Insulin and nitric oxide stimulates glucose transport in human placenta.
The present work examines whether insulin and NO can act as regulators of glucose transport in placenta. Glucose uptake (2-deoxy D-[(3)H]glucose) was measured in the absence (control or basal values) and in the presence of insulin (1200 microU/ml) or SNP (20 microM) in isolated perfused cotyledons and tissue slices preparations of human placenta. Both insulin and NO significantly increased glucose uptake by 20 and 27 per cent, respectively. Insulin decreased the Km of glucose transport from 42.5 +/- 2.69 to 35.1 +/- 2.58 mM. The stimulatory effect of SNP was mimicked by 8-CPT-cGMP and was completely blocked by the guanylate cyclase inhibitor, ODQ (10 microM). ODQ and the NOS inhibitor, L-NAME (100 microM), decreased basal glucose uptake but did not affect insulin-stimulated glucose transport. Taken together, these findings indicate that insulin and NO stimulate glucose uptake in human placenta and suggest that both potential regulators of glucose transport use different signaling pathways.
Acevedo
C Gloria
CG
Departamento de Fisiología, Facultad de Ciencias Biológicas, Universidad de Concepción, Casilla 160-C, Concepción, Chile. cacevedo@udec.cl
Márquez
J Luis
JL
Rojas
Susana
S
Bravo
Ivan
I
D001692:Biological Transport; D006152:Cyclic GMP / Q000031:analogs & derivatives* / Q000494:pharmacology; D017869:Cyclic GMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D016166:Free Radical Scavengers / Q000494:pharmacology*; D005947:Glucose / Q000378:metabolism*; D006162:Guanylate Cyclase / Q000037:antagonists & inhibitors; D006801:Humans; D007004:Hypoglycemic Agents / Q000494:pharmacology*; D007328:Insulin / Q000494:pharmacology*; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000494:pharmacology*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D010920:Placenta / Q000187:drug effects* / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects
C474799:CPT-cGMP; D004791:Enzyme Inhibitors; D016166:Free Radical Scavengers; D007004:Hypoglycemic Agents; D007328:Insulin; C016276:8-bromocyclic GMP; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D017869:Cyclic GMP-Dependent Protein Kinases; D006162:Guanylate Cyclase; D006152:Cyclic GMP; D005947:Glucose; D019331:NG-Nitroarginine Methyl Ester