Relationship of Liver Enzymes to Insulin Sensitivity and Intra-Abdominal Fat
Tara M. Wallace , MD 1 ,
Kristina M. Utzschneider , MD 1 ,
Jenny Tong , MD 1 ,
Darcy B. Carr , MD 2 ,
Sakeneh Zraika , PHD 1 ,
Daniel D. Bankson , MD 3 ,
Robert H. Knopp , MD 4 and
Steven E. Kahn , MB, CHB 1
1 Department of Medicine, VA Puget Sound Health Care System, and University of Washington, Seattle, Washington
2 Department of Obstetrics and Gynecology, University of Washington, Seattle, Washington
3 Department of Pathology and Laboratory Medicine, VA Puget Sound Health Care System, and University of Washington, Seattle,
Washington
4 Harborview Medical Center, University of Washington, Seattle, Washington
Address correspondence and reprint requests to Steven E. Kahn, MB, ChB, VA Puget Sound Health Care System (151), 1660 S. Columbian
Way, Seattle, WA 98108. E-mail: skahn{at}u.washington.edu
Abstract
OBJECTIVE — The purpose of this study was to determine the relationship between plasma liver enzyme concentrations, insulin sensitivity,
and intra-abdominal fat (IAF) distribution.
RESEARCH DESIGN AND METHODS — Plasma γ-glutamyl transferase (GGT), aspartate transaminase (AST), alanine transaminase (ALT) levels, insulin sensitivity
(insulin sensitivity index [ S I ]), IAF area, and subcutaneous fat (SCF) area were measured in 177 nondiabetic subjects (75 men and 102 women, aged 31–75
years) with no history of liver disease. On the basis of BMI (< or ≥27.5 kg/m 2 ) and S I (< or ≥7.0 × 10 −5 min/pmol) subjects were divided into lean insulin sensitive (LIS, n = 53), lean insulin resistant (LIR, n = 60), and obese insulin resistant (OIR, n = 56) groups.
RESULTS — Levels of all three liver enzymes were higher in men than in women ( P < 0.0001 for each). In men, GGT levels were higher in insulin-resistant than in insulin-sensitive subjects ( P < 0.01). In women, GGT levels were higher in the OIR than in the LIS group ( P < 0.01) but no different in the LIR group. There was no difference in ALT and AST levels among the LIS, LIR, and OIR groups.
GGT was associated with S I (r = −0.26, P < 0.0001), IAF area ( r = 0.22, P < 0.01), waist-to-hip ratio (WHR) ( r = 0.25, P = 0.001), BMI ( r = 0.17, P < 0.05), and SCF area ( r = 0.16, P < 0.05) after adjustments for age and sex. In men, only S I ( r = −0.29, P < 0.05) remained independently correlated with GGT in multiple regression analysis. In women, IAF area ( r = 0.29, P < 0.01) and WHR ( r = 0.29, P < 0.01) were independently associated with GGT, but S I was not.
CONCLUSIONS — In nondiabetic men GGT but not AST or ALT levels, are inversely related to insulin sensitivity independent of IAF area.
However in women, GGT is related to measures of central body fat rather than to insulin sensitivity.
ALT, alanine aminotransferase
AST, aspartate aminotransferase
FSIGT, frequently sampled intravenous glucose tolerance test
GGT, γ-glutamyl transferase
IAF, intra-abdominal fat
IQR, interquartile range
LIR, lean insulin resistant
LIS, lean insulin sensitive
NAFLD, nonalcoholic fatty liver disease
NASH, nonalcoholic steatohepatitis
OIR, obese insulin resistant
SCF, subcutaneous fat
SI, insulin sensitivity index
WHR, waist-to-hip ratio
Footnotes
Published ahead of print at http://care.diabetesjournals.org on 31 July 2007. DOI: 10.2337/dc06-1758.
T.M.W., K.M.U., and J.T. contributed equally to this work.
A table elsewhere in this issue shows conventional and Système International (SI) units and conversion factors for many substances.
The costs of publication of this article were defrayed in part by the payment of page charges. This arti...

Relationship of Liver Enzymes to Insulin Sensitivity and Intra-Abdominal Fat

10.2337/dc06-1758