ISOLATED PERFUSED LIVER— BRAUER 



237 



LOG K' 



-LOG :— -0.2 



LOG ^ 

 D38 



-04 



-2.4 



CrP04 EXTRACTION 

 -LOGK'.|i 



BLOOD FLOW AT 12 5 CM 

 PERFUSION PRESSURE 



b ^t 



- LOG ;7- • -TV 

 bjB RT 



Ab* 6570 GAL 



Fig. 1. — Temperature coefficients of CrPO^ extraction (k' = reaction rate constant X active 

 surface concentration), blood flow rate at 12.5 cm. perfusion pressure, and bile secretion rate. 



whether these values reflect some peculiarity of the urethane anesthesia employed 

 by Dr. Kalow, or whether the discrepancy reflects real strain differences in the 

 temperature dependence of this function. 



Recovery of bile flow from hypothermia is usually prompt in livers cooled to 

 about 30° as well as those cooled to 17° C. At temperatures lying between these 

 limits, however, our experience has shown a relatively high proportion of failures 

 of bile flow to recover on rewarming. Since somewhat parallel observations were 

 made in connection with the colloid uptake studies, and perhaps may also underlie 

 the glucose picture, one might give thought to the possibility of a critical tempera- 

 ture range in which the rat liver may suffer most severely from cooling. In figure 2 

 it should also be noted that on rewarming after a period of hypothermia there is 

 a slight overshooting of bile flow rate, lasting perhaps 20 minutes before the new 

 plateau of bile flow is reached at a level close to that seen before cooling. 



During the periods of hypothermia bile composition does not appear greatly 

 changed. Bile solids remain constant, and our short series of chelate determina- 

 tions suggest no significant drop in the concentration of bile salts in bile. The 

 BSP data, to be discussed presently, also indicate normal concentrations of this dye 

 in bile. 



