Dariyerli Nuran, Andican Gülnur, Catakoğlu Alp Burak, Hatemi Hüsrev, Burçak Gülden
Department of Physiology, Cerrahpaşa Medical Faculty, Istanbul University, Istanbul, Turkey.
Tohoku J Exp Med. 2003 Feb;199(2):59-68. doi: 10.1620/tjem.199.59.
This experimental study was designed to examine whether hyperuricemia in hypothyroidism is associated with insulin resistance. For induction of hypothyroidism, rabbits (n = 12) were administered methimazole orally (75 mg/100 g food) for 30 days. T3, T4 and TSH values measured in plasma prior to and at the end of the experimentation period revealed the establishment of hypothyroidism. In the euthyroid and hypothyroid states of rabbits, crystalline porcine insulin was administered (0.1 unit/kg body weight) intraperitoneally and plasma glucose was measured at 0, 15, 30, 45 and 60 minutes. Sum of post insulin infusion glucose values was considered to reflect insulin resistance. Creatinine clearance (GFR) and uric acid clearance (CuA) were determined. Additionally, triglycerides were measured in plasma and Mg2+ both in erythrocytes and in plasma. Due to hypothyroidism: i) The glycemic response to insulin was not altered. ii) GFR and CuA were both decreased but CuA/GFR unchanged. iii) Triglycerides in plasma decreased. iv) Mg2+ concentration increased in plasma whereas decreased in erythrocytes. Several associations were observed between the variables on correlation analysis. On the basis of our data, it could be suggested that insulin resistance does not exist in hypothyroidism. Hyperuricemia observed in hypothyroidism should be considered to be secondary to decreased renal excretion but not as an indicator of insulin resistance.
本实验研究旨在探讨甲状腺功能减退症中的高尿酸血症是否与胰岛素抵抗有关。为诱导甲状腺功能减退症，给12只兔子口服甲巯咪唑（75毫克/100克食物），持续30天。在实验期开始前及结束时测量血浆中的T3、T4和TSH值，结果显示已成功诱导出甲状腺功能减退症。在兔子的甲状腺功能正常和减退状态下，腹腔注射结晶猪胰岛素（0.1单位/千克体重），并在0、15、30、45和60分钟时测量血浆葡萄糖。胰岛素输注后葡萄糖值的总和被视为反映胰岛素抵抗。测定肌酐清除率（GFR）和尿酸清除率（CuA）。此外，还测量了血浆中的甘油三酯以及红细胞和血浆中的Mg2+。由于甲状腺功能减退症：i）对胰岛素的血糖反应未改变。ii）GFR和CuA均降低，但CuA/GFR不变。iii）血浆中的甘油三酯降低。iv）血浆中Mg2+浓度升高，而红细胞中Mg2+浓度降低。相关性分析观察到变量之间存在几种关联。根据我们的数据，可以认为甲状腺功能减退症中不存在胰岛素抵抗。甲状腺功能减退症中观察到的高尿酸血症应被视为继发于肾脏排泄减少，而不是胰岛素抵抗的指标。
