Free Amino-acids in Human Sweat from Different Parts of the Body

Abstract

THE presence of free amino-acids in human sweat has been known since 1910 when Embden and Tachau¹ isolated serine from this secretion. In 1946, Hier, Cornbleet and Bergeim² identified arginine, histidine, isoleucine, leucine, lysine, phenylalanine, threonine, tryptophane, tyrosine and valine in human sweat; they were also able to demonstrate that the amount of amino-acids secreted in sweat is independent of the diet and of variations in amino-acid levels in the blood; Rothman and Sullivan³ found two additional amino-acids to be present in sweat, ornithine and citrulline. This observation, together with the high urea level of sweat⁴, led to the hypothesis that urea is formed in the sweat glands^2,3. Hamilton⁵, and Oró and Skewes⁶, using ultra-micro methods, found the relative concentrations of amino-acids on the surface of the fingers of ten subjects to be essentially constant. Other authors⁷ who sampled sweat from the whole body surface, rather than from a single area, reported greater individual differences.