Glycoprotein biosynthesis during the acute-phase response to inflammation.
Inflammation results in an increase in the levels of a variety of glycoproteins in serum. The glycoproteins that respond in this way are usually referred to as acute-phase reactants. Studies on the acute-phase response of rat alpha 1-acid glycoprotein showed that there was an increase in the liver levels of this glycoprotein at 12 h after turpentine inflammation. This was followed by increased serum levels at 48-72 h after inflammation, suggesting a precursor-product relationship between liver and serum alpha 1-acid glycoprotein. Incorporation studies coupled with measurements of synthesis rates of alpha 1-acid glycoprotein showed that increased synthesis was responsible for the acute-phase response of this protein to inflammation. These studies also showed that albumin was a negative acute-phase reactant. The acute-phase response of alpha 1-acid glycoprotein was accompanied by increased liver pools of UDP-N-acetylglucosamine (UDP-GlcNAc) and UDP-N-acetylgalactosamine (UDP-GalNAc) and increased liver activities of glucosamine-6-phosphate synthase and UDP-GlcNAc 2-epimerase. Activities of galactosyl and sialyl transferases in liver were also elevated and serum sialyl transferase was increased substantially in inflammation, suggesting that it may also be an acute-phase reactant. Liver activities of beta-N-acetylhexosaminidase and beta-galactosidase declined by about 50% at 24 h after inflammation; there was evidence that serum levels of these enzymes increased at 24-72 h after inflammation, suggesting that the lysosomal glycosidases may be released from liver during inflammation.(ABSTRACT TRUNCATED AT 250 WORDS)
D000818:Animals; D006023:Glycoproteins / Q000096:biosynthesis*; D006056:Golgi Apparatus / Q000201:enzymology; D006728:Hormones / Q000097:blood; D006801:Humans; D007249:Inflammation / Q000378:metabolism*; D007375:Interleukin-1; D007700:Kinetics; D008099:Liver / Q000378:metabolism; D009844:Oligosaccharides / Q000096:biosynthesis; D009961:Orosomucoid / Q000096:biosynthesis; D011506:Proteins / Q000494:pharmacology; D012709:Serum Albumin / Q000096:biosynthesis; D012799:Sialyltransferases / Q000032:analysis
D006023:Glycoproteins; D006728:Hormones; D007375:Interleukin-1; D009844:Oligosaccharides; D009961:Orosomucoid; D011506:Proteins; D012709:Serum Albumin; C008270:leukocyte endogenous mediator; D012799:Sialyltransferases