Table of Contents
ISRN Endocrinology
Volume 2013 (2013), Article ID 148497, 9 pages
http://dx.doi.org/10.1155/2013/148497
Clinical Study

Improved Insulin Sensitivity during Pioglitazone Treatment Is Associated with Changes in IGF-I and Cortisol Secretion in Type 2 Diabetes and Impaired Glucose Tolerance

Department of Molecular Medicine and Surgery, D2:04, Karolinska Institutet and Karolinska University Hospital, 17176 Stockholm, Sweden

Received 27 November 2012; Accepted 19 December 2012

Academic Editors: C. Anderwald, F. Escobar-Jimenez, T. W. Furlanetto, P. Morosini, and H. Tamemoto

Copyright © 2013 Lisa Arnetz et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Background. Hypercortisolism and type 2 diabetes (T2D) share clinical characteristics. We examined pioglitazone's effects on the GH-IGF-I and HPA axes in men with varying glucose intolerance. Methods. 10 men with T2D and 10 with IGT received pioglitazone 30–45 mg for 12 weeks. OGTT with microdialysis in subcutaneous adipose tissue and 1 μg ACTH-stimulation test were performed before and after. Glucose, insulin, IGF-I, IGFBP1, and interstitial measurements were analyzed during the OGTT. Insulin sensitivity was estimated using HOMA-IR. Results. HOMA-IR improved in both groups. IGF-I was initially lower in T2D subjects ( ) and increased during treatment ( to SD; ); no change was seen in IGT ( SD before and during treatment). Fasting glycerol decreased in T2D ( ), indicating reduced lipolysis. Fasting cortisol decreased in T2D ( to  nmol/L; ) but increased in IGT ( to  nmol/L; ). Peak cortisol was lower in T2D during treatment ( to , versus to  nmol/L in IGT; ). Conclusions. Pioglitazone improved adipose tissue and liver insulin sensitivity in both groups. This may explain increased IGF-I in T2D. Pioglitazone affected cortisol levels in both groups but differently, suggesting different mechanisms for improving insulin sensitivity between T2D and IGT.