Background Obesity is known to be associated with higher risks of

Background Obesity is known to be associated with higher risks of cardiovascular disease, metabolic syndrome, and diabetes mellitus. mice (C57/BL6) by high-fat diet feeding and found that the TSHR protein expression in visceral adipose tissues from obesity mice was significantly higher in comparison with the non-obesity control mice ( em P /em 0.05). Finally, the TSHR expression in adipose tissues was decided in 120 patients. The results showed that TSHR expression in subcutaneous adipose tissue is usually correlated with BMI (body mass index). Conclusion Taken together, these results suggested that TSHR is an important regulator of adipocyte differentiation. Dysregulated expression of TSHR in adipose tissues is associated with obesity, which may involve a mechanism of extra adipogenesis. AZD2171 manufacturer strong class=”kwd-title” Keywords: TSHR, obesity, adipogenesis Background Obesity, a condition of body characterized by over accumulation of fat, is usually associated with increased risks of cardiovascular disease, metabolic syndrome, and diabetes mellitus [1,2]. However, the mechanism of obesity development is not fully comprehended, and has become a focus of extensive investigations. Generally, obesity occurs when energy intake by an individual exceeds the rate of energy expenditure. Adipose tissues are the major depots for energy storage. Obesity is known to be directly linked to the accumulation of body fat. At the cellular level, obesity can be considered as a hypertrophic disease resulted from an increase in the number or size of individual adipocytes. New excess fat cells come from a preexisting populace of undifferentiated progenitor with high capability of proliferation and differentiation. So far, numerous factors or proteins have been implicated in the generation of new excess fat cells, including peroxisome proliferator-activated receptor (PPAR-, a member of the nuclear hormone receptor), CCAAT/enhancer binding protein (C/EBP, including C/EBP a, C/EBP and C/EBP), adipocyte lipid binding protein AZD2171 manufacturer (ALBP) and adipocyte determination and differentiation factor 1 (Put1) [3-5]. However, the relevance of those factors to obesity is usually unclear. Thyroid-stimulating hormone (TSH) receptor gene ( em TSHR /em ) Rabbit Polyclonal to SHP-1 (phospho-Tyr564) encodes a transmembrane receptor which belongs to a subfamily of heptahelical G protein coupled receptors. In thyroid tissues, TSHR mediates the effects of TSH released from the anterior pituitary, and plays crucial functions in thyroid development and function. Recent AZD2171 manufacturer studies have exhibited that TSHR is also present in non-thyroid tissues, such as hepatocyte [6] and adipocytes [7,8]. However, the physiological or pathological relevance of TSHR in these non-thyroid tissues is not completely known and is now under intensive investigations [9-12]. Several studies have suggested that TSHR expression in adipocytes may play an important role for adipogenesis. T. Onaya reported that this differentiation of rat preadipocytes was accompanied by an increased expression of TSHR [7]. Comparable results were also observed in human orbital preadipocyte fibroblasts [13,14] and in mouse embryonic stem cells [15]. However, there have been reports showing TSHR expression was negatively correlated with adipogenesis [9]. The reason for the discrepancy in the above observations is unknown. In the present study, the association between adipocyte differentiation and TSHR expression was investigated in murine 3T3-L1 preadipocytes. In addition, we determined the TSHR expression in adipose AZD2171 manufacturer tissues from both mice and human samples, and the relevance of TSHR expression in adipocytes to obesity was evaluated. Results Induction of differentiation in 3T3-L1 preadipocytes 3T3-L1 preadipocytes were induced to differentiate as described in Materials and Methods. The differentiation was evaluated by Oil-red-O staining for lipid accumulation and by RT-PCR analyses of PPAR- and ALBP mRNA expression. As shown in Figure ?Figure11 (A, B), lipid droplets could be detected by Oil-red-O staining as early as day-4 post differentiation induction, and peaked on day-12. To further verify the preadipocyte differentiation, the expression of PPAR- and ALBP, two essential regulators and markers for adipocyte differentiation, was analyzed by RT-PCR. As shown in Figure 1(C, D), the mRNA levels of PPAR- and ALBP were significantly increased on day-2 post induction of differentiation, and peaked on day-12 ( em P /em 0.05). Open in a separate window Figure 1 Adipose differentiation of 3T3-L1 preadipocytes. Adipose differentiation of.