Effects of anisotonic exposure on duck hepatitis B virus replication

• Published in: Hepatology (Baltimore, Md.) Md.), 1994-07, Vol.20 (1), p.1-7
• Main Authors: Offensperger, Wolf‐Bernhard, Offensperger, Silke, Stoll, Barbara, Gerok, Wolfgang, Häussinger, Dieter
• Format: Article
• Language: English
• Subjects: Animals; Biological and medical sciences; Blotting, Western; Cell Size - drug effects; Cells, Cultured; Culture Media; DNA Replication - drug effects; DNA, Viral - biosynthesis; Ducks; Gastroenterology. Liver. Pancreas. Abdomen; Hepatitis B Virus, Duck - drug effects; Hepatitis B Virus, Duck - genetics; Hepatitis B Virus, Duck - physiology; Liver - microbiology; Liver - pathology; Liver. Biliary tract. Portal circulation. Exocrine pancreas; Medical sciences; Osmolar Concentration; Other diseases. Semiology; RNA, Viral - biosynthesis; Sodium Chloride - pharmacology; Transcription, Genetic - drug effects; Viral Proteins - biosynthesis; Virus Replication - drug effects
• ISSN: 0270-9139; 1527-3350
• DOI: 10.1002/hep.1840200102

In cultured hepatocytes from in vivo duck hepatitis B virus‐infected ducks the effect of medium osmolarity on viral replication was studied. A 10‐day exposure to hypotonic media (277 mOsm/L due to removal of 26 mmol/L NaCl) lowered the duck hepatitis B virus DNA content of cells and of the medium by about 50%, whereas hyperosmotic exposure (421 mOsm/L by addition of 46 mmol/L NaCl) increased it about four‐fold compared with normotonic standard incubation medium (329 mOsm/L). The tissue levels of viral RNA transcripts increased during the 10 days of hypertonic exposure but decreased only slightly after hypoosmotic treatment. Western‐blot analysis for the production of viral pre‐S/S proteins revealed a marked stimulation of viral protein synthesis in hypertonic media, whereas hypotonic exposure inhibited it. Conversely, total cellular protein synthesis as assessed from [3H]leucine incorporation into acid‐precipitable material decreased during hyperosmotic exposure but increased during hypoosmotic exposure. We noted a comparable increase of duck hepatitis B virus DNA when raffinose (80 mmol/L) was added to hypotonic or normotonic media, without change in the NaCl concentrations. This suggests that the effects of anisotonicity on viral replication were not due to alterations of Na+ or Cl− activity in the incubation media, but might reflect changes of cellular volume. The effects of anisotonicity on viral replication were only seen after exposure of more than 8 hr of the cells to anisotonicity. The findings suggest that the cellular volume is an important determinant for duck hepatitis B virus replication, yet the underlying molecular mechanisms remain elusive. (Hepatology 1994;20:1–7.)