CHANGES IN MITOCHONDRIAL RHODAMINE-123-FLUORESCENCE POPULATIONS OF RAT HEPATOCYTES IN PRIMARY CULTURE

Flow cytometry analysis of mitochondria isolated from rat hepatocytes at different stages of development revealed two different rhodamine-123-stained fluorescence populations distinguishable by their main fluorescence channel. The high-fluorescence population (HFP) was minor, accounting for about 32, 33, and 23% of the total mitochondrial fraction in hepatocytes from preterm, term, and early (1 h) newborn rats, respectively. The percentage of HFP decreased during the first 20 h of hepatocytes in culture from preterm and term fetuses but not those from early newborns, in which the decrease occurred during the second day of culture. However, after 20 h in culture more than 80% of hepatocytes reached the G0/G1 phase, whatever the stage of development in which they were sown. This suggests that the observed changes in the fluorescence populations are not associated with the cell cycle; instead these changes mimic those observed during postnatal development and are therefore presumably due to mitochondrial differentiation. © 1993 Academic Press, Inc.