Serum IGF-1 levels correlate negatively to liver damage in diabetic rats

Ilkay Aksua, Basak Baykarab, Muge Kiraya, Tugba Gurpinarc, Ali Riza Sismand, Nuran Ekerbicere, Aysegul Tasa, Ozden Gokdemir-Yazara & Nazan Uysal*aa Dokuz Eylul University, Medical Faculty, Physiology, Izmir, Turkeyb Dokuz Eylul University, High School of Physical Therapy and Rehabilitation, Histology & Embryology, Izmir, Turkeyc Celal Bayar University, Medical Faculty, Pharmacology, Manisa, Turkeyd Dokuz Eylul University, Medical Faculty, Biochemistry, Izmir, Turkeye Celal Bayar University, Medical Faculty, Physiology, Manisa, TurkeyCorrespondence: Nazan Uysal, M.D., Professor of Physiology, Dokuz Eylul University Medical School, Department of Physiology, 35340 Balcova, Izmir, Turkey. Tel: 00-90-232-4124460, Fax: 00-90-232-4124459. E-mail: nazan.uysal@deu.edu.trAbstractDiabetes and insulin resistance frequently cause liver damage. Diabetes also causes reduction in liver and blood IGF-1 levels. We investigated the relation between liver damage and IGF-1 levels in diabetic rats. Fourteen Wistar albino rats were divided into control and diabetic groups. Diabetes was induced by streptozotocin. Rats were sacrificed for biochemical and histologic examinations 2 weeks after streptozotocin injection. Serum and liver IGF-1 levels were decreased, liver malondialdehyde (MDA) levels were increased, glutathione peroxidase (GPx) enzymes activities were decreased and serum alanine aminotransferase (ALT) levels were increased in diabetic group. Microscopic examination of liver revealed that normal tissue organization was disrupted in streptozotocin-induced diabetic rats. There was a strongly positive correlation between blood glucose levels and liver injury, and blood and liver IGF-1 levels. There was a strongly negative correlation between blood IGF-1 levels and hepatic injury. Our results suggest that reduction of blood IGF-1 levels correlates with hepatic injury and circulating IGF-1 levels may have predictive value for determining hepatic damage that results from diabetes. In addition, circulating IGF-1 levels are correlated with glutathione levels and the oxidative stress status of diabetic rat liver.