Plasma clearance kinetics of the amyloid-related high density lipoprotein apoprotein, serum amyloid protein (apoSAA), in the mouse. Evidence for rapid apoSAA clearance.
The plasma clearance kinetics of the amyloid-related high density lipoprotein (HDL) apoprotein serum amyloid protein (apoSAA) was examined in BALB/c mice by two different methods, using labeled 125I-apoSAA-rich HDL and unlabeled plasma apoSAA (clearance monitored by radioimmunoassay). The plasma half-life of apoSAA, estimated by both methods, was on the order of 75-80 min, as compared with a value of approximately 11 h for mouse apoA-I. In trace-labeling studies, the rapid plasma clearance of both major 125I-labeled apoSAA isotypes was observed; this metabolic behavior was unique to these polypeptides among HDL apoproteins. The property of rapid plasma clearance was lost upon purification and reconstitution of 125I-apoSAA with HDL, indicating that this property is labile to denaturing conditions. Studies aimed at determining the metabolic fate of 125I-apoSAA gave no evidence for either the selective excretion of 125I-apoSAA or clearance to unique tissue sites as compared with other 125I-HDL apoproteins.
D000818:Animals; D001053:Apolipoproteins / Q000097:blood* / Q000652:urine; D004591:Electrophoresis, Polyacrylamide Gel; D006207:Half-Life; D007700:Kinetics; D008075:Lipoproteins, HDL / Q000097:blood*; D008099:Liver / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D009928:Organ Specificity
D001053:Apolipoproteins; D008075:Lipoproteins, HDL; C035165:apolipoprotein SAA