THE INFLUENCE OF MEDIUM COMPOSITION ON THE MAINTENANCE OF CYTOCHROME-P-450, GLUTATHIONE CONTENT AND UREA SYNTHESIS - A COMPARISON OF RAT AND SHEEP PRIMARY HEPATOCYTE CULTURES

Rat and sheep primary hepatocytes have been cultured in four different medium formulations: Williams' E, Chee's, Medium 199 and Modified Ear le's, The total cytochrome P450 content, intracellular concentration o f reduced glutathione, rate of urea synthesis and total protein conten t of cultures of cells from both species in each medium have been dete rmined. Modified Earle's and Chee's medium proved to be the most favou rable formulations for the culture of rat hepatocytes, After 48 h, cel ls cultured in Modified Earle's had significantly more cytochrome P450 and a significantly greater rate of urea synthesis than cells in any other medium, After 6 days in culture the difference in cytochrome P45 0 levels between rat hepatocytes in Chee's medium and those in Modifie d Earle's medium was abrogated, The difference in the rate of urea syn thesis between rat hepatocytes cultured in each of these two media was shown to be more dependent on the medium in which the cells were main tained during the period of urea synthesis measurement than on the med ium in which the cells had been previously cultured, Sheep hepatocytes cultured in Chee's medium ruptured and died within 24 h, Apart from t his, sheep cells were less sensitive to changes in medium formulation than were rat hepatocytes, The initial plating efficiency was lower in sheep cells, Total cytochrome P450 content was the most discriminator y of the four parameters for evaluating the status of rat hepatocyte c ultures. However, urea synthesis may be the most useful parameter for assessment of hepatocyte function in hybrid liver devices such as bioa rtificial liver support systems where access to the cells during opera tion of the device is restricted. (C) Journal of Hepatology.