Increased capillary diffusion capacity for small ions in skeletal muscle in long-term diabetics.

Abstract

The disappearance rates of locally injected radioactive extracellular ions were studied in hyperemic human skeletal muscle (m. tibialis ant.) in 7 non-diabetics, 4 recently-diagnosed juvenile diabetics and 7 long-term juvenile diabetics with clinical manifestations of diabetic angiopathy. 24Na+ and 131I− were employed as tracers. The local blood flow was estimated by the 133Xenon clearance method.The capillary diffusion capacity, CDC, (Renkin's permeability-surface area product PS) was calculated in terms of the unidirectional flux of the tracers: CDC is the number of ml of interstitial fluid completely rinsed of tracer in the (imaginary) situation of infinitely high capillary blood flow, i.e. when no back-diffusion of tracer occurs.The average values for CDCNa and CDCI were found to be highly significantly increased (p<0.001) in the long-term diabetic group as compared to non-diabetics and recently-diagnosed diabetics: CDCNa=5.8; 4.2; 4.0 and CDCI=8.7; 6.4; 6.2 ml interstitial fluid per 100 g skeletal mu...