Intracellular trafficking during liver regeneration. Alterations in late endocytic and transcytotic pathways.
OBJECTIVE
Liver growth, induced by partial hepatectomy of the organ is a precisely regulated process during which a radical reorganisation of metabolism occurs as the hepatocytes become committed to enter the cell cycle. Recent studies have shown the importance of the endocytic compartment in the control of lipid and protein intracellular trafficking but also in the control of the signal transduction events, which eventually will trigger the initiation of DNA synthesis and the subsequent cell division.


METHODS
We isolated endosomes at different times after partial hepatectomy in male rats and compared with endosomes isolated from sham-operated animals. Also, bile was collected and analysed by 2D-gel electrophoresis.


RESULTS
The amount of late endosomes isolated from regenerating livers decreased, concomitant with decreased cathepsin D specific enzyme activity. Furthermore, secretion of horseradish peroxidase, pIgA and transferrin increased in the pre-replicative phase of liver regeneration.


CONCLUSIONS
At the early stages of liver regeneration, the hepatocellular transport pathway towards degradation (late endosomes and lysosomal pathway) decreases, but the transcytosis and the bile secretion of several major proteins increases.
Fernández
Manuel A
MA
Departament de Biologia Cellular, Institut d'Investigacions Biomèdiques August Pi i Sunyer, Facultat de Medicina, Universitat de Barcelona, Casanova 143, 08036 Barcelona, Spain.
Turró
Silvia
S
Ingelmo-Torres
Mercedes
M
Enrich
Carlos
C
Pol
Albert
A
D000818:Animals; D001646:Bile / Q000378:metabolism*; D001692:Biological Transport; D001769:Blood / Q000378:metabolism*; D002402:Cathepsin D / Q000378:metabolism; D015180:Electrophoresis, Gel, Two-Dimensional; D004705:Endocytosis; D011992:Endosomes / Q000378:metabolism*; D006498:Hepatectomy / Q000379:methods; D006735:Horseradish Peroxidase / Q000493:pharmacokinetics; D007425:Intracellular Membranes / Q000378:metabolism*; D008115:Liver Regeneration / Q000502:physiology*; D008297:Male; D011184:Postoperative Period; D021381:Protein Transport; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors
D006735:Horseradish Peroxidase; D002402:Cathepsin D