The plasma clearance of human alpha 2-macroglobulin-trypsin complex in the rat is mainly accounted for by uptake into hepatocytes.
Rats were given intravenous injections of 125I-labelled human alpha 2-macroglobulin X trypsin. The half-time of disappearance of radioactivity from arterial blood was 2 min. External counting showed that radioactivity in the liver was maximal by 10 min and then decreased slowly. 87% of the injected dose was recovered in the liver by 10 min. Light- and electron microscopic autoradiography carried out on samples of liver fixed with glutaraldehyde 3 min or 30 min after the injection showed that 85-90% of the grains were over the hepatocytes and 4-9% were over the Kupffer cells. Thus, uptake into hepatocytes, and not into Kupffer cells as believed previously, appears to account for the major part of the uptake of alpha 2-macroglobulin X trypsin by the liver and thereby for its rapid removal from the blood.
Davidsen
O
O
Christensen
E I
EI
Gliemann
J
J
D000818:Animals; D001345:Autoradiography; D001693:Biological Transport, Active; D006801:Humans; D007275:Injections, Intravenous; D007728:Kupffer Cells / Q000378:metabolism; D008099:Liver / Q000378:metabolism* / Q000648:ultrastructure; D008297:Male; D008657:Metabolic Clearance Rate; D051381:Rats; D011919:Rats, Inbred Strains; D014357:Trypsin / Q000378:metabolism*; D000511:alpha-Macroglobulins / Q000378:metabolism*
C028939:alpha-2-macroglobulin-trypsin complex; D000511:alpha-Macroglobulins; D014357:Trypsin