VOL. 4 (1950) METABOLIC RATE OF THE LIVER 325 



the blood at the start of the experiment (oxygen uptake 4.08 ml/min) was 20 mg%, at 

 the maximum of the first response (oxygen uptake 3.30 ml/min) 7 mg% and at the 

 maximum of the second response (oxygen uptake 3.25 ml/min) 26 mg%. 



These observations on the rate of oxygen consumption in the isolated liver would 

 probably not have been published if the effect of the periphery on the metaboHc rate of 

 the liver had not been revealed in a much more striking manner in some other experi- 

 ments performed for quite a different purpose. 



A cat was hepatectomized by connecting the protal vein with the right renal vein 

 through a cannula of suitable shape and ligating the hepatic vessels. Heparin had been 

 injected to prevent clotting. The blood sugar concentration of the animal was kept as 

 constant as possible by continuous intravenous injection of glucose. In some experi- 

 ments in which the hepatectomy was not successful the cat was eviscerated. No dif- 

 ference has been observed in the results obtained in experiments on hepatectomized 

 and eviscerated animals. As soon as the operation was finished a cat liver was isolated 

 and run with artificial perfusion for 35 to 50 minutes. After this period of time, the oxygen 

 uptake of the liver has fallen to a constant low level. The glucose concentration in the 

 perfusion blood was followed. From these determinations the glucose output of the iso- 

 lated liver can be computed with fair accuracy as the blood volume is known. 35 to 50 

 minutes after the start of the artificial perfusion the oxygen uptake of the liver was 

 determined by means of the Van Slyke technique. 



The isolated liver was then connected with the hepatectomized cat in the following 

 way. The venous outflow from the liver was connected with the jugular vein of the he- 

 patectomized cat which henceforward shall be denoted the "donor". From the carotic 

 artery of the donor, blood was allowed to run into a 100 ml cylinder containing about 

 50 ml of blood. Simultaneously the pump was shifted from the blood reservoir connected 

 with the oxygenator to the 100 ml cylinder cutting out the oxygenator and reservoir 

 from the circuit. The blood which flowed from the donor into the cylinder was then taken 

 up by the pump and sent through the liver at a constant rate determined by the pump. 

 From the liver the blood returned to the donor. By means of a clamp on the outflow 

 from the carotic artery of the donor it was fairly easy to manage to keep the blood volume 

 in the cylinder constant, z.^., to secure that the amount of blood leaving equalled the 

 amount of blood entering the donor. 



When the liver was connected with the donor the glucose infusion was stopped. 

 At suitable intervals samples were drawn simultaneously from the blood entering and 

 leaving the liver. Oxygen, carbon dioxide, glucose, and lactic acid determinations have 

 been performed on these samples. Oxygen and carbon dioxide were determined with 

 the Van Slyke technique, glucose according to Hagedorn- Jensen, and lactic acid 

 according to Barker and Summerson modified by LePage. 



The results related to our problem are presented in Table L It is seen that within 

 10 minutes after the connection of the liver with the donor the rate of oxygen consump- 

 tion in the liver has increased 100% or even more. One hour after the connection the 

 oxygen uptake of the liver in most experiments shows a slight further increase. In other 

 words the connection with a donor of a liver run with artificial perfusion until the oxygen 

 uptake has dropped to a low level increases the rate of oxygen uptake to a rate similar 

 to that observed immediately after isolation of the liver, i.e., presumably to the normal 

 rate. It may be mentioned that this very considerable change in rate of oxidations is 

 not accompanied by any change in the respiratory quotient. 

 References p. 32g. 



