Tadalafil increases muscle capillary recruitment and forearm glucose uptake in women with type 2 diabetes

• Aims/hypothesis Recent evidence suggests that reduced synthesis of nitric oxide in endothelial cells, i.e. endothelial dysfunction, contributes to the impaired action of insulin in the vasculature of patients with type 2 diabetes. We investigated whether selective inhibition of phosphodiesterase-5 by tadalafil has beneficial effects on peripheral microcirculation and glucose uptake in these patients. Methods We enrolled seven postmenopausal women with type 2 diabetes and ten age-matched healthy women as controls in a placebo-controlled study to evaluate the acute metabolic effects of tadalafil. We performed microdialysis and blood flow measurements in muscle, and sampled arterial and deep venous blood before and after a single dose of tadalafil 20 mg or placebo. Circulating glucose and insulin levels, muscle capillary recruitment as reflected by permeability surface area for glucose (PSglu) and forearm glucose uptake were measured. Results In women with type 2 diabetes, but not in the control group, tadalafil induced increases in the incremental AUC for PSglu (tadalafil vs placebo 41±11 vs 4±2 ml [100 g]−1 min−1, p<0.05) and forearm glucose uptake (46±9 vs 8±4 µmol [100 g]−1 min−1, p<0.05). The variable that best predicted forearm glucose uptake was PSglu, which explained 70% of its variance. However, fasting glucose and insulin concentrations were similar following treatment with placebo or tadalafil in the two groups. Conclusions/interpretation This study suggests that tadalafil evokes positive metabolic effects in insulin-resistant women with type 2 diabetes.

Nyckelord

physiological hyperinsulinemia

metabolic syndrome

insulin action

risk

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