The Effect of Administration of Small Doses of Thyroxine on Glucose and Lipid Metabolism, in Type 2 Diabetes Mellitus.
Condition: Diabetes Mellitus
MeSH terms: Diabetes Mellitus; Diabetes Mellitus, Type 2
Study type: Interventional

Summary: 
      We investigated the effect of the administration of small doses of thyroxine to healthy
      humans and patients with type 2 diabetes on postprandial forearm muscle glucose uptake,
      insulin sensitivity indices, lipid metabolism, in vitro glucose uptake and GLUT4 recruitment
      in the plasma membrane of monocytes.
    

Detailed description: 
      The present open-labeled, randomized and placebo-controlled study was undertaken in euthyroid
      type 2 diabetic patients and healthy humans, to examine the effect of administration of small
      doses of thyroxine within the euthyroid range, on muscle glucose disposal, postprandial
      insulin sensitivity, lipid metabolism, in vitro glucose uptake and GLUT4 recruitment in the
      plasma membrane of monocytes.This was investigated with the arteriovenous-difference
      technique after the consumption of a mixed meal and the in vitro study of a glucose
      analogue(6-NBDG) uptake by the peripheral monocytes.

      Subjects and Methods: Eleven euthyroid, treatment naive, type-2 diabetic patients with a
      micronodular texture of the thyroid gland and eleven healthy euthyroid subjects, were studied
      before and after administration of 50 μg of thyroxine once daily for 2 months. In parallel, a
      placebo group was also studied. Eleven euthyroid treatment-naïve subjects with type 2
      diabetes and a micronodular texture of the thyroid gland, matched for age, sex, BMI, and
      basal thyroid function, were studied before and after administration of a placebo, once daily
      for 2 months.

      Experimental protocol: All subjects were admitted to the hospital at 0700 h after an
      overnight fast and had the radial artery (A) and a forearm deep vein (V) catheterized. A meal
      (730kcal, 50%carbohydrate, of which 38% was starch, 40% fat, and 10% protein) was given at
      least 1 h after catheter insertion and was consumed within 20 min. Blood samples were drawn
      from both sites before the meal (at -30 and 0 min) and at 30- to 60-min intervals for 300 min
      thereafter for measurements of thyroid hormones,glucose, total cholesterol, LDL Cholesterol,
      HDL Cholesterol, triglycerides, Apolipoprotein A1, Apolipoprotein BII and Lp(a).Forearm blood
      flow was measured with strain-gauge plethysmography. After the first meal tolerance test,
      treatment with 50μg of thyroxine or placebo, once daily, was initiated for a 2-month period.
      Then a second identical test was repeated. Special care was taken in order to avoid the
      induction of subclinical hyperthyroidism, that is suppression of TSH below 0.27 μU/ml, as it
      has recently been shown that the latter is also an insulin-resistant condition.
    

Intervention name(s): thyroxine; Placebo; A meal (730kcal, 50%carbohydrate, of which 38% was starch, 40% fat, and 10% protein)
Intervention type(s): Drug; Drug; Other
Intervention description(s): treatment with 50μg of thyroxine once daily for two months.; treatment with 50μg of placebo, once daily, for two months.
Other intervention name(s): T4
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: Diabetes mellitus, thyroxine