A 62-year-old womanwas initially hypothyroid and then developed hyperthyroidism with continuously positive thyroid-stimulating antibody (TSAb). Whenshe visited our hospital with the complaint of the feel of skipping beats, her serum free T4 level was initially low and thyrotropin (TSH) level was slightly elevated. One month after starting the supplement therapy with 1-T4, she developed hyperthyroidism with increased 123I-thyroid uptake. TSH-binding inhibitor immunoglobulin (TBII) was slightly elevated only during the hypothyroid stage. Throughout the whole course, TSAbwas continuously positive, while thyroid stimulation-blocking antibody (TSBAb) was not detectable. Primary hypothyroidism with TSAbmay suggest the possibility of subsequent development of hyperthyroidism. (Internal Medicine 34: 247-250, 1995)

Weinvestigated the relationship between the Trp64Arg mutation in the (33-adrenergic receptor gene and insulin sensitivity, which was evaluated by the euglycemic-hyperinsulinemicclamp technique, in 54 patients with impaired glucose tolerance (IGT) or non-insulin dependent diabetes mellitus (NIDDM)who were not receiving insulin therapy. The frequencies of Trp/Trp, Trp/Arg, and Arg/Arg genotypes in the patients were 63.0, 33.3, and 3.7%, respectively, which did not differ significantly from those of the 227 controls (67.0, 31.3, and 1.8 % , respectively). The mean glucose infusion rate of the 34 patients with Trp/Trp did not differ from that of the 18 patients with Trp/Arg (4.3 ± 2.2 and 5.3 ± 2.4 mg/kg/min, respectively); while that of the 2 patients with Arg/Arg was ll.5 mg/kg/min. There were no differences in the BMIor fat distribution in the abdomen between each genotype of patients, although the frequency of the Arg64 allele tended to increase with body mass index (BMI) in the control subjects under 60 years of age, which suggests that the mutation is involved in weight gain. (Internal Medicine 36: 603-606, 1997)