Background: Although the importance of gender as a key determinant in health and illness has been recognized for a long time, systematic studies of gender differences in medicine are still lacking. We hypothesized that interscapular brown adipocyte tissue (BAT), is not only a key tissue contributing to energy expenditure, but also regulates diet-induced thermogenesis, and may be an ideal target for studying gender differences in obesity development in response to a high fat diet (HFD). Methods: We therefore performed differential proteome analysis of BAT from lean and obese rats of both genders fed a HFD using 2-DE combined with MALDI-TOF-MS. Results: When exposed to a HFD, male rats gained more body weight with increased values of plasma biochemical parameters than did female rats. Among 595 matched spots, 48 differentially expressed identified spots showed significant gender differences, whereas 7 proteins showed no gender differences, but did show a HFD response. Conclusions: Proteomic investigations into gender-dimorphic protein modulation in BAT may provide conclusive results showing higher expression of numerous proteins involved in thermogenesis and fat oxidation as well as lower expression of proteins contributing to fat synthesis in female rats than in male rats.

One of the major issues in the field of obesity is why some humans become obese and others resist development of obesity when exposed to high-calorie diets. Despite the same genetic background, namely obesity-prone (OP) and -resistant (OR) rats, differing responses have been demonstrated in a high fat diet-induced rodent model. The aim of the present study was to discover novel obesity-related biomarkers for susceptibility and/or resistance to obesity by proteomic analysis of OP and OR rat plasma. After feeding of high fat diet, OP rats gained approximately 25% more body weight than OR rats and were used for proteomic analysis using 2-DE combined with MALDI-TOF-MS. We categorized identified proteins into three groups by analysis of both average spot density in each group and individual spot density of six rats as a function of body weight. Consequently, category (1) included inter-α-inhibitor H4 heavy chain and fetuin B precursor, which can be used as novel plasma biomarkers for risk of obesity. Nine proteins of category (2) and (3) can also be plausible plasma markers in the study of obesity. This proteomic study is an important advancement over the previous steps needed for identification of OP and OR rats.

Background: Proper understanding of molecular mechanisms underlying gender dimorphism in obesity for better nutritional recommendation is still in early stages. As white adipose tissues (WAT) is most important tissue in obesity metabolism, comparative proteomic analysis of all three WAT deposits at the same time to yield immensely important protein markers was the primary goal of this study. Methods: We performed differential expression analysis of protein profiles of three different WAT viz. subcutaneous, inguinal, and abdominal fat deposits of both genders in lean and obese rats fed a high fat diet (HFD) using a combination of 2-DE and MALDI-TOF-MS. Results: The proteomics analysis enabled us to detect 25, 29, and 46 proteins showing gender differences in three WAT deposits, respectively, to gain insight into cause of higher body weight gain in male in response to HFD. Conclusion: The gender dimorphism found in this proteomic study implies that female rats have a lower tendency to undergo metabolic syndrome manifestation, which is associated with lower reliance on lipid as an energy fuel, lower lipogenesis, as well as increased mitochondrial oxidative capacity. In conclusion, most of the candidate proteins identified herein by differential proteomics were previously unrecognized in gender dimorphism of adipose tissue.

Gender differences in obesity stem from metabolic and hormonal differences between sexes and contribute to differences between women and men in health risks attributable to obesity. We hypothesized that liver may be an ideal target for the evaluation of gender differences in obesity development in response to a high-fat diet (HFD). Therefore, to test this hypothesis, we performed a global proteome analysis in the liver of lean and obese rats of both genders who were fed an HFD through 2-DE combined with MALDI-TOF-MS. When rats were exposed to HFD, male rats gained more body weight with increased values of plasma biochemical parameters than female rats. Image analysis and further statistical analysis of a 2-DE protein map allowed for the detection and identification of 34 proteins that were significantly modulated in a gender-dependent manner. We found 19 proteins showing identical gender-different regulation in both normal diet (ND) and HFD. Five proteins also showed clear gender differences in both ND and HFD; however, their regulation modes in HFD were opposite to those in ND. Of particular interest, 10 proteins showed gender differences only in either ND or HFD rats. Present proteomic insight into gender-dimorphic protein modulation in liver would aid in the improvement of gender awareness in the health-care system and in implementation of evidence-based gender-specific clinical recommendations.

Background: Although it has been believed for a long time that gender differences in physiology and metabolism were not relevant beyond the reproductive system, new research has indicated that sexual dimorphism may be more prevalent than previously believed. Therefore, the goal of this study was to develop a global view of the changes in gender-dependent protein abundance in two different types of skeletal muscles (soleus and gastrocnemius) of lean and high fat diet (HFD)-induced obese rats. Methods: To examine differential expression of proteins between gender and diet, we performed differential proteome analysis of skeletal muscle from lean and obese rats of both genders fed a HFD using 2-DE combined with MALDI-TOF-MS. Results: Our gender-specific proteome comparison showed that male and female rats displayed different patterns of proteome regulation including proteins involved in muscle contraction, carbohydrate and lipid metabolism, oxidative phosphorylation, as well as detoxification and antioxidant defenses. Conclusions: most of the candidate proteins identified herein by differential proteomics were previously unrecognized in gender dimorphism of skeletal muscle. Our data can serve as the basis for specific evidence-based interventions allowing for the prevention and treatment of obesity by matching the different needs of women and men such as the development of gender-based medicine.