Comparison of human myofibrillar protein catabolic rate derived from 3-methylhistidine excretion with synthetic rate from muscle biopsies during L-[alpha-15N]lysine infusion.

Abstract

1. Urine was collected in five healthy men over 10--14 days, with fasting blood samples on days 1, 5 and 10, whilst they consumed a standard creatine-free diet, which was quantitatively related to their body surface area. 2. The urinary excretion of 3-methylhistidine fell to a plateau by day 5 in all subjects. Myofibrillar protein catabolic rate calculated from the mean value of 3-methylhistidine excretion from day 5 to day 10 averaged 1.21 g day-1 kg-1 body weight. The average turnover of muscle myofibrillar protein was calculated to be 2.16%/day. 3. From a previous study using continuous intravenous infusion of L-[alpha-15N]lysine with serial muscle biopsies on the same subjects, the mean myofibrillar protein synthetic rate was calculated to be 0.82 g day-1 kg-1 body weight, and the mean turnover rate was 1.47%/day of total muscle myofibrillar protein. 4. The estimations of myofibrillar protein turnover rate derived from the two methods are compared and the differences discussed.

• Authors: R O McKeran, D Halliday, P Purkiss
• Journal: Clinical science and molecular medicine (Clin Sci Mol Med) Vol. 54 Issue 5 Pg. 471-5 (May 1978) ISSN: 0301-0538 [Print] England
• PMID: 750147 (Publication Type: Comparative Study, Journal Article)

Chemical References

• Methylhistidines
• Muscle Proteins
• Histidine
• Creatinine
• Lysine

Topics

• Adult
• Creatinine (urine)
• Histidine (analogs & derivatives)
• Humans
• Lysine (metabolism)
• Male
• Methylhistidines (urine)
• Middle Aged
• Muscle Proteins (biosynthesis, metabolism)
• Myofibrils (metabolism)
• Time Factors