Changes in the cAMP levels and acid phosphatase activity in a monolayer primary culture of hepatocytes from newborn rats during anoxia and substrate deprivation

: Acid phosphatase activity and cAMP level were studied in primary hepatocyte culture of new born rats under conditions of anoxia and substrate deprivation (incubation of the cells in Hanks salt solution). Incubation of hepatocytes in Hanks salt solution within one hour under conditions of anoxia caused a significant increase in free (cytosolic) enzyme activity. Substitution of Hanks salt solution by normal tissue culture medium and reoxygenation after 1 hr anoxia resulted in a decrease of free acid phosphatase activity, whereas activity of the enzyme in lysosomal fraction was increased. Content of cAMP was decreased distinctly after 15 min incubation of hepatocyte culture under conditions of anoxia and substrate deprivation and was increased above control values within 5 min of reoxygenation and substitution of Hanks salt solution by normal tissue culture media. Addition of cAMP-containing liposomes to hepatocyte culture under these experimental conditions led to a decrease in free acid phosphatase activity and to an increase of the enzyme activity in lysosomal fraction. cAMP appears to modulate the lability of hepatocyte lysosomal membrane. The mechanisms involved in these processes are discussed.