Tohoku J. Exp. Med., 2009, 219(4)

Upregulation of Tanis mRNA Expression in the Liver is Associated with Insulin Resistance in Rats

JIE LIU,¹ HUIQIN TANG,¹ LI NIU¹ and YANCHENG XU¹

¹Department of Endocrinology, Zhongnan Hospital of Wuhan University, Wuhan, Hubei, China

Tanis, a newly discovered membrane protein, has been suggested to be involved in the development of insulin resistance (IR). In addition, Tanis was postulated as a hepatic receptor for an inflammatory marker, serum amyloid A-1 (SAA1), which represents a risk factor for cardiovascular disease. The aim of this study was to investigate the potential role of Tanis and SAA1 in the development of IR using a rat model. Male Sprague-Dawley (6 weeks old) rats were divided into three groups (n = 10 for each group): control, IR, and rosiglitazone-treated IR. Rosiglitazone is an insulin sensitizer that is used for treatment of type 2 diabetes. Rats were fed a high-fat diet for 35 days to induce IR, as judged by increased plasma glucose and insulin concentrations, following an oral glucose tolerance test. Rats of three groups were sacrificed, and the livers were dissected for RNA preparation. Real-time PCR analysis revealed that Tanis and SAA1 mRNA levels were significantly higher in the livers of IR rats than those of control rats fed a standard diet and those of IR rats treated for 35 days with rosiglitazone. Importantly, there was no significant difference in Tanis and SAA1 mRNA levels between control and rosiglitazone-treated IR rats. Furthermore, the expression levels of Tanis mRNA are positively correlated with those of SAA1 mRNA in the livers of control, IR and rosiglitazone-treated IR rats. In conclusion, high expression of Tanis mRNA in the liver is associated with the development of IR probably via the function of SAA1.

keywords —— high-fat diet; insulin resistance; Tanis; SAA1; inflammation.

© 2009 Tohoku University Medical Press

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Tohoku J. Exp. Med., 2009, 219, 307-310

Correspondence: Yancheng Xu, Department of Endocrinology, Wuhan University, 169# Donghu Road, Hubei province, China, 430071.

e-mail: othq@hotmail.com