TECHNIQUES FOR MEASUREMENT OF OXYGEN-CONSUMPTION RATES OF HEPATOCYTESDURING ATTACHMENT AND POST-ATTACHMENT

Three techniques for measuring oxygen consumption rate (OCR) of cultur ed cells relevant to the development of bioartificial liver devices ar e reported. In an oxystat apparatus, HepG2 cells immobilised on Cytode x 3 microcarriers at a concentration of 10(6) cells ml(-1) had a mean OCR of 0.7 nmol s(-1)/10(6) cells. The OCR decreased with increasing c ell density, a characteristic previously reported for other cell lines . Rat hepatocytes immobilised on single collagen layers in a flow cell and challenged with ammonia had a mean OCR of 0.59 nmol s(-1)/10(6) c ells. A novel two-compartment oxystat system was used to determine the OCR of rat hepatocytes during the attachment phase. OCR declined from 1.0 nmol S-1/10(6) immediately after seeding to 0.7 nmol s(-1)/10(6) cells at nine hours. The low OCR for HepG2 reflects loss of certain ox ygen dependent metabolic pathways. The OCR measured for rat hepatocyte s during and post-attachment are significantly higher than those repor ted elsewhere and have major implications for the development of bioar tificial liver devices.