Fig. 5: Obesity alters circulating and adipose serotonin concentrations during cold exposure in humans.
From: The serotonin transporter sustains human brown adipose tissue thermogenesis
a, Circulating plasma serotonin concentrations during warm conditions (red columns) and mild cold exposure (16–17 °C; blue columns) in normal weight BAT-positive men (n = 11). b–d, Serotonin levels were measured in platelet-poor plasma (b) (n = 17), platelets (c) (n = 17) and abdominal WAT (d) (n = 20) during warm (red columns) and cold (blue columns) conditions in normal weight (closed circles) and obese (open circles) participants. Male and female participants are depicted by black and red circles, respectively. e–h, Circulating hormones/intermediates were measured in normal weight and obese participants (n = 10 biologically independent participants per group) during warm and cold exposure: circulating noradrenaline (e), NEFAs (f), insulin (g) and glucose (h). Data are mean ± s.e.m. and were analysed by paired t-test (a) and two-way-repeated measures ANOVA (b–h). Insulin (g) was greater in obese participants (P < 0.0001 at all time points); otherwise, significant P values are detailed in the respective panels.
