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Effect of Insulin, the Glutathione System, and Superoxide Anion Radical in Modulation of Lipolysis in Adipocytes of Rats with Experimental Diabetes

V. V. Ivanov, E. V. Shakhristova*, E. A. Stepovaya, O. L. Nosareva, T. S. Fedorova, N. V. Ryazantseva, and V. V. Novitsky

Siberian State Medical University, Moskovskii Trakt 2, 634050 Tomsk, Russia; fax: 8 (3822) 53-3309; E-mail: office@ssmu.tomsk.ru; shaxristova@yandex.ru

* To whom correspondence should be addressed.

Received May 14, 2014; Revision received July 18, 2014
Spontaneous lipolysis was found to be increased in adipocytes of rats with alloxan-induced diabetes. In addition, isoproterenol-stimulated hydrolysis of triacylglycerols was inhibited against the background of oxidative stress and decreased redox-status of cells. A decrease in the ability of insulin to inhibit isoproterenol-stimulated lipolysis in adipocytes that were isolated from adipose tissue of rats with experimental diabetes was found, which shows a disorder in regulation of lipolysis in adipocytes by the hormone in alloxan-induced diabetes. Based on these findings, we concluded that there is an influence of reactive oxygen species, superoxide anion radical in particular, and redox potential of the glutathione system on molecular mechanisms of change in lipolysis intensity in rat adipocytes in alloxan-induced oxidative stress. Activation of spontaneous lipolysis under conditions of oxidative stress might be a reason for the high concentration of free fatty acids in blood plasma in experimental diabetes, and this may play a significant role in development of insulin resistance and appearance of complications of diabetes.
KEY WORDS: diabetes mellitus, adipocyte, oxidative stress, lipolysis, glutathione system, Mn-tetra(N-methyl-4-pyridyl)porphyrin, N-ethylmaleimide

DOI: 10.1134/S0006297915010101