Characterization of the asialoglycoprotein receptor under hypoxic conditions in primary cultured rat hepatocytes.
Hepatic ischemia/reperfusion injury occurs in numerous clinical situations including liver transplantation and hepatic resection. Therefore, accurate functional assessment of hepatocytes and prevention of ischemia/reperfusion injury to hepatocytes would be important. (99m)Tc-Galactosyl-human serum albumin is a liver scintigraphic agent that binds to asialoglycoprotein receptors (ASGP-R) on hepatocytes. We determined the number of ASGP-R during hypoxic conditions in primary cultured rat hepatocytes.


METHODS
We used 3 durations of hypoxia (1, 2, and 3 h) for the cultured rat hepatocytes. The control incubation was performed under normoxic conditions (humidified 5% CO(2) in air) for the entire experiment. The maximal binding of (99m)Tc-galactosyl-human serum albumin (Bmax) to the hepatocytes (plasma membrane and endocytosis) and ketone body ratio (KBR) in the medium were estimated.


RESULTS
The Bmax to hepatocytes and the KBR significantly decreased with time under the 3 different hypoxic conditions, whereas the cell counts of the hepatocytes did not decrease. Three hours after reoxygenation, the Bmax and KBR values that were decreased in the first 2 h of hypoxia reversed to control levels, but those Bmax and KBR values that were decreased after 3 h of hypoxia were irreversible.


CONCLUSIONS
We conclude that the decrease in the number of ASGP-R per hepatocyte appears to be more significant than the decrease in the number of hepatocytes. Therefore, measurement of ASGP-R may provide an accurate assessment of hepatic function in the clinical setting of hepatic injury and recovery.
Kwon
A-Hon
AH
Department of Surgery, Kansai Medical University, Osaka 570-8507, Japan. kon@takii.kmu.ac.jp
Inoue
Tomohisa
T
Ha-Kawa
Sang Kil
SK
D000818:Animals; D037263:Asialoglycoprotein Receptor / Q000378:metabolism*; D015687:Cell Hypoxia / Q000502:physiology*; D002478:Cells, Cultured; D004705:Endocytosis / Q000502:physiology*; D022781:Hepatocytes / Q000000981:diagnostic imaging* / Q000378:metabolism*; D008297:Male; D008657:Metabolic Clearance Rate; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D051381:Rats; D017208:Rats, Wistar; D013668:Technetium Tc 99m Aggregated Albumin / Q000493:pharmacokinetics*; D016284:Technetium Tc 99m Pentetate / Q000493:pharmacokinetics*
D037263:Asialoglycoprotein Receptor; D019275:Radiopharmaceuticals; D013668:Technetium Tc 99m Aggregated Albumin; C070561:technetium Tc 99m DTPA-galactosyl-human serum albumin; D016284:Technetium Tc 99m Pentetate