title: Systemic alterations in ornithine decarboxylase activity caused by colon cancer in mice.
abstract: Tumors are known to cause profound changes in host biology, but the mechanisms responsible for these changes remain unclear. Ornithine decarboxylase (ODC) is a rate-limiting enzyme that catalyzes the biosynthesis of polyamines. The purpose of this study was to examine the effects of MC-26 tumor burden on ODC activity in the gastrointestinal tract, kidney and liver of mice. Forty-four Balb/c mice were randomly divided into 2 groups and the test group was pair-fed (to control). Group 1 was the tumor-free control. Group 2 was inoculated subcutaneously with 5 x 10(5) MC-26 cells. The ODC activity in the kidney and liver of tumor-bearing mice was significantly lower compared to tumor-free controls at sacrifice. ODC activity in the colon increased almost 4-fold. These results suggest that the presence of MC-26 tumor causes systemic effects that alter ODC activity. The tumor may elaborate a substance that suppresses ODC activity in some normal tissues while stimulating ODC activity in the tissue from which the tumor was derived.
authors.affiliation: Department of Surgery, University of Texas Medical Branch, Galveston 77550.
authors.forename: R
authors.initials: R
authors.lastname: Saydjari
authors.forename: R D
authors.initials: RD
authors.lastname: Beauchamp
authors.forename: C M
authors.initials: CM
authors.lastname: Townsend
authors.forename: J C
authors.initials: JC
authors.lastname: Thompson
mesh_terms: D000818:Animals; D003106:Colon / Q000201:enzymology; D003110:Colonic Neoplasms / Q000201:enzymology*; D004064:Digestive System / Q000201:enzymology; D007668:Kidney / Q000201:enzymology; D008099:Liver / Q000201:enzymology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D009368:Neoplasm Transplantation; D009955:Ornithine Decarboxylase / Q000378:metabolism*
chemical_list: D009955:Ornithine Decarboxylase