Effects of Methionine Supplementation on the Metabolism of S-adenosylmethionine during Long-term High Selenium Consumption in Rats

• Main Authors: Chen, Chih-Shyang, 陳智祥
• Other Authors: 駱菲莉
• Format: Others
• Language: zh-TW
• Published: 1997
• Online Access: http://ndltd.ncl.edu.tw/handle/17782495842454231452

碩士 === 輔仁大學 === 食品營養學系 === 85 === The purpose of this study was to investigate the effect of methionine supplementation on metabolism of SAM, Se status and growth of rats during long term high Se consumption. After 1 week of adaptation on normal diet (O.1 mg Se/kg diet, 0.3% methionine, wt/wt), 86 weanling male SD rats were randomly assigned to receive a Torula yeast-based diet with various levels of Se and different levels of methionine supplement (0, 0.3, 0.6%, wt/wt) for 12 weeks. Results indicated that hepatic SAM concentration and SAM:SAH ratio decreased significantly as dietary Se level increased (P<0.005), probably due to the increased needs of SAM to excrete excessive Se by methylation. Methionine supplementation tended to raise hepatic SAH concentration (P=0.0848). Long-term high Se consumption raised hepatic Se concentration, retarded growth of rats and caused elevation in relative organ weight and pathological damage in rat liver. However, 0. 6% of dietary methionine supplementation reduced liver Se accumulation and maintained optimal growth and liver morphology of rats in 5mg Se/kg diet group. Long term high Se consumption did not further increased SeGPX activities of liver and erythrocytes, and methionine supplementation did not have consistent influence on indices of Se status. In conclusion, long term high Se consumption (5mg Se/kg diet, 12 weeks) resulted in decreased hepatic SAM concentration, SAM:SAH ratio and growth of rats, liver Se accumulation and pathological changes. Methionine supplementation of 0.6% may reduce Se toxicity by lowering liver Se accumulation thus maintaining optimal growth of rats.