[Effect of methionine supplementation on the selenium bioavailability in rats fed on grains from Keshan disease endemic area].
In order to study the effect of dietary methionine on tissue selenium and glutathione peroxidase activity(GPX) in rats fed on grains from Keshan Disease endemic area, a nonpurified selenium (Se) deficient diet (containing Se 0.007 mg/kg diet) taken from Keshan Disease endemic area was supplemented with selenomethionine (SeMet) to provide selenium content in diet for 0.007, 0.06 and 0.50 mg/kg and added or not added with DL-methionine (Met) 4 g/kg to make 6 kinds of diet. Fifty four male weanling Wistar rats were randomly divided into 6 groups, consuming each one of the 6 diets for 8 weeks. The Se content and GPX activity in tissues of animals with Met supplementation were compared with those without Met supplementation. The results showed that adding Met did not result in significant changes of tissue Se content and GPX activity in animals having dietary Se of 0.007 mg/kg, except for lower muscle Se content. However, in animals having dietary Se of 0.06 mg/kg and supplementing Met resulted in selenium redistribution in tissues-decrease of Se content in muscle, increase of Se content in liver and blood and significant elevation of GPX activity in all tissues. In animals having methionine-added and dietary Se of 0.50 mg/kg, tissue Se content declined to various extent, while GPX activity remained unchanged. The results suggest that SeMet (main chemical form of Se in cereals) is preferentially incorporated into body protein when dietary methionine is limited. Once Met is supplemented, dietary SeMet would provide more Se for the syntheses of GPX and other selenoproteins. The results further suggest that marginal deficiency in sulfur-containing amino acids in the diet from Keshan Disease endemic area might be an additional factor for the development of Keshan Disease under selenium deficiency.
Institute of Nutrition and Food Hygiene, Chinese Academy of Preventive Medicine, Beijing 100050, China.
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Tian
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Qu
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Zhou
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Xu
D000818:Animals; D001682:Biological Availability; D009202:Cardiomyopathies / Q000378:metabolism*; D002523:Edible Grain; D005979:Glutathione Peroxidase / Q000378:metabolism; D008297:Male; D008715:Methionine / Q000008:administration & dosage / Q000494:pharmacology*; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D012643:Selenium / Q000493:pharmacokinetics*
D008715:Methionine; D005979:Glutathione Peroxidase; D012643:Selenium