Effect of carbohydrate intake on serum 3,5,3'-triiodothyronine-response to glucose ingestion and its relation to glucose tolerance in lean non-insulin-dependent diabetic patients.

This study was conducted to know the effect of carbohydrate intake on serum 3,5,3'-triiodothyronine (CAS 6893-02-3, T3)-response to glucose ingestion and its relation to glucose tolerance in lean non-insulin-dependent diabetes mellitus (NIDDM) patients. Ten patients, body mass index: 21.8 +/- 2.2 (mean +/- SD) kg/m2, were given a control diet (2012 kcal/day(d); carbohydrate (CHO): 299 g/d) on admission. Several days later, they were given a low-calorie and low-CHO diet (Low-CHO) (1156 kcal/d; CHO: 139 g/d) and 2 weeks later, they received a low-calorie and high-CHO diet (High-CHO) (1154 kcal/d; CHO: 176 g/d) and another 2 weeks later, they were given Low-CHO again for 2 weeks. They received oral 75 g glucose tolerance tests after completion of each diet. sigma dGlucose (mmol/l) decreased from 54.3 +/- 11.9 (control) to 42.5 +/- 7.5 after Low-CHO and reached 34.5 +/- 10.4 after High-CHO but increased to 36.4 +/- 11.1 after the 2nd Low-CHO (F = 7.46, p = 0.0005). sigma dT3 (nmol/l) increased from -0.18 +/- 0.52 (control) to 0.12 +/- 0.67 after Low-CHO and reached 0.92 +/- 0.59 after High-CHO but decreased to 0.36 +/- 0.65 after the 2nd Low-CHO (F = 5.92, p = 0.0022). Serum insulin and body weight remained unchanged throughout the study. Negative correlation between sigma dT3 and sigma dGlucose (r = -0.493, n = 40, p = 0.0012) was found throughout the diet modification. Carbohydrate intake affected serum T3-response to glucose ingestion and the response was closely related to glucose tolerance in lean NIDDM patients.