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ARS Home » Plains Area » Grand Forks, North Dakota » Grand Forks Human Nutrition Research Center » Dietary Prevention of Obesity-related Disease Research » Research » Publications at this Location » Publication #271964
Title: Glutathionylation of hepatic and visceral adipose proteins decreases in obese-prone, glucose intolerant rats

Author
item Picklo, Matthew
item Jackson, Matthew
item Idso, Joseph

Submitted to: Free Radicals in Biology and Medicine
Publication Type: Abstract Only
Publication Acceptance Date: 9/9/2011
Publication Date: 11/1/2011
Citation: Picklo, M.J., Jackson, M.I., Idso, J.P. 2011. Glutathionylation of hepatic and visceral adipose proteins decreases in obese-prone, glucose intolerant rats. Free Radicals in Biology and Medicine. SFRBM's 18th Annual Meeting: Program and Abstracts; 51(Supplement); S65.

Interpretive Summary:

Technical Abstract: Obesity and insulin resistance are associated with increases in oxidative stress and lipid peroxidation. On the other hand, adipocytes from obese animals have elevated GSH content, and insulin resistance can be reversed by GSH depletion. Oxidation of active site cysteines of protein tyrosine phosphatases (PTP) improves insulin sensitivity indicating that limited levels of protein thiol oxidation have beneficial physiological properties. We tested the hypothesis that the oxidized thiol content of proteins from tissues important to glucose uptake is decreased in obesity. This study utilized obese-prone Sprague-Dawley (OPSD) rats that developed obesity and glucose intolerance when fed a high-fat (45% fat calories) diet versus OPSD rats fed a control, normal fat (10% fat calories) diet. Liver, visceral (peri-renal) adipose and skeletal (gastrocnemius) muscle were studied. Proteins from these tissues were analyzed for content of sulfenic acids (PSOH), protein glutathione disulfides (PSSG), and PTP-based sulfonic acids (oxPTP) by dot blot and immunoblot methods. Hepatic proteins from obese animals demonstrated a decrease in PSSG (45%) and oxPTP (40%) content versus the control animals while there was no change in PSOH. There was no obvious change in the masses of modified proteins as assessed by western blot. Like liver, adipose proteins from obese rats showed a decrease in PSSG (26%) content but not PSOH or oxPTP. There were no changes in the PSOH, PSSG, or oxPTP in skeletal muscle. PSSG is reduced by glutaredoxin (GRX) activity. However there was no difference in hepatic and muscular GRX activity or GRX-1 protein content between obese and control animals. While GRX activity was not detectable in adipose tissue, GRX-1 content was increased 72% in visceral adipose from obese animals. Our data indicate that glutathionylation of proteins is decreased in select tissues in the obese state in some cases by elevated GRX-1. These data suggest that obesity alters protein redox state in a tissue-specific manner during obesity and that reduced protein thiol oxidation may influence obesity-induced pathology.