Medizinische Universität Graz Austria/Österreich - Forschungsportal - Medical University of Graz
Gewählte Publikation:
Weinhandl, H.
Effect of physiological hyperinsulinemia on tissue perfusion
[ Dissertation ] Medical University of Graz; 2008. pp.
- Autor*innen der Med Uni Graz:
- Weinhandl Heinz
- Betreuer*innen:
- Ellmerer Martin
- Pieber Thomas
- Altmetrics:
- Abstract:
- Insulin has been reported to increase blood flow and tissue recruitment for small solutes such as glucose in insulin-sensitive tissues. Objective of the present study was to investigate whether physiological hyperinsulinemia has an influence on the access of macromolecules to insulin-sensitive tissues. To evaluate the effect of insulin on the perfusion of its own target regions a euglycemic hyperinsulinemic clamp study (insulin: 1.2 mU x kg-1 x min-1) was performed in 190 healthy volunteers (27.5 +/- years, BMI: 22.6 +/- 1.6 kg/m2) and compared to a saline control experiment. In a whole body approach we determined the kinetic of the extracellular marker inulin in serum and simultaneously in interstitial fluid of femoral skeletal muscle (FSM) and abdominal subcutaneous adipose tissue (SAT), applying the open-flow microperfusion technique (OFM). Serum and interstitial fluid inulin kinetics was comparable between the insulin and saline group showing a high reproducibility within groups. The appearance of inulin in interstitial fluid achieved a steady state after 75 min indicating total equilibration with serum, both comparable in FSM and SAT. Qualitative analysis of inulin kinetics was confirmed by model derived distribution and clearance parameters of inulin. Physiological hyperinsulinemia (insulin: 473 +/- 6 pM vs. saline: 102.5 +/- 5.7; NS) of no effect on distribution volume (insulin: 98.2 +/- 6.2 ml/kg vs. saline: 243.1 +/- 28.6; NS) or exchange parameter (insulin: 217.6 +/- 34.2 ml/min vs. saline: 243.1 +/- 28.6; NS) of inulin to peripheral insulin-sensitive tissue. Also all other parameters identified by the model were comparable between groups. Both model and measured data of inulin kinetics gibe first time evidence that FSM and SAT are slow equilibrating compartments for inulin. Furthermore the study shows that OFM allows stable sampling of macromolecules form the interstitial fluid of peripheral insulin-sensitive tissues. However, the present results indicate that in contrast to studies performed in dogs, insulin at physiological concentrations does not augment recruitment of insulin-sensitive tissues in healthy humans.