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Role of NADH-cytochrome b_5 reductase in biosynthesis of thyroid hydrogen peroxide

Huang Guoliang, Zhang Geng, Gao Yan, Zhu Jinwei

Union Hospital of Fujian Medical University and Fujian Provincial Endocrinology Institute,Fuzhou(350001)；School of Pre-Clinical Medicine, Fujian Medical University,Fuzhou(350004)；Department of Endocrinology, the First Hospital, Peking University.Beijing(100034)

Abstract

The activity of NADH-cytochrome b_5 reductase (b_5R) and the levels of hydrogen peroxide in the thyroid of patients with Graves^ disease (GD) and normal controls were measured with potassium ferricyanide as substrate and with the homovanilic acid fluorescence assay. The activity of b_5R and the level of H_2O_2 in GD thyroid were definitely higher than those in normal thyroid. After addition of catalase in GD thyroid was not signigicantly different from that in normal thyroid. After addition of p-chloromercuribenzoate, a b_5R inhibitor, the activity of b_5R in GD and normal thyroid decreased by 85, the level of H-2O_2 decreased by 50%, and protein-bound iodine (PBI) formation by 52%. There is a positive correlation between the level of H_2O_2 and the activity of b_5R. Our data indicate that b_5R participates in thyroid hydrogen peroxide biosynthesis, and is an important emzyme in the production of H_2O_2.

Key words: NADH-cytochrome b_(5) reductase;Hydrogen peroxide;Graves' disease

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Citing This Article：

Huang Guoliang, Zhang Geng, Gao Yan, Zhu Jinwei. Role of NADH-cytochrome b_5 reductase in biosynthesis of thyroid hydrogen peroxide. Acta Physiol Sin 2002; 54 (4): (in Chinese with English abstract).