The impairement of glucose metabolism is frequently associated in hyperthyroidism. The present study was performed to determine the effect of the thyroid hormone excess on insulin sensitivity and on insulin secretory function in vivo. Ten newly diagnosed hyperthyroid patients and fifteen healthy control subjects were subjected to frequently sampled intravenous glucose tolerance tests(FSIGT) after an overnight fast. Insulin sensitivity, represented by the insulin sensitivity index(S_1), was assessed by minimal model analysis of FSIGT data. Insulin secretion was measured by the total area under the insulin curve after glucose load.The results were as follows.1) The K_G values, which represent glucose tolerance, were not different between the hyperthyroid patients and the normals(2.2+-0.3 vs. 2.5+-0.3%/min, p>0.05).2) S_1 was significantly decreased in the hyperthyroid patients in comparison to the normals(7.5+-1.4 vs. 2.6+-0.3X10^-4 min^-1/uU/ml, p<0.05).3) The basal insulin concentration was higher in the hyperthyroid patients than in the normals(8.3+-2.4 vs. 4.6+-0.4 uU/ml, p=0.07). In addition, the insulin secretory response to a glucose load was increased in the hyperthyroid patients as evidenced by the peak plasma insulin level(168.2+-30.4 vs. 89.2+-13.9 uU/ml, p<0.05) and by the total area under the insulin curve(2641.1+-443.2 vs. 1696.7+-204.3 min uU/ml, p<0.05).These results clearly demonstrated that insulin sensitivity was impaired in these newly diagnosed hyperthyroid patients. However, glucose tolerance was maintained by the increased insulin secretion.

MeSH Terms

Glucose
Glucose Tolerance Test
Humans
Hyperthyroidism
Insulin Resistance*
Insulin*
Metabolism
Plasma
Thyroid Gland
Glucose
Insulin