AJP - Endocrinology and Metabolism, Vol 248, Issue 5 588-E592, Copyright © 1985 by American Physiological Society
Biphasic changes in 3-methylhistidine excretion in humans after exercise
G. L. Dohm, R. G. Israel, R. L. Breedlove, R. T. Williams and E. W. Askew
We previously reported that 3-methylhistidine excretion was increased in
human subjects after a strenuous bout of exercise. Because other
investigators have not corroborated this finding, we undertook the present
study to investigate the conditions that result in decreased and increased
3-methylhistidine excretion in human subjects after exercise. Four
experiments were performed: a cross-sectional study comparing
3-methylhistidine excretion in endurance-trained subjects with untrained
controls, a longitudinal study of 3-methylhistidine excretion by female
basketball players before the start of the season and again during the
competitive season, an experiment to determine changes in 3-methylhistidine
excretion as a result of 2 h of exercise each day for 7 consecutive days,
and a study to determine changes in 3-methylhistidine excretion during 4-h
intervals after a strenuous exercise bout. The
3-methylhistidine-to-creatinine ratio was approximately 20% higher for
trained than nontrained subjects. In three separate experiments a biphasic
change of 3-methylhistidine excretion was observed in response to exercise
with an immediate decrease in the 3-methylhistidine-to-creatinine ratio
during exercise followed by a prolonged increase. The magnitudes of the
negative and positive responses determine whether one observes an increase,
no change, or a decrease in the total daily excretion of 3-methylhistidine.
