[The effect of insulin on the changes in acid phosphatase activity and cAMP level in the primary monolayer culture of hepatocytes from newborn rats during anoxia]. / Vliianie insulina na izmenenie aktivnosti kisloi fosfatazy i urovnia tsAMF v pervichnoi monosloinoi kul'ture gepatotsitov novorozhdennykh krys v usloviiakh anoksii.

Effects of insulin was studied in the monolayer hepatocyte cultures of new born rats under anoxic conditions. Insulin 10(-7) M stabilized lysosomal membranes obtained after 20 min anoxia. I hr incubation of hepatocytes with insulin in normal conditions, which was followed by anoxia, caused a significant increase of acid phosphatase activity in the fraction enriched with lysosomes. Insulin caused more distinct stabilization effect on lysosomal membranes when its action was prolonged. On the other hand, insulin caused more than 2-fold increase of cAMP content in hepatocytes within 2 min of exposition as compared with control cultures. When exposition of the cells with insulin exceeded 2 min, lowering of cAMP content was observed. These data appear to indicate that stabilizing effect of insulin was secondary towards cAMP level increase. Indirect connection between cAMP level, insulin stabilizing action and the state of lysosomal membranes were noted in the rat hepatocyte culture.

[Primary culture of hepatocytes of newborn rats as a system for modeling anoxia and metabolic ischemia]. / Pervichnaia kul'tura gepatotsitov novorozhdennykh krys kak sistema dlia modelirovaniia anoksii i metabolicheskoi ishemii.

A primary culture of hepatocytes from new born rats was used as an experimental model suitable for studies of the cell lysosomal apparatus and of molecular mechanisms involving cyclic nucleotides for initiation of lysosomal response to extremal conditions. Substrate deficiency and anoxia of the cultivated hepatocytes were found to cause distinct alterations in the state of lysosomal apparatus accompanied by an increase in free activity of acid phosphatase.

[Changes in the cAMP levels and acid phosphatase activity in a monolayer primary culture of hepatocytes from newborn rats during anoxia and substrate deprivation]. / Izmenenie urovnia tsAMF i aktivnosti kisloi fosfatazy v monosloinoi pervichnoi kul'ture gepatotsitov novorozhdennykh krys v usloviiakh anoksii i substratnogo golodaniia.

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.