Studies on serum ketone bodies in patients with hyperthyroidism

In order to investigate effects of thyroid hormone on ketone bodies metabolism, fasting levels of serum ketone bodies, serum free fatty acids (FFA), serum insulin (IRI), plasma glucagon (IRG) and plasma glucose were examined in 29 untreated patients with hyperthyroidism and 20 healthy subjects. In 21 patients the levels of serum ketone bodies were re-examined when euthyroidism was achieved after treatment. In all of healthy subjects and 17 patients changes in the levels of serum ketone bodies after oral glucose load were examined. The results were as follows: 1). Fasting levels of serum FFA and total ketone bodies (TK), acetoacetate (AcAc), 3-hydroxy-beta-butylate (3OHBA), ratio of 3OHBA to AcAc in the patients were significantly higher than those in healthy subjects. The levels of IRI, IRG or ratio of IRG to IRI in the patients were not different from those in healthy subjects. In the patients, the fasting level of TK was significantly correlated with the level of FFA. 2). After oral glucose load the levels of TK and FFA in the patients decreased gradually. 3). The fasting levels of TK and FFA in the patients decreased when euthyroidism was achieved after treatment. It was suggested that the fasting levels of serum ketone bodies in patients with hyperthyroidism elevated probably due to activated lipolysis.