Résumé
Free radicals are increasingly formed in diabetes mellitus by the auto oxidation of glucose and glycosylated proteins. Oxidative stress and proteinglycosylation are closely related processes and have been shown to contribute to the development of complications in diabetes mellitus. The extent of protein glycosylation was assessed in alloxan induced diabetic rats after being treated with 50 mg of betacarotene for 40 days. The level of fructosamine and glycosylated haemoglobin was comparison with non treated diabetic rats. The results indicate the beneficial role of betacarotene in reducing diabetic complications like glycosylation in experimental diabetic rats.
Sujets)
Animaux , Antioxydants/pharmacologie , Glycémie/métabolisme , Diabète expérimental/sang , Fructosamine/sang , Glycosylation/effets des médicaments et des substances chimiques , Hémoglobine glyquée/métabolisme , Rats , Rat Wistar , Bêtacarotène/pharmacologieRésumé
An enzyme catalysing the hydrolysis of a-tocopheryl acetate was characterised in chicken liver. The enzyme was localised in the microsomes, had an optimum pH 8·6 and a Km value of 0·5 mM. The enzyme did not hydrolyse retinyl acetate, cholesteryl acetate and ethyl acetate, thus indicating a high degree of specificity. a-Tocopheryl acetate hydrolase required bile salts as a specific cofactor. The results suggested a role for this enzyme in the absorption of vitamin E.
Résumé
Peroxidation of the unsaturated lipid of tissue homogenates is an established method to assess the antioxidant or vitamin E status of animals. In the present study the spontaneous lipid peroxidation in air of rat brain homogenates is reported. The effects of various factors like pH, time, concentration of tissues, temperature, ferrocompounds and catalysis by added tissues like liver are described. Rat brain homogenates appear to be a suitable preparation for in vitro studies of lipid peroxidation.