[Changes in circulating lymphocyte triiodothyronine receptors in diabetes mellitus]

Using radioligand binding assay of receptors, we studied the changes of T3 receptors in circulating lymphocytes in 20 normal persons and 43 diabetic patients with or without low T3. The mean value of serum T3 and FT3 was significantly decreased in all diabetic patients compared with that of normal controls. The concentration of serum T3 was negatively correlated with fasting blood glucose level. The serum rT3 was clearly increased in patients with low T3. The serum T4, FT4, FT4 I and TSH were normal in all patients The maximal binding capacity (MBC) of circulating lymphocyte T3 receptors which was negatively correlated with the serum T3 concentrations was obviously elevated in patients with diabetes mellitus. It was still higher in patients with low T3 than in patients with normal T3, whereas the affinity of receptor was not changed. In conclusion, the increment of T3 receptor binding capacity reflects the compensatory mechanisms, which are probably evoked by the T3 deficiency in order to maintain cellular homeostasis.