筋肉タンパク質の分解機構に関する栄養生化学的研究  [in Japanese] Nutritional and Biochemical Studies on Muscle Protein Degradation  [in Japanese]

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Author(s)

Abstract

Skeletal muscle protein is very important for protein and amino acid metabolism in the homeostasis of the whole body, because skeletal muscle accounts for the largest amount of tissue. Therefore, it is necessary to measure the rate of muscle protein synthesis and degradation. Urinary Nτ-methylhistidine (MeHis) is used as an index of myofibrillar protein degradation. It was demonstrated in this study using rats that 75% of MeHis in urine originated from skeletal muscle and that 25% originated from skin and intestine. Furthermore, it was suggested that there was a rapid turnover of myofibrils, because the specific radioactivity of MeHis in urine and muscle protein differed after administration of radioactive methionine. Several factors influencing muscle protein degradation were studied using MeHis release from perfused hindquarter muscles and isolated muscles. Insulin, known to be an anabolic hormone, it inhibited the degradation of muscle protein, particularly myofibrillar protein, in diabetic rats. Cysteine proteinases might be involved in muscle protein degradation, because leupeptin inhibited the release of MeHis and tyrosine from isolated muscle. Muscle protein degradation was also affected by the modification of muscle protein by active oxygen species or free radicals by feeding rats a vitamin E-deficient diet or iron overload. In these studies, a new method for determination of MeHis was developed, capable of measuring low concentrations of MeHis in plasma and medium. This method would allow acute changes in muscle protein degradation to be evaluated.

Journal

  • Nippon Eiyo Shokuryo Gakkaishi

    Nippon Eiyo Shokuryo Gakkaishi 48(5), 347-355, 1995-10-10

    Japan Society of Nutrition and Food Science

References:  87

Codes

  • NII Article ID (NAID)
    10008562882
  • NII NACSIS-CAT ID (NCID)
    AN00311992
  • Text Lang
    JPN
  • Article Type
    REV
  • ISSN
    02873516
  • NDL Article ID
    3645045
  • NDL Source Classification
    SC226(衛生学・公衆衛生--食品衛生・栄養学)
  • NDL Source Classification
    ZS8(科学技術--医学--解剖学・生理学・生化学)
  • NDL Call No.
    Z19-53
  • Data Source
    CJP  NDL  J-STAGE 
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