Background Impaired vasodilatation in skeletal muscle is a possible mechanism linking insulin resistance to blood pressure regulation. Increased renal vascular resistance has been demonstrated in the offspring of essential hypertensives. We assessed whether insulin-mediated renal vasodilatation is impaired in insulin-resistant normal subjects.
Design In two groups of 10 insulin-resistant and 10 insulin-sensitive normal subjects, we compared the effects of sequential physiological and supraphysiological insulin dosages (50 and 150 mU kg(-1) h(-1)) on renal plasma flow (RPF) and leg blood flow using the euglycaemic clamp technique, I-131-labelled Hippuran clearances and venous occlusion plethysmography. Time-control experiments were performed in the same subjects.
Results Whole-body glucose uptake amounted to 4.9 +/- 2.1 and 11.0 +/- 2.4 mg kg (-1)min(-1) in the insulin-resistant and to 12.7 +/- 2.3 and 17.4 +/- 2.6 mg kg (-1)min(-1) in the insulin-sensitive subjects during physiological and supraphysiological hyperinsulinaemia, respectively. RPF increased more in insulin-sensitive compared to insulin-resistant subjects during physiological hyperinsulinaemia (13.7 vs. 6.8%, P <0.05). RPF increased to comparable levels during supraphysiological hyperinsulinaemia. Insulin-mediated changes in leg blood flow did not differ between groups. In the combined group, we found a positive correlation between insulin-mediated glucose uptake and changes in RPF during physiological hyperinsulinaemia (r = 0.57, P = 0.009), whereas insulin-mediated glucose uptake correlated with changes in leg blood flow during supraphysiological hyperinsulinaemia (r = 0.54. P = 0.017).
Conclusions Our results suggest that the sensitivities of the skeletal muscle and renal vascular bed differ for insulin's vasodilatory action. Insulin-mediated increases in RPF are impaired in insulin-resistant but otherwise normal subjects during physiological hyperinsulinaemia.
|Number of pages||9|
|Journal||European Journal of Clinical Investigation|
|Publication status||Published - Dec-2000|
- blood pressure
- insulin resistance
- leg blood flow
- renal plasma flow
- MUSCLE BLOOD-FLOW
- HYPERINSULINEMIA-INDUCED HYPERTENSION
- GLOMERULAR-FILTRATION RATE
- NORMOTENSIVE SUBJECTS
- EXOGENOUS INSULIN
- SODIUM RETENTION
- FAMILY HISTORY