Selenium Deficiency in Fisher-344 Rats Decreases Plasma and Tissue Homocysteine Concentrations and Alters Plasma Homocysteine and Cysteine Redox Status

• Published in: The Journal of nutrition Vol. 132; no. 6; pp. 1122 - 1128
• Main Authors: Uthus, E.O., Davis, C.D., Yokoi, K.
• Format: Journal Article
• Language: English
• Published: Bethesda, MD Elsevier Inc 01.06.2002; American Society for Nutritional Sciences; American Institute of Nutrition
• Subjects: adverse effects; Amino acids; animal models; Animals; antioxidant activity; antioxidants; Betaine-Homocysteine S-Methyltransferase; Biochemistry; Biological and medical sciences; blood serum; Chemical elements; cysteine; Cysteine - blood; Cysteine - metabolism; Dose-Response Relationship, Drug; Feeding. Feeding behavior; free radical scavengers; Fundamental and applied biological sciences. Psychology; glutathione; Glutathione - metabolism; Glutathione Peroxidase - metabolism; homocysteine; Homocysteine - blood; Homocysteine - metabolism; Kidney - metabolism; Liver - drug effects; Liver - enzymology; Male; Metabolism; Methionine - blood; Methionine - metabolism; methyltransferases; Methyltransferases - metabolism; Myocardium - metabolism; nutrient deficiencies; nutritional adequacy; nutritional status; Oxidation-Reduction; oxidative stress; Rats; Rats, Inbred F344; redox reactions; Rodents; selenium; Selenium - administration & dosage; Selenium - deficiency; Selenium - metabolism; transsulfuration; Vertebrates: anatomy and physiology, studies on body, several organs or systems; homocysteine; GSSG; glutathione; MS; cysteine; GPT; GOT; CS; BHMT; TCA; selenium; SAM-S; CTH; transsulfuration; SAH; GSH; SAM; CPK; Micronutrient; Vertebrata; Cysteine; Mammalia; Homocystein; Rat; Deficiency; Rodentia; Trace element (nutrient); Selenium; Inorganic element
• ISSN: 0022-3166; 1541-6100; 1541-6100
• DOI: 10.1093/jn/132.6.1122

The purpose of the present study was to determine the effect of graded amounts of dietary selenium on plasma and tissue parameters of methionine metabolism including homocysteine. Male weanling Fisher-344 rats (n = 7–8/group) were fed a selenium-deficient, torula yeast-based diet, supplemented with 0 (selenium deficient), 0.02, 0.05 or 0.1 μg (adequate) selenium (as selenite)/g diet. After 61 d, plasma total homocysteine and cysteine were decreased (P < 0.0001) and glutathione increased (P < 0.0001) by selenium deficiency. The concentrations of homocysteine in kidney and heart were decreased (P = 0.02) by selenium deficiency. The activities of liver betaine homocysteine methyltransferase, methionine synthase, S-adenosylmethionine synthase, cystathionine synthase and cystathionase were determined; selenium deficiency affected only betaine homocysteine methyltransferase, which was decreased (P < 0.0001). The ratios of plasma free reduced homocysteine (or cysteine) to free oxidized homocysteine (or cysteine) or to total homocysteine (or cysteine) were increased by selenium deficiency, suggesting that selenium status affects the normally tightly controlled redox status of these thiols. Most differences due to dietary selenium were between rats fed 0 or 0.02 μg selenium/g diet and those fed 0.05 or 0.1 μg selenium/g diet. The metabolic consequences of a marked decrease in plasma homocysteine and smaller but significant decreases in tissue homocysteine are not known.