HEPATOCYTE CULTURE UTILIZING POROUS POLYVINYL FORMAL RESIN MAINTAINS LONG-TERM STABLE ALBUMIN SECRETION ACTIVITY

To investigate the effects of culture conditions on the maintenance of metabolic functions of cultured hepatocytes, long-term hepatocyte cul ture lasting 20 days was performed under two different culture conditi ons, i.e. stationary cultures utilizing porous polymer (polyvinyl form al (PVF) resin) as a substratum and conventional monolayer dish cultur es without PVF. Metabolic activities specific to hepatocytes were eval uated in terms of ammonia metabolism, urea synthesis, and albumin secr etion. Concerning ammonia metabolic and urea synthetic activities, no significant differences in maintenance of these activities were found between the two culture conditions, and these activities rapidly decre ased with the elapse of the culture period, especially during the earl y stage of the experiments. However, after day 10, these activities in the stationary cultures were maintained al a slightly more favorable level than in the monolayer cultures. On the other hand, compared with ammonia metabolism and urea synthesis, stable and well-maintained alb umin secretion of hepatocytes (60% of the activity in day 1) was exhib ited in the stationary culture experiments, despite that this particul ar activity under the monolayer culture condition gradually reduced to a very low level (5.7% of that on day 1) at the end of the culture. F rom the morphological observations, hepatocytes immobilized in the PVF resin revealed individual spherical shapes without forming multicellu lar aggregation, and it was suggested that this characteristic structu re contributed to good albumin secretion of hepatocytes. In conclusion , the advantages of the hepatocyte culture technique utilizing PVF res in over the conventional dish culture in maintaining some representati ve metabolic function specific to hepatocytes were clarified.