Abstract
Aims/hypothesis: We investigated the direct effect of a nitric oxide donor (spermine NONOate) on glucose transport in isolated human skeletal muscle and L6 skeletal muscle cells. We hypothesised that pharmacological treatment of human skeletal muscle with N-(2-aminoethyl)-N-(2-hydroxy-2-nitrosohydrazino)-1,2- ethylenediamine (spermine NONOate) would increase intracellular cyclic GMP (cGMP) levels and promote glucose transport. Methods: Skeletal muscle strips were prepared from vastus lateralis muscle biopsies obtained from seven healthy men. Muscle strips were incubated in the absence or presence of 5 mmol/l spermine NONOate or 120 nmol/l insulin. The L6 muscle cells were treated with spermine NONOate (20 μmol/l) and incubated in the absence or presence of insulin (120 nmol/l). The direct effect of spermine NONOate and insulin on glucose transport, cGMP levels and signal transduction was determined. Results: In human skeletal muscle, spermine NONOate increased glucose transport 2.4-fold (p∈<∈0.05), concomitant with increased cGMP levels (80-fold, p∈<∈0.001). Phosphorylation of components of the canonical insulin signalling cascade was unaltered by spermine NONOate exposure, implicating an insulin-independent signalling mechanism. Consistent with this, spermine NONOate increased AMP-activated protein kinase (AMPK)-α1-associated activity (1.7-fold, p∈<∈0.05). In L6 muscle cells, spermine NONOate increased glucose uptake (p∈<∈0.01) and glycogen synthesis (p∈<∈0.001), an effect that was in addition to that of insulin. Spermine NONOate also elicited a concomitant increase in AMPK and acetyl-CoA carboxylase phosphorylation. In the presence of the guanylate cyclase inhibitor LY-83583 (10 μmol/l), spermine NONOate had no effect on glycogen synthesis and AMPK-α1 phosphorylation. Conclusions/interpretation: Pharmacological treatment of skeletal muscle with spermine NONOate increases glucose transport via insulin-independent signalling pathways involving increased intracellular cGMP levels and AMPK-α1-associated activity.
Originalsprog | Engelsk |
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Tidsskrift | Diabetologia |
Vol/bind | 53 |
Udgave nummer | 6 |
Sider (fra-til) | 1142-50 |
Antal sider | 9 |
ISSN | 0012-186X |
DOI | |
Status | Udgivet - jun. 2010 |