Effects of glucagon-like peptide 1(9-36) on endothelial nitric oxide synthase in human umbilical vein endothelial cells

Abstract

To explore the effects of glucagon-like peptide 1 (GLP-1(9-36)) on endothelial nitric oxide synthase (eNOS) in human umbilical vein endothelial cells (HUVEC). HUVEC cultured under the conditions of normal glucose (5.5 mmol/L) or high glucose (16.8 mmol/L) were incubated with 5-5000 pmol/L GLP-1(9-36). NO production was assayed by the nitrate reductase method. The eNOS activities were detected by NOS assay kit, p-eNOS (ser-1177) level and total eNOS protein level by Western blot and eNOS mRNA level by real-time reverse transcription-polymerase chain reaction (RT-PCR). Under normal glucose condition, NO productions from HUVEC of 50 - 5000 pmol/L GLP-1(9-36) groups were significantly higher than the control ((41.6 ± 8.1) µmol/L vs (22.2 ± 2.6) µmol/L, P < 0.05). So were eNOS activities in cells (1.76 ± 0.12 vs 1.00 ± 0.00, P < 0.05). Compared with the control group, the levels of eNOS phosphorylation at ser-1177, mRNA and total protein were significantly elevated in the 5000 pmol/L GLP-1(9-36) group. Under high glucose condition, GLP-1(9-36) retained all the above effects. GLP-1 (9-36) can increase NO release, eNOS activity and expression in HUVEC. This may be one of the underlying mechanisms for the protective effects of GLP-1(9-36) on cardiovascular system.