Cyclic adenosine monophosphate-mediated protection against bile acid-induced apoptosis in cultured rat hepatocytes

Hepatology. 1998 May;27(5):1324-31. doi: 10.1002/hep.510270519.


Cyclic adenosine monophosphate (cAMP) has been shown to modulate apoptosis. To evaluate the role of cAMP in bile acid-induced hepatocyte apoptosis, we studied the effect of agents that increase cAMP on the induction of apoptosis by glycochenodeoxycholate (GCDC) in cultured rat hepatocytes. GCDC induced apoptosis in 26.5%+/-1.1% of hepatocytes within 2 hours. Twenty-minute pretreatment of hepatocytes with 100 micromol/L 8-(4-chlorothiophenyl) cAMP (CP-cAMP) resulted in a reduction in the amount of apoptosis to 35.2%+/-3.8% of that seen in hepatocytes treated with GCDC alone. Other agents that increase intracellular cAMP, including dibutyryl cAMP (100 micromol/L), glucagon (200 nmol/L), and a combination of forskolin (20 micromol/L) and 3-isobutyl-1-methylxanthine (20 micromol/L), also inhibited GCDC-induced apoptosis to a similar extent. Pretreatment with the protein kinase A (PKA) inhibitor, KT5720, prevented the protective effect of CP-cAMP and inhibited CP-cAMP-induced activation of PKA activity. Inhibitors of phosphatidylinositol 3-kinase (PI3K), wortmannin (50 nmol/L), or Ly 294002 (20 micromol/L) also prevented the cytoprotective effect of cAMP. PI3K assays confirmed that wortmannin (50 nmol/L) inhibited PI3K activity, while CP-cAMP had no effect on the activity of this lipid kinase. GCDC increased mitogen-activated protein kinase (MAPK) activity, but had no effect on stress-activated protein kinase (SAPK) activity in hepatocytes. cAMP decreased basal and GCDC-induced MAPK activity and increased SAPK activity. The MAPK kinase inhibitor, PD 98059, inhibited both GCDC-mediated MAPK activation and GCDC-induced apoptosis.

In conclusion: 1) agents that increase intracellular cAMP protect against hepatocyte apoptosis induced by hydrophobic bile acids; 2) activation of MAPK by GCDC may be involved in bile acid-induced apoptosis; and 3) cAMP-mediated cytoprotection against bile acid-induced apoptosis appears to involve PKA, MAPK, and PI3K.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Androstadienes / pharmacology
  • Animals
  • Apoptosis / drug effects*
  • Bile Acids and Salts / chemistry
  • Bile Acids and Salts / pharmacology*
  • Calcium-Calmodulin-Dependent Protein Kinases / antagonists & inhibitors
  • Calcium-Calmodulin-Dependent Protein Kinases / physiology
  • Carbazoles*
  • Cells, Cultured
  • Chromones / pharmacology
  • Cyclic AMP / physiology*
  • Cyclic AMP-Dependent Protein Kinases / physiology
  • Enzyme Inhibitors / pharmacology
  • Indoles / pharmacology
  • JNK Mitogen-Activated Protein Kinases
  • Liver / cytology*
  • Male
  • Mitogen-Activated Protein Kinases*
  • Morpholines / pharmacology
  • Phosphatidylinositol 3-Kinases / physiology
  • Phosphoinositide-3 Kinase Inhibitors
  • Pyrroles / pharmacology
  • Rats
  • Rats, Wistar
  • Signal Transduction
  • Solubility
  • Wortmannin


  • Androstadienes
  • Bile Acids and Salts
  • Carbazoles
  • Chromones
  • Enzyme Inhibitors
  • Indoles
  • Morpholines
  • Phosphoinositide-3 Kinase Inhibitors
  • Pyrroles
  • 2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one
  • KT 5720
  • Cyclic AMP
  • Cyclic AMP-Dependent Protein Kinases
  • Calcium-Calmodulin-Dependent Protein Kinases
  • JNK Mitogen-Activated Protein Kinases
  • Mitogen-Activated Protein Kinases
  • Wortmannin