Tohoku J. Exp. Med., 2003, 199 (2)

Hyperuricemia in Hypothyroidism: Is It Associated with Post-Insulin Infusion Glycemic Response ?

NURAN DARIYERLI, GÜLNUR ANDICAN,1 ALP BURAK ÇATAKOGLU,2 HÜSREV HATEMI3 and GÜLDEN BURçAK1

Department of Physiology, 1Department of Biochemistry, Cerrahpaa Medical Faculty, Istanbul University, 2Department of Cardiology, Florance Nightingale Hospital, Kadir Has University, 3Department of Internal Medicine, Cerrahpaa Medical Faculty, Istanbul University, Istanbul, Turkey

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.

Keywords —— hypothyroidism; hyperuricemia; post insulin infusion glycemic response; triglycerides; magnesium

© 2003 Tohoku University Medical Press

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Tohoku J. Exp. Med., 2003, 199, 59-68

Address for reprints: Nuran Dariyerli, Department of Physiology, Cerrahpasa Medical Faculty, Istanbul University, Bosna bulvari Ata 2 Sitesi, Erguvan cad. 79/7 Çengelköy, Uskudar, Istanbul, Turkey.

e-mail: dariyerli@yahoo.com