Effect of Antiliyolytic Agents on Glueose Metabolism in Thyrotoxic Patients / 대한내분비학회지

ABSTRACT

Decreased glucose tolerance is often found in patients with thyrotoxicosis but the pathogenetic mechanisms are poorly understood. Since the concentrations of free fatty acid are usually elevated due to increased lipolysis in thyrotoxicosis, the preferential oxidation of the free fatty acids may explain the decreased glucose tolerance in hyperthyroidism. The aim of this study was to investigate whether lowering plasma free fatty acid(FFA) by acipimox, a long-acting antilipolytic agent, could affect glucose metabolism in thyrotoxicosis. We performed intravenous glucose tolerance test with acipimox or placebo in 6 untreated thyrotoxicmen and 6 age-and body mass index(BMI)-matched controls. The following results were obtained.1) The basal plasma FFA concentration in thyrotoxic patients were significantly higher than those in controls(997.0+-303.4 uEq/L vs. 290.5+-169.1 uEq/L; p<0.01). 2) Plasma FFA concentrations decreased rapidly with acipimox ingestion in both controls and thyrotoxic patients.3) Plasma glucose concentrations were significantly lower with acipimox ingestion than with placebo in thyrotoxic patients from 17min after intravenous glucose load and to the end of the study.4) Plasma insulin concentrations in thyrotoxic patients with acipimox ingestion were higher at 5, 7 min after iv glucose load.5) In thyrotoxic patients, glucose disappearance rate(K_glucose) in acipimox treatment was significantly higher than that in placebo treatment(2.44+-0.84 vs. 1.58+-0.37;p<0.05). 6) K_glucose values were inversely correlated with basal FFA concentrations(r=-0.58, p<0.05). In summary, in thyrotoxic patients with elevated plasma FFA levels, acipimox lowered plasma FFA, which in turn improved glucose tolerance.