Brown adipose tissue thermogenesis in women with polycystic ovary syndrome.

Polycystic ovary syndrome (PCOS), the most common endocrinopathy of reproductive age women, is characterized by reproductive, metabolic and psychological features exacerbated by weight gain. Weight management in PCOS is challenged by greater propensity to weight gain and lack of sustainable dietary interventions. Metabolically active brown adipose tissue (BAT) has been described in humans. The sympathetic nervous system and sex hormones play role in modulating the thermogenic activity of BAT. Human studies confirmed the association of supraclavicular skin temperature, where most human BAT is located, with BAT activity. BAT activity and modulation has not been studied in PCOS. This observational study aimed to explore BAT thermogenesis and its associations in PCOS. Cutaneous wireless temperature probes (2 cm diameter, 0.5 depths) were taped to supraclavicular (BAT) and upper arm (muscle) regions of 49 premenopausal women with PCOS, over 96 hours, (mean age: 29.85 +/- 5.93, mean BMI: 29.02 +/- 5.43), recruited from community setting. Multiunit muscle SNS activity (MSNA by microneurography) and plasma noradrenaline were measured as markers of SNS activity. Fasting lipids and serum androgens were measured. An oral glucose tolerance test was performed to quantify insulin resistance (IR) using Homeostatic Model Assessment of Insulin Resistance (HOMA-IR). Recorded temperature data were available in 41 participants. Mean supraclavicular temperature was significantly higher than mean arm temperature (33.87 +/- 0.64 vs 32.28 +/- 0.76, P < .001). Supraclavicular temperature correlated with noradrenaline and triglyceride levels (r2 = -.435, P = .008 and r2 = -.392, P = .010 respectively) which remained significant after adjustment for BMI. Total testosterone significantly correlated with supraclavicular temperature after adjustment for BMI (r2 = -.598, P = .011). Arm temperature did not correlate with noradrenaline, triglyceride and androgens. This is the first study of BAT the