Glucose uptake orthophosphate exchange lactate and pyruvaterelease of perfused rat hind-limb during phosphorus deficiency

RESUMO

This experimental work was carried out on perfused skinned hind-limbs from three groups of rats fed-ad-libitum (FAL), phosphorus deficient (PD) and pair-weighed (PW), all of them fasted for 24 hours before the experiments. The perfusate was prepared using KRB solution to which was added bovine albumin (3 g.%), glucose (180 mg/dl), orthophosphate (0.5 mg/dl) and approximately 16-18 per cent of fresh washed rats erythrocytes. pH was adjusted to 7.40. The medium was bubbled with hunid O2-CO2 gas mixture (95/5%). Initial perfusate volume was 90 ml. 32Pi (0.5*Ci/ml) was incorporated to the medium at -15 minutes time.Parameters measured were perfusate glucose, perfusate plasma Pi, perfusate 32Pi, perfusate plasma Pi relative specific activity, perfusate lactate and perfusate pyruvate. Samples were obtained every 15 minutes up to 90 minutes. Insulin (200 *U/ml) was added to perfusate as a bolus at 0 minutes time, in the experiments in which the effect to the hormone was appraised. The spontaneous glucose uptake was greater in the PD group than in the FAL group, but no significant difference was found between PD and PW. Insulin increased the glicose uptake in the three groups, but the difference between PD and the other two groups was not significant. The perfusate plasma Pi rose gradually in all groups. In the stage 0-30 minutes hypophosphatemia was still present, and the increase in glucose uptake determined by insulin was not significantly different from the spontaneous incorporation of the hexose to the preparations in the PD group. The spontaneous Pi release to the medium by the preparations was not significantly differ..