Sexual dimorphism in adipose tissue function as evidenced by circulating adipokine concentrations in the fasting state and after an oral glucose challenge.

STUDY QUESTION: Do the circulating levels of a panel of adipokines involved in glucose metabolism exhibit sexual dimorphism in the fasting state and after an oral glucose load? SUMMARY ANSWER: Our results indicate sexual dimorphism in the circulating concentrations of adipokines involved in intermediate metabolism in the fasting state and during an oral glucose load. This finding suggests an influence of sex steroids on adipose tissue function. WHAT IS KNOWN ALREADY: Sexual dimorphism in adipose tissue distribution fully develops after puberty and modulates the risk for cardiometabolic disorders. However, the possibility that adipose tissue function exhibits sexual dimorphism as well as its distribution is unproved. STUDY DESIGN, SIZE, DURATION: Cross-sectional case-control study including 32 subjects. PARTICIPANTS/MATERIALS, SETTING,
METHODS: Sixteen subjects with weight excess (8 men and 8 women, including 4 overweight and 4 obese subjects in each group) and 16 normal weight healthy volunteers (8 men and 8 women) presenting with similar age were submitted to a 75-g oral glucose tolerance test (oGTT). We measured circulating concentrations of insulin, glucose, chemerin, lipocalin-2, omentin-1, leptin and adiponectin and calculated their areas under the oGTT curve (AUC). MAIN RESULTS AND THE ROLE OF CHANCE: Leptin and adiponectin concentrations were higher throughout the oGTT in women compared with men. Lipocalin-2 concentrations decreased during the oGTT in the whole group of study subjects. However, these levels remained higher in men with weight excess compared with normal weight men, whereas in women with weight excess lipocalin-2 levels at the end of the oGTT were lower compared with normal weight women. Sex was among the main determinants of the AUC of omentin-1 and leptin in linear regression models, and lower estradiol and testosterone concentrations were related to higher AUC of chemerin and omentin-1, respectively. Subjects with weight excess had higher AUC of chemerin and leptin and lower AUC of omentin-1 and adiponectin levels, independently of sex. LIMITATIONS, REASONS FOR CAUTION: We included a relatively small sample size and, because this was a cross-sectional study, we cannot infer causality to the associations between the changes in circulating adipokine concentrations and the variables studied here. WIDER IMPLICATIONS OF THE
FINDINGS: Sexual dimorphism in adipose tissue function should be considered when studying adiposity and obesity, and also when designing strategies for their diagnosis and management.