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Wang Y, Nakagawa Y, Liu L, Wang W, Ren X, Anghel A, Lutfy K, Friedman TC, Liu Y. Tissue-specific dysregulation of hexose-6-phosphate dehydrogenase and glucose-6-phosphate transporter production in db/db mice as a model of type 2 diabetes. Diabetologia 2011; 54:440-50. [PMID: 21052977 PMCID: PMC3795617 DOI: 10.1007/s00125-010-1956-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2010] [Accepted: 09/28/2010] [Indexed: 01/15/2023]
Abstract
AIMS/HYPOTHESIS Tissue-specific amplification of glucocorticoid action through 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) affects the development of the metabolic syndrome. Hexose-6-phosphate dehydrogenase (H6PDH) mediates intracellular NADPH availability for 11β-HSD1 and depends on the glucose-6-phosphate transporter (G6PT). Little is known about the tissue-specific alterations of H6PDH and G6PT and their contributions to local glucocorticoid action in db/db mice. METHODS We characterised the role of H6PDH and G6PT in pre-receptor metabolism of glucocorticoids by examining the production of the hepatic 11β-HSD1-H6PDH-G6PT system in db/db mice. RESULTS We observed that increased production of hepatic H6PDH in db/db mice was paralleled by upregulation of hepatic G6PT production and responded to elevated circulating levels of corticosterone. Treatment of db/db mice with the glucocorticoid antagonist RU486 markedly reduced production of both H6PDH and 11β-HSD1 and improved hyperglycaemia and insulin resistance. The reduction of H6PDH and 11β-HSD1 production by RU486 was accompanied by RU486-induced suppression of hepatic G6pt (also known as Slc37a4) mRNA. Incubation of mouse primary hepatocytes with corticosterone enhanced G6PT and H6PDH production with corresponding activation of 11β-HSD1 and PEPCK: effects that were blocked by RU486. Knockdown of H6pd by small interfering RNA showed effects comparable with those of RU486 for attenuating the corticosterone-induced H6PDH production and 11ß-HSD1 reductase activity in these intact cells. Addition of the G6PT inhibitor chlorogenic acid to primary hepatocytes suppressed H6PDH production. CONCLUSIONS/INTERPRETATION These findings suggest that increased hepatic H6PDH and G6PT production contribute to 11β-HSD1 upregulation of local glucocorticoid action that may be related to the development of type 2 diabetes.
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Affiliation(s)
- Y. Wang
- Division of Endocrinology, Metabolism & Molecular Medicine, Charles Drew University of Medicine & Sciences, UCLA School of Medicine, 1731 E. 120th St, Los Angeles, CA 90059, USA
| | - Y. Nakagawa
- Department of Pediatrics, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - L. Liu
- Department of Endocrinology & Metabolism, Shanghai Jiaotong University Affiliated Sixth People’s Hospital, Shanghai Diabetes Institute, Shanghai, People’s Republic of China
| | - W. Wang
- Division of Endocrinology, Metabolism & Molecular Medicine, Charles Drew University of Medicine & Sciences, UCLA School of Medicine, 1731 E. 120th St, Los Angeles, CA 90059, USA
| | - X. Ren
- Division of Endocrinology, Metabolism & Molecular Medicine, Charles Drew University of Medicine & Sciences, UCLA School of Medicine, 1731 E. 120th St, Los Angeles, CA 90059, USA
| | - A. Anghel
- Division of Endocrinology, Metabolism & Molecular Medicine, Charles Drew University of Medicine & Sciences, UCLA School of Medicine, 1731 E. 120th St, Los Angeles, CA 90059, USA
| | - K. Lutfy
- Division of Endocrinology, Metabolism & Molecular Medicine, Charles Drew University of Medicine & Sciences, UCLA School of Medicine, 1731 E. 120th St, Los Angeles, CA 90059, USA
| | - T. C. Friedman
- Division of Endocrinology, Metabolism & Molecular Medicine, Charles Drew University of Medicine & Sciences, UCLA School of Medicine, 1731 E. 120th St, Los Angeles, CA 90059, USA
| | - Y. Liu
- Division of Endocrinology, Metabolism & Molecular Medicine, Charles Drew University of Medicine & Sciences, UCLA School of Medicine, 1731 E. 120th St, Los Angeles, CA 90059, USA
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