Plasma-kallikrein clearance during liver regeneration after partial hepatectomy in the rat.
OBJECTIVE
The liver clears circulating plasma-kallikrein through a receptor-mediated endocytosis process: an initial fast phase is followed by a slow exponential phase.


METHODS
To determine whether the clearance rate of plasma-kallikrein is affected during liver regeneration, we perfused isolated rat livers with rat plasma-kallikrein (rPK) at 0, 1, 2, 3 and 7 days after partial hepatectomy or sham operation.


RESULTS
Liver regeneration was followed by the expression of the proliferating-cell nuclear antigen (PCNA) labeling index. The serum concentration of alpha2-macroglobulin, an acute phase protein in rats, was measured. At day 1, the fast phase of rPK clearance rate increased in hepatectomized rats when compared with day 0 (4.9+/-0.4 and 3.7+/-0.4 mU/g liver min, p<0.05). However, at day 2, the rPK fast phase clearance rate dropped significantly (2.6+/-0.2, p<0.05), when compared with day 1. No difference was found among the sham groups at different days of hepatectomy. These changes seem to be independent of the acute phase reaction. The regenerative liver weight increased continuously during the observation period. PCNA expression increased significantly after hepatectomy, with maximal PCNA-labeling indices at days 1 and 2, declining thereafter.


CONCLUSIONS
The rPK fast phase clearance rate changes during liver regeneration, with a zenith occurring when PCNA labeling index is maximal (day 1) and a nadir occurring at the mitotic phase (day 2).
Braulio
V B
VB
Department of Medicine, Hospital Universitário Clementino Fraga Filho, Universidade Federal do Rio de Janeiro, Brazil.
Kouyoumdjian
M
M
Zucoloto
S
S
Figueiredo
F
F
Borges
D R
DR
D000818:Animals; D006498:Hepatectomy; D007610:Kallikreins / Q000008:administration & dosage / Q000493:pharmacokinetics*; D008099:Liver / Q000378:metabolism*; D008115:Liver Regeneration / Q000502:physiology*; D008297:Male; D008657:Metabolic Clearance Rate; D009929:Organ Size; D010477:Perfusion; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D000511:alpha-Macroglobulins / Q000032:analysis
D018809:Proliferating Cell Nuclear Antigen; D000511:alpha-Macroglobulins; D007610:Kallikreins