Browning of White Adipose Tissue Uncouples Glucose Uptake from Insulin Signaling
Figure 3
Brite adipose cells and tissues exhibit elevated glucose uptake independent of insulin stimulation, thereby enhancing glucose clearance from blood.
(A, B) 3H-2-deoxy-D-glucose (3H-2DOG) uptake by primary inguinal white adipose tissue (iWAT) precursor cells (A) absolute or (B) relative to unstimulated basal uptake. Cells were differentiated into white (EtOH treated) or brite (cPGI2 treated) adipocytes for 8 days and stimulated with different doses of Insulin for 20 minutes. (C, D) Intraperitoneal insulin (Ins) tolerance test (0.5 U/kg body weight insulin) of mice treated with CL316,243 (CL, 1 µg/g/day) or NaCl via s.c. implanted osmotic pumps for 10 days. (C) Absolute blood glucose levels and (D) levels relative to non-insulin-stimulated are shown. (E, F) 3H-2DOG uptake rate into inguinal or abdominal white (iWAT, aWAT) or brown (BAT) adipose tissue and heart of the same mice as in B, C. (E) Absolute uptake and (F) uptake relative to non-insulin-stimulated conditions is shown. Uptake rates were measured 45 minutes after intraperitoneal injection of insulin or vehicle. All values are expressed as means ± SEM, n = 3–6, #p<0.05, ##p<0.01, ###p<0.001 white vs. brite, *p<0.05, **p<0.01, ***p<0.001 no insulin vs. insulin stimulated.