Growing and expanding primary, differentiated adult cells in culture is difficult and laborious because many differentiated cells can only be maintained in vitro for a limited period of time. However, for controlled experiments, it may be necessary to maintain a consistent population of cells.Maintaining a population of adult stem cells （ASCs）, allows one to exponentially propagate a population of cells in vitro, and induce differentiation when desired. This is possible with SACK cell strains and specified cell culture conditions.SACK ASC cell properties – Long-term propagation in xanthosine （Xs）-supplemented mediumSuppressed asymmetric cell kineticsDifferentiated progeny cell properties – Xs-free medium supplemented with 10％ rat serum, confluent monolayer; or serum reduction and Xs-free medium supplemented with 10％ bovine serumBiliary PropertiesAlbumin expression, but no secretionAlpha-fetoprotein secretionCK7 expression （biliary epithelial cell marker） Form tubules with polarized cells （e.g., luminal microvilli）
