Metabolic and hemodynamic response of adipose tissue to angiotensin II

Objective: Recent studies have revealed the presence of a local renin-angio tensin system in adipose tissue. To examine the possible role of this syste m in adipose tissue, we performed microdialysis studies on the effect of an giotensin II (Ang II) on blood flow and metabolism in abdominal subcutaneou s adipose tissue (aSAT) and femoral subcutaneous adipose tissue (fSAT) in y oung healthy men. Research Methods and Procedures: Using the microdialysis technique, two dif ferent protocols were run perfusion with Ringer's solution + 50 mM ethanol with the subsequent addition of 125, 250, and 500 mug/liter Ang II (n=8) an d Ringers's solution + 50 mM ethanol with the subsequent addition of isopro terenol (I AM) alone and in combination with 500 mug/liter Ang II (n=6). Di alysate concentrations of ethanol, glycerol, glucose, and lactate were meas ured for estimating blood flow (ethanol dilution technique), lipolysis, and glycolysis, respectively. Results: Perfusion with Ang Il resulted in a dose-dependent decrease in blo od flow (fSAT > aSAT), lipolysis (fSAT > aSAT), and glucose uptake (fSAT = aSAT). Isoproterenol increased blood flow and lipolysis at both sites and t hose effects could be returned to baseline values by the addition of Ang II in aSAT but not fSAT. Discussion: In conclusion, our data indicate that in addition to its well-k nown vasoconstricting effect, Ang II inhibits lipolysis in adipose tissue, whereby femoral fat depots seem to be more sensitive to this effect than ab dominal depots.