Figure 1.

Nicotine (Nic) perfusion induces IR and lower adiposity. (a) IPGTT, insulin release, and ITT; n = 10–11 each. (b,c) Hyperinsulinemic-euglycemic (H-E) clamp. Glucose infusion rate (GIR), hepatic glucose production (HGP), the rate of the disappearance (R_d) and the glucose metabolic index (R_g) in tibialis anterior and soleus (b) or epididymal white adipose tissue (eWAT, c); n = 9 each. (d) Body weight changes; n = 11 each. (e) Representative MRI images (n = 4 each) for fat distribution, fat mass and lean mass (n = 11 each). Scale bars, 1 cm. (f) Representative eWAT sections (n = 10 sections each) and quantification of adipocyte diameter (Scale bars, 50 µm, n = 10 each), and temperature of brown adipose tissue (BAT) area and rectal temperature (n = 10 each) with representative infrared thermal images (Scale bars, 1 cm). (g) Serum FFA after overnight fasting or insulin perfusion at 40 min during ITT (n = 10 each), and the linear regression between fat mass and serum FFA levels during insulin perfusion (n = 10 each). (h) In vivo lipolysis. (n = 8 each). (i) In vitro lipolysis assay of isolated adipocytes; n = 7 each. (j) Respiratory quotients (RQ, VCO₂/VO₂) (left) and the average data (right). n = 10 each. Significance determined by one-way ANOVA with repeated measures for the inter-assay evaluations (a,b,d,h), Student’s t-test (c,e,f,j), one-way ANOVA with Bonferroni’s post-hoc test (g,i) and *P < 0.05. All values are means ± SEM.