Oxygen debt: Involvement of the Cori cycle

Abstract

Tryptophan and quinolinic acid, inhibitors of gluconeogenesis, were used to block the removal of lactate by the liver in order to investigate the involvement of the Cori cycle in oxygen debt. Five male, mongrel dogs were run on a treadmill at 4 mph with a 20 percent grade for 19 min. The mean exercise was 80.67±3.11 ml/kg/min for the control tests while peak arterial lactate values ranged from 3.83 to 4.98 mM/l. When removal of lactate by the liver was blocked, oxygen debt showed a mean reduction of 44 percent. Moreover, oxygen consumption during the last minute of exercise was reduced by 11 percent.