Influence of the metabolic environment on oxygen uptake and isometric developed tension of isolated rat portal vein.
Oxygen uptake and isometric developed tension (IDT) of isolated rat portal vein were simultaneously measured after glucose removal, following the readmission of metabolic substrates and addition of 2-deoxy-D-glucose (2-DG) or insulin. In control conditions, basal O2 uptake was 0.128 +/- 0.004 microliter O2/mg dry weight/min (n = 50). After 40 min of incubation in a glucose-free medium, IDT and O2 uptake decayed to a similar degree. Addition of 11 mM glucose, 5 mM pyruvate, acetate, lactate or butyrate to hypodynamic veins, elicited differential recoveries in the mechanical and metabolic parameters, pyruvate and acetate being the most effective. Insulin (0.1 U/ml) added 5 min prior to readmission of 11 mM glucose, increased the restoration of IDT without any effect on oxygen uptake. 2-DG 5.5 mM, when added in glucose-free medium, abolished IDT but only depressed the cellular respiration by 38% at 20 min; these effects were decreased in presence of glucose (11 mM). These results suggest that the oxygen uptake of this vessel depends, among other factors, on the exogenous substrate offered. They show also the relationship between peak of developed isometric force and metabolic activity as well as the relevance of glycolytic and oxidative pathways in this tissue.
D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000818:Animals; D050260:Carbohydrate Metabolism; D005950:Glucose Solution, Hypertonic; D066298:In Vitro Techniques; D007537:Isometric Contraction; D008297:Male; D009119:Muscle Contraction; D009131:Muscle, Smooth, Vascular / Q000378:metabolism*; D010101:Oxygen Consumption; D011169:Portal Vein / Q000378:metabolism; D011773:Pyruvates / Q000378:metabolism; D051381:Rats
D005950:Glucose Solution, Hypertonic; D011773:Pyruvates; D000251:Adenosine Triphosphatases