Diminished insulin-mediated forearm blood flow and muscle glucose uptake in young men with low birth weight

Background: Low birth weight (LBW) is associated with increased risk of type 2 diabetes and cardiovascular disease. We studied endothelial function and insulin sensitivity in young men with LBW (n = 22) and controls (n = 22). Methods: Insulin sensitivity and endothelial function was studied with venous occlusion plethysmography and intra-arterial infusions of adenosine and acetylcholine, before and during a hyperinsulinemic isoglycemic clamp. Results: Forearm blood flow response to systemic hyperinsulinemia was diminished in LBW compared to controls (p < 0.05). Fractional arteriovenous glucose extraction was similar, and consequently insulin-stimulated forearm glucose clearance was diminished in LBW compared with controls (0.8 ± 0.09 vs. 1.4 ± 0.36 ml·100 ml–1·min–1, respectively, p < 0.05). Forearm blood flow response to adenosine and acetylcholine with or without insulin stimulation did not differ between groups. Whole-body glucose uptake was lower in LBW than controls (8.7 ± 0.5 and 9.1 ± 0.6 mg·min–1·kg–1 lean body mass); however, this was not significant. Conclusions: Forearm blood flow response to insulin is impaired in LBW, whereas the response to adenosine and acetylcholine is preserved. The impaired insulin-mediated increase in bulk flow in LBW may be due to an impairment of insulin-mediated capillary recruitment independent of – or preceding – whole-body insulin resistance in LBW subjects.