The Effect Of Adh On Eccrine Sweating In The Rat**From The Gillette Company Research Institute, 1413 Research Boulevard, Rockville, Maryland 20850.

The effect of antidiuretic hormone on human eccrine sweating has been studied by numerous investigators, but the results are inconclusive. To test the hypothesis that this hormone can influence secretory rate by the sweat gland, the eccrine glands in the foot-pads of the normally hydrated rat were used as a model system. It was found that a local subcutaneous injection of 20 mUnits of ADH per foot reduced the initial sweat rate by about 50%. Further, the duration of the secretory response was shortened substantially in the hormone's presence. Sodium concentrations in sweat of ADH-treated rats were significantly higher than those in control animals, but the total amounts excreted were much less than control values. The hormone also affected sweat potassium concentrations, but much less dramatically. Experiments with an analog of ADH, Octapressin (PLV-2), indicated that ADH reduced sweat rate primarily because of its antidiuretic rather than its vasoconstrictive properties. The injection of PLV-2 in concentrations similar to ADH's vasoconstrictive activity but less than its antidiuretic activity failed to reduce the secretory rate as much as did the parent compound. Sodium levels, too, were intermediate between those for controls and those under the influence of ADH. It is concluded that ADH is capable of reducing sweat rate and increasing sweat sodium concentration. Total sweat sodium excretion, however, is less in the hormone's presence. The action of APR appears to be a function of its water conserving characteristic rather than its vasoconstrictive property