Antioxidant associated chemoprevention by selenomethionine in murine tumormodel

Effectiveness of selenium in different forms like sodium selenite, selenocy steine and selenomethionine has been compared in four different doses, name ly 4, 6, 8 and 10 ppm of each, in terms of their bioavailability and prolon gation of survival of Dalton's lymphoma (DL) bearing mice. Selenomethionine , at a dose of 8 ppm, was found to be the most bioavailable and least cytot oxic form that was capable of increasing the life span of the tumour bearin g hosts maximally (almost two-fold). Beneficiality of selenomethionine has also been studied by observing continuous changes brought about by this com pound on the glutathione (GSH) level, glutathione peroxidase (GPx) activity and extent of lipid peroxidation in the hepatic tissue of the tumour beari ng hosts, which are indispensable for a cell to function normally and are f ound to exhibit significantly altered behaviour in neoplastic cells. Seleno methionine caused the maintenance of high steady state GSH level and a norm al GPx activity during the fist phase of tumour growth. It also controlled lipid peroxidation during the first 15-20 days following tumour transplanta tion. These conditions helped in the maintenance of intracellular redox bal ance, cellular integrity and metabolic rhythms of cells in DL bearing mice receiving selenomethionine.