Experiments were conducted to examine the role of dietary selenium (Se) and changes in antioxidant capacity during DMBA-induced mammary carcinogenesis. Weanling rats were fed graded amounts of Se in an AIN-76 diet, modified to approximate the amount and type of dietary fat consumed in Canada. Animals fed 3-4 ppm Se had a reduced tumor incidence but there was evidence of chronic Se toxicity. Low Se did not elevate tumor incidence. Thus, supplemental dietary Se did not offer any protection in reducing the incidence of cancer when rats were fed a diet representative of North American intakes of fat. Blood GSHPx activity was elevated in rats that remained free of tumors (NT group) compared to animals that would eventually develop tumors (WT group). SOD activity was reduced in WT and NT rats, but appeared to be related to carcinogen administration. These differences were observed before tumor development and over a wide range of Se intakes. WT rats excreted more $ sp{75}$Se compared to both control and NT rats. These changes, however, were not reflected in elevated lipid peroxidation. Thus, one of the protective mechanisms during carcinogenesis may be the capacity of the animal to elevate GSHPx activity.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.75681 |
| Date | January 1988 |
| Creators | L'Abbé, Mary R. |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Department of Animal Science.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 000573252, proquestno: AAINL45969, Theses scanned by UMI/ProQuest. |
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