326 



E. LUNDSGAARD 



VOL. 4 (1950) 



TABLE I 



OXYGEN CONSUMPTION OF CAT LIVERS BEFORE, IO-I5 MINUTES AND 60 MINUTES AFTER CONNECTION 



WITH A "donor" ml/min 



As the high rate of oxygen consumption in the liver after connection with the donor 

 is maintained or even increases slightly during the entire experimental period though 

 the liver is still artificially perfused the possibility that the decline in oxygen uptake 

 might be a direct consequence of the artificial perfusion is ruled out. The conditions 

 before and after connection with the donor differ in only one respect. Before the connec- 

 tion when the blood is oxygenated in the oxygenator the oxygen tension is higher in 

 the blood entering the liver than after the connection when the blood is oxygenated in 

 the lungs of the donor. Though it is most improbable that the oxygen tension of the 

 blood entering the liver is of any significance a few experiments have been carried out 

 in which the perfusion blood was oxygenated with alveolar air collected in a Douglas 

 bag instead of the ordinary mixture of oxygen and 4% carbon dioxide. The oxygen 

 uptake of the liver in these experiments showed exactly the same variations as in experi- 

 ments carried out with the usual technique. 



The glucose output from an isolated cat liver averages about 2 mg per minute. 

 The glucose output from a liver after connection with a donor averages about 9 mg per 

 minute. The extra amount of glucose given off by a liver after connection with a donor 

 undoubtedly originates from lactic acid. 



In ordinary perfusion experiments on cat livers the lactic acid concentration 

 rapidly falls to very low levels (3 to 5 mg%). In experiments in which the artificially 

 perfused liver is connected with a donor the lactic acid concentration in the blood with 

 which the liver is supplied is as high as 30 to 50 mg%. A definite drop in lactic acid 

 concentration from ingoing to outgoing blood corresponding roughly to the increase in 

 glucose concentration is demonstrable. 



As the lactic acid concentration declines during the first period of a liver perfusion 

 experiment during which the oxygen uptake falls off also and as the lactic acid concen- 

 tration is markedly increased after connection with a donor when the oxygen consump- 

 tion increases strongly one might think that the concentration of lactic acid in the blood 

 is responsible for the changes in the oxygen uptake of the liver. Observations have 

 previously been mentioned however which do not agree with such an assumption. 

 Furthermore a number of experiments have been carried out in which l ( + ) lactic acid 

 was added to the perfusion blood. If at the start of the perfusion l ( + ) lactic acid is 

 added to the blood in amounts increasing the concentration to well above 100 mg% 

 the decline in oxygen uptake proceeds as usual and if lactic acid in varying amounts is 

 References p. 329. 



