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Horm Metab Res 2001; 33(12): 708-712
DOI: 10.1055/s-2001-19132
Original Basic
© Georg Thieme Verlag Stuttgart · New York

Elevated AT1 Receptor Protein but Lower Angiotensin II-Binding in Adipose Tissue of Rats with Monosodium Glutamate-Induced Obesity

L'. Pintérová 1 , B. Železná 2 , M. Ficková 1 , L. Macho 1 , O. Križanová 3 , D. Ježová 1 , Š. Zórad 1
  • 1 Institute of Experimental Endocrinology, SAS, Bratislava, Slovak Republic
  • 2 Institute of Molecular Genetics, ASCR, Prague, Czech Republic
  • 3 Institute of Molecular Physiology and Genetics, Bratislava, Slovak Republic
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Publication Date:
18 December 2001 (online)

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Age-related hypertrophy of adipose tissue has been associated with a significant decrease in the number of angiotensin II receptors. The aim of this study was to investigate the characteristics of angiotensin II receptors in hypertrophic adipose tissue in animal obesity model using rats postnatally treated with monosodium glutamate. Angiotensin II is known to induce hypertrophy in several tissues of the cardiovascular system and might do the same in fat tissue. The expression and binding properties of angiotensin II AT1 receptors in epididymal fat tissue of adult rats were studied using membrane-binding, RT-PCR, and immunoblotting. The amount of AT1 receptor mRNA did not differ significantly between obese and control rats. Despite that glutamate-treated rats displayed approximately 4-times more AT1 receptor immunoreactive protein content in fat tissue cell membranes than the controls did. In contrast, binding experiments showed a significant (40.3 ± 6.2 %) decrease of 125I-Sar1-Ile8-angiotensin II-binding to fat tissue cell membranes in obese rats compared to controls. In conclusion, the present study provides evidence for the low binding properties associated with an accumulation of AT1 receptor protein in cell membranes of the fat tissue of rats with glutamate-induced obesity. Discrepancies among angiotensin II-binding, AT1 receptor protein, and AT1 receptor mRNA levels indicate a possible defect in the receptor protein, which remains to be identified. The results obtained support a role of angiotensin II and AT1 receptors in the pathogenesis of obesity.

Key words:

AT1 Receptor - Fat Tissue - MSG Rat

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Štefan Zórad

Institute of Experimental Endocrinology
Slovak Academy of Sciences

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