Ni, Cu, Zn, and Pb were measured by atomic absorption spectrometry in sweat samples obtained by the arm-bag technique from 48 healthy adult subjects (33 ♂, 15 ♀ ) during sauna bathing (15 min at 93 °C, dry heat). The men sweated more profusely than the women (volume, in milliliters, of sweat collected: mean, SD, and range: 23 ± 12 (3-55) and 7 ± 3 (2-13), respectively. The concentrations, in µg/liter, (mean, SD, and range) of trace metals in sweat of men and women, respectively, were: nickel, 52 ± 36 (7-180) and 131 ± 65 (39-270); copper, 550 ± 350 (30-1440) and 1480 ± 610 (590-2280); zinc, 500 ± 480 (130-1460) and 1250 ± 770 (530-2620); and lead, 51 ± 42 (8-184) and 118 ± 72 (49-283). In sweat samples from 11 women on oral contraceptives, concentrations of Ni, Cu, Zn, and Pb did not differ significantly from the values in the 15 control women. Sweating is a demonstrably significant route for excretion of trace metals, and sweating may play a role in trace-metal homeostasis. Essential trace metals could conceivably be depleted during prolonged exposure to heat; conversely, sauna bathing might provide a therapeutic method to increase elimination of toxic trace metals.

Amino acids were measured by ion-exchange liquid chromatography in sweat samples obtained from 22 healthy men during sauna bathing. Amino acids were also measured in plasma (collected before breakfast) and urine (24-h collections) from the same subjects. Serine, ornithine, citrulline, and aspartic acid were present in sweat in mean concentrations >10-fold their mean concentrations in plasma. In contrast, glutamine, cystine, α-aminobutyric acid, and α-aminoadipic acid were present in sweat in mean concentrations that were <0.2 times their mean concentrations in plasma. Concentrations of specific amino acids in sweat bore no apparent relationship to their concentrations in urine. Thus, citrulline was abundant in sweat, whereas only traces of citrulline were found in urine. Conversely, glutamine, taurine, cystine, and several other amino acids were abundant in urine but were present in very low or undetectable concentrations in sweat samples. This study indicates that the physiological mechanisms controlling excretion of amino acids in sweat differ fundamentally from those regulating renal excretion of amino acids.

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The specificity of yeast hexokinase for ATP was examined with the aid of a number of synthetic and natural analogs. The main features observed are: The presence of a 2‐amino group either alone or in combination with a 6‐amino or 6‐hydroxyl group inhibits catalysis. The replacement of one or both hydrogen atoms of the 6‐amino group with methyl groups does not have a large effect on either binding or catalysis. The replacement of the nitrogen at position 7 with a carbon atom has virtually no effect. The movement of the glycosidic bond from the N9 to the N3 position has only a moderate effect on both Km and V. The presence of both of the 2′‐ and 3′‐cis hydroxyls in the ribose is important for catalysis. The replacement of ribose with arabinose or glucose produces a large decrease in catalysis. Inhibitor experiments were carried out with the ATP analog containing glucose instead of ribose. It was found to be competitive for ATP and uncompetitive for glucose under the conditions used. These results are consistent with an ordered reaction mechanism.