engleski

Expression of adipokines and their receptors in brain and adipose tissue of rats with genetically altered serotonergic homeostasis

There is a trend of a substantial rise in obesity in the world population. Obesity is a disease characterized by excessive adipose tissue accumulation in the body. Central serotonin (5-hydroxytryptamine, 5HT) has been historically involved in regulation of energy intake and consumption, while the role for peripheral 5HT in body weight regulation has been suggested just recently. In our research we use Wistar-Zagreb 5HT (WZ- 5HT) rats, an animal model with constitutively high or low activity of peripheral 5HT transporter (termed high-5HT and low-5HT subline), developed by selective breeding of animals toward extremes of platelet 5HT uptake velocity. Besides in periphery, two sublines of WZ-5HT rats differ also in the central 5HT homeostasis, as evidenced from neurochemical and behavioral studies. Animals from 5HT- sublines show clear differences in obesity phenotypes, with high- 5HT subline displaying lifelong elevated body weight and a clear adult obesity in comparison to the low-5HT animals. In our previous experiments by the use of real- time PCR arrays we have investigated expression levels of over 160 genes known to be implicated in the regulation of adipogenesis, energy expenditure and orexigenic and anorectic pathways. The aim of this study was to confirm the results obtained by gene expression profiling. The expression of adipocytokines (leptin, resistin, adiponectin) and their receptors was assessed in hypothalami and visceral adipose tissue of animals from high- 5HT and low-5HT sublines using quantitative real-time PCR. Relative expression levels of mRNAs encoding leptin (p=0, 0027), resistin (p=0, 0058), adiponectin (p=0, 0030), adiponectin 1 (p=0, 0410) and adiponectin 2 (p=0, 1556) receptors in visceral adipose tissue were higher in animals from high-5HT subline in comparison to the animals from low-5HT subline. On the other hand, there were no statistically significant differences between the sublines in hypothalamic expression of adiponectin (p=0, 1593), adiponectin 1 (p=0, 4891) and adiponectin 2 (p=0, 8357) receptors. The results show that differences in the expression levels of investigated genes are tissue specific, and these sublines may represent an interesting model for investigating a role of constitutive differences in central/peripheral 5HT signaling in the modulation of body weight.

obesity; serotonin; Wistar-Zagreb 5HT rats

nije evidentirano