[Biosynthesis of two molecular forms of ceruloplasmin in rat liver and their polar secretion into the blood stream and bile].
Biosynthesis and secretion of ceruloplasmin (CP) in rat liver has been studied in order to elucidate its role in the distribution, transport and excretion of copper in the body. The kinetics and topography of CP synthesis, intracellular transport and secretion were followed using in vivo pulse-chase experiments. It was found that the newly formed CP was firmly bound to endoplasmic reticulum membranes in the hepatocytes. Liver slices incubated in vitro with [35S]methionine were characterized by a two-stage release of [35S]CP into the medium. After 30-min incubation the medium contained 200 kDa CP-like protein, while after 120 min the secretion of 130 kDa CP was demonstrated. The pulse-labelling experiments with [35S]methionine in rats with catheters inserted into the carotid artery and the common bile duct revealed the polar secretion of two distinct CP species differing in molecular structure and secretion rate. The slowly secreted CP isoform is the authentic serum CP, while the rapidly secreted CP is the specific biliary CP. The physiological function of biliary CP and its role in the pathogenesis of Wilson's disease are discussed.
Puchkova
L V
LV
Aleĭnikova
T D
TD
Verbina
I A
IA
Zakharova
E T
ET
Pliss
M G
MG
Gaĭtskhoki
V S
VS
D000818:Animals; D001345:Autoradiography; D001646:Bile; D001692:Biological Transport; D001769:Blood; D002570:Ceruloplasmin / Q000096:biosynthesis* / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D066298:In Vitro Techniques; D007700:Kinetics; D008099:Liver / Q000378:metabolism*; D008297:Male; D008970:Molecular Weight; D051381:Rats
D002570:Ceruloplasmin
Biosintez dvukh molekuliarnykh form tseruloplazmina v pecheni krysy i ikh poliarnaia sekretsiia v krovotok i v zhelch'.