The effect of reduction of perfusion rate on lactate and oxygen uptake, glucose output and energy supply in the isolated perfused liver of starved rats.
1. Lactate and O2 uptake and glucose output were studied in isolated livers from starved rats at perfusate flow rates varying from 100 to 7% of "normal" (11.25-0.75 ml/min per 100 g body wt.). 2. With moderate diminution of flow rate, lactate and oxygen uptake fell more slowly than would be expected if uptake purely depended on substrate supply. 3. Use of a mathematical model suggests that the intrinsic capacity of the liver for lactate uptake is unaffected until the flow rate falls below 25% of "normal". 4. Some lactate uptake was always observed even at 7% of the "normal" flow rate. 5. At flow rates below 33% of the "normal", lactate was increasingly metabolized by pathways other than gluconeogenesis, which became a progressively less important consumer of available O2. 6. ATP content decreased with diminution of flow rate, but substantially less markedly than did lactate uptake and glucose output. 7. Intracellular pH fell from a mean value of 7.25 at "normal" flow rate to 7.03 at 7% of the "normal" flow rate.
D000227:Adenine Nucleotides / Q000378:metabolism*; D000818:Animals; D001783:Blood Flow Velocity; D002245:Carbon Dioxide / Q000097:blood; D005943:Gluconeogenesis; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D007773:Lactates / Q000378:metabolism*; D008099:Liver / Q000378:metabolism*; D008102:Liver Circulation; D008297:Male; D008954:Models, Biological; D010101:Oxygen Consumption; D010477:Perfusion; D051381:Rats; D011919:Rats, Inbred Strains; D013217:Starvation / Q000378:metabolism
D000227:Adenine Nucleotides; D007773:Lactates; D002245:Carbon Dioxide