The free amino acids in eccrine sweat collected from the forearms of 20 healthy trained and 20 healthy untrained men during controlled exercise were determined quantitatively using ion exchange column chromatography. Sweat was deproteinized by adding an equal volume of 5% sulphosalicylic acid. The amino acid concentrations showed a constant qualitative pattern in sweat and large individual differences. Essential amino acids, such as isoleucine, leucine, lysine, methionine, phenylalanine, and valine were excreted in relatively small amounts. As compared to the trained men, untrained men showed statistically significantly higher concentrations in sweat for the following amino acids: Alanine, arginine, glycine, histidine, isoleucine, leucine, lysine, ornithine, phenylalanine, serine, taurine, threonine, tyrosine, and valine. No significant differences were found for citrulline, cystine, ethanolamine, and methionine. The comparison of the amino acid excretions in sweat obtained under controlled exercise and in urine showed that the amounts of amino acids excreted in sweat under controlled exercise were comparable to the losses of amino acids in urine.
Using ion-exchange column chromatography we measured the free amino acids in eccrine sweat collected from the forearms of 20 healthy young men at intervals of 15, 30, and 45 min during sauna bathing. In comparison with the amino acid concentrations determined after 15 min of sweating (100%) a significant and uniform decrease occurred in the concentrations of all amino acids examined after a further 15 min (65%), with a further decrease after another 15 min (45%). These results indicate that either the mechanism of excretion of amino acids in the secretory cells of the eccrine sweat glands, or the reabsorption of amino acids by the ductular cells, or the combination of both mechanisms are similar for all the amino acids examined here.
1. The comparison of the women taking oral contraceptives with the women not taking oral contraceptives showed no qualitative or significant quantitative differences in the excretion of amino acids in thermal sweat collected from the total body surface. 2. The comparison of the trained women with the untrained women neither revealed qualitative or significant quantitative differences in the excretion of amino acids in thermal sweat collected from the total body surface. 3. As compared to the trained men, untrained men excreted in thermal sweat collected from the total body surface significantly more alanine, arginine, citrulline, cystine, glycine, histidine, isoleucine, leucine, lysine, phenylalanine, serine, threonine, tyrosine, and valine. 4. The sex-specific comparison of the amino acid excretion in sweat showed that men had a significantly increased excretion of cystine, histidine, leucine, and taurine. Proline was detected only in the sweat of women. 5. The quantitative results obtained for the amino acid excretions during 12 min of sauna bathing suggest that persons exposed to hard, physical activity and/or high environmental temperatures have quite equal amino acid losses in sweat and in 24 h urine.
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