title: Cobalamin-mediated regulation of transcobalamin receptor levels in rat organs.
abstract: Total gastrectomy (TG) causes cobalamin (Cbl) deficiency followed by increases in tumor necrosis factor (TNF)-alpha levels in the spinal cord (SC) of the rat. In order to understand how Cbl deficiency may influence cell Cbl transport, we have measured by immunoblotting protein levels of the receptor for the Cbl-transcobalamin (TC) complex (TC-R) in both animal and cell models. TC-R protein levels were elevated in the total membranes of duodenal mucosa, kidneys, liver, and SC of rats made Cbl-deficient (Cbl-D) by means of TG or feeding with a Cbl-D diet. Postoperative Cbl-replacement treatment normalized the TC-R protein levels in each of the tested organs, regardless of whether this treatment was given during the first two post-TG or during the third and fourth post-TG mo. In Caco-2 cells, progressively increasing TNF-alpha concentrations supplemented to culture medium induced an up-regulation of TC-R protein levels. We provide the first evidence of the regulation of a Cbl-specific receptor by the vitamin itself in some rat organs.
authors: Department of Medicine, Medical College of Wisconsin, 5000 West National Avenue, Milwaukee, 53295 WI, USA.
authors: Seema
authors: S
authors: Kalra
authors: Rajiv
authors: R
authors: Ahuja
authors: Elena
authors: E
authors: Mutti
authors: Daniela
authors: D
authors: Veber
authors: Shakuntla
authors: S
authors: Seetharam
authors: Giuseppe
authors: G
authors: Scalabrino
authors: Bellur
authors: B
authors: Seetharam
mesh_terms: D000818:Animals; D018938:Caco-2 Cells; D004386:Duodenum / Q000502:physiology; D005743:Gastrectomy; D006801:Humans; D007413:Intestinal Mucosa / Q000502:physiology; D008099:Liver / Q000502:physiology; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D011956:Receptors, Cell Surface / Q000502:physiology*; D013116:Spinal Cord / Q000502:physiology; D014805:Vitamin B 12 / Q000502:physiology*; D014806:Vitamin B 12 Deficiency / Q000503:physiopathology
chemical_list: D011956:Receptors, Cell Surface; C028176:transcobalamin receptor; D014805:Vitamin B 12