Possible function of carbohydrate on glycoproteins secreted by the pig uterus during pregnancy |
| |
| Authors: | R Michael Roberts Dr George A Baumbach Philippa T K Saunders Thomas J Raub Randall H Renegar Fuller W Bazer |
| |
| Institution: | (1) 158 Animal Sciences Research Center, University of Missouri, 65211 Columbia, MO, USA;(2) Departments of Animal Science and Biochemistry, University of Missouri, 65211 Columbia, MO, USA;(3) Department of Biochemistry and Molecular Biology, University of Florida, USA;(4) Department of Animal Science, University of Florida, 32611 Gainesville, FL, USA;(5) Present address: Department of Animal Science, University of Tennessee, 37737 Knoxville, TN, USA;(6) Present address: Zoological Society of London, Regents Park, NWl 4RY London, UK;(7) Present address: Drug Delivery Systems, Upjohn Co., 49001 Kalamazoo, MI, USA;(8) Present address: Department of Anatomy, East Carolina State University, 27834 Greenville, NC, USA |
| |
| Abstract: | Uteroferrin is a purple iron-containing acid phosphatase secreted by the porcine uterus under the influence of the hormone, progesterone. It is synthesized by the glandular epithelial cells of the uterine endometrium and during pregnancy is taken up by specialized structures (areolae) opposite each uterine gland. Uteroferrin is then released into the fetal circulation and cleared by the liver or fetal kidney. A major role in iron transport to the fetus has been proposed. Uteroferrin, as purified from uterine secretions of pigs, possesses mainly high mannose (predominately Man5 and Man6 chains. These oligosaccharide chains of uteroferrin appear to be responsible for its binding and uptake by reticuloendothelial cells of the fetal liver which is the major site of erythropoiesis of the fetus. Uteroferrin, although implicated in transplantal iron transport, also possesses many of the properties of a lysosomal enzyme and, when newly synthesized, carries the so-called lysosomal recognition marker, mannose 6-phosphate. The phosphate group is masked by a covering N-acetylglucosamine residue, a feature which may account for its secretion rather than retention within lysosomes. Evidence is also presented that the oligosaccharide chains of newly synthesized uteroferrin are larger than those of the mature form and are trimmed after secretion. The phosphate group is also removed. It is not clear whether uteroferrin carbohydrate is implicated in the movement of the glycoprotein across the placenta as well as its uptake by the fetal liver. |
| |
| Keywords: | glycoprotein oligosaccharide uteroferrin placenta pregnancy |
| 本文献已被 SpringerLink 等数据库收录！ |
|
