Abstract
Twenty-five patients with hyperthyroidism were classified into the three groups; normal (8), borderline (10) and diabetic ones according to the diagnostic criteria for diabetes, proposed by the Japan Diabetic Association. Blood glucose, FFA and IRI levels before and after the oral administration of 50 g of glucose in each of the thyrotoxic groups were compared with those obtained from 10 control subjects. The results were as follows.
1. In the thyrotoxic patients the blood glucose levels were significantly higher than those in the control group at 30, 60, 120 minutes after glucose loading. Even in the group of hyperthyroidism with normal glucose tolerance, the level of blood glucose was significantly increased at 30 minutes. Nine cases of 10 borderline subjects showed oxyhyperglycemia in the glucose tolerance test.
2. The plasma levels of IRI in hyperthyroidism were significantly elevated before and at 120, and 180 minutes after glucose loading. There was a tendency indicating that to some extent the severer the impairment of glucose tolerance, the higher the plasma IRI response to glucose loading. In patients with much more severe impairment in glucose tolerance, the response of plasma IRI to the glucose showed slightly lower and delayed pattern.
3. The fasting levels of FFA in hyperthyroidism were higher than those of control group and promptly decreased with a subsequent reboud at 180 minutes in response to glucose loading. In thyrotoxic patients showing diabetic glucose tolerance curve, serum FFA tended to fall more slowly and never returned to its initial level at 180 minutes.
Possible mechanism of glucose intolerance in hyperthyroidism was discussed.
