Changes of the respiratory coefficient in cultures of rat liver cells

The increase of oxygen consumption in liver cell cultures in medium 199 with addition of serum or of regenerative liver extract pleads for the existence of a factor stimulating energy-dependent processes (mitoses, protein synthesis), which is active both in vivo and in vitro. This stimulating factor is of liver origin, but with systemic offer. The concentration of the stimulating factor, which is the highest 3 days after operation, decreases as the normal liver cell population is re-established. The stimulating factor shows a limited specificity for tissues with epithelial structure and in vivo increased mitotic index the leukocytes being reactive only to very high concentrations of this factor. An optimal concentration of the stimulating factor exists which induces the more marked increase of oxygen consumption.