Role of adenosine transport in gestational diabetes-induced L-arginine transport and nitric oxide synthesis in human umbilical vein endothelium

J Physiol. 2004 Oct 1;560(Pt 1):111-22. doi: 10.1113/jphysiol.2004.068288. Epub 2004 Jul 22.


Gestational diabetes is associated with increased L-arginine transport and nitric oxide (NO) synthesis, and reduced adenosine transport in human umbilical vein endothelial cells (HUVEC). Adenosine increases endothelial L-arginine/NO pathway via A(2) purinoceptors in HUVEC from normal pregnancies. It is unknown whether the effect of gestational diabetes is associated with activation of these purinoceptors or altered expression of human cationic amino acid transporter 1 (hCAT-1) or human equilibrative nucleoside transporter 1 (hENT1), or endothelial NO synthase (eNOS) in HUVEC. Cells were isolated from normal or gestational diabetic pregnancies and cultured up to passage 2. Gestational diabetes increased hCAT-1 mRNA expression (2.4-fold) and activity, eNOS mRNA (2.3-fold), protein level (2.1-fold), and phosphorylation (3.8-fold), but reduced hENT1 mRNA expression (32%) and activity. Gestational diabetes increased extracellular adenosine (2.7 microM), and intracellular L-arginine (1.9 mM) and L-citrulline (0.7 mM) levels compared with normal cells (0.05 microM, 0.89 mM, 0.35 mM, respectively). Incubation of HUVEC from normal pregnancies with 1 microM nitrobenzylthioinosine (NBMPR) mimicked the effect of gestational diabetes, but NBMPR was ineffective in diabetic cells. Gestational diabetes and NBMPR effects involved eNOS, PKC and p42/44(mapk) activation, and were blocked by the A(2a) purinoceptor antagonist ZM-241385. Thus, gestational diabetes increases the L-arginine/NO pathway involving activation of mitogen-activated protein (MAP) kinases, protein kinase C (PKC) and NO cell signalling cascades following activation of A(2a) purinoceptors by extracellular adenosine. A functional relationship is proposed between adenosine transport and modulation of L-arginine transport and NO synthesis in HUVEC, which could be determinant in regulating vascular reactivity in diabetes mellitus.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine / metabolism*
  • Adult
  • Arginine / metabolism*
  • Cationic Amino Acid Transporter 1 / genetics
  • Cationic Amino Acid Transporter 1 / metabolism
  • Cells, Cultured
  • Citrulline / metabolism
  • Diabetes, Gestational / metabolism*
  • Endothelium, Vascular / cytology
  • Endothelium, Vascular / metabolism*
  • Female
  • Humans
  • Infant, Newborn
  • Mitogen-Activated Protein Kinase 1 / metabolism
  • Mitogen-Activated Protein Kinase 3 / metabolism
  • Nitric Oxide / metabolism*
  • Nitric Oxide Synthase / genetics
  • Nitric Oxide Synthase / metabolism
  • Nitric Oxide Synthase Type III
  • Pregnancy
  • Protein Kinase C / metabolism
  • RNA, Messenger / analysis
  • Receptor, Adenosine A2A / metabolism
  • Umbilical Veins / cytology


  • Cationic Amino Acid Transporter 1
  • RNA, Messenger
  • Receptor, Adenosine A2A
  • SLC7A1 protein, human
  • Citrulline
  • Nitric Oxide
  • Arginine
  • NOS3 protein, human
  • Nitric Oxide Synthase
  • Nitric Oxide Synthase Type III
  • Protein Kinase C
  • Mitogen-Activated Protein Kinase 1
  • Mitogen-Activated Protein Kinase 3
  • Adenosine