Maintenance of microsomal cytochromes b5 and P-450 in primary cultures of parenchymal liver cells on collagen membranes

In previous reports from various laboratories, the levels of the microsomal cytochromes b₅ and P-450 in hepatocytes in primary culture have been found to be very low and difficult to measure. The studies reported in this paper demonstrate that cytochromes b₅ and P-450 in hepatocytes cultured on floating collagen membranes for periods of at least 10 days are maintained at levels readily measured by conventional techniques and comparable to those of liver $\text{in}$$\text{vivo}$. Addition of high levels of hydrocortisone (10^?4M) to the culture medium for periods up to 10 days resulted in further increases in the levels of these cytochromes. Cells cultured in the presence of hydrocortisone exhibited the appearance of cytochrome P-448, in contrast to the cells cultured in the absence of hydrocortisone, where cytochrome P-450 was maintained.