Immersion Hypothermia: Effect of Glycine.

Abstract

With the marked increase in accidental human hypothermia due to the greater number of individuals presently exposed to arctic conditions, agents are needed which will increase body heat production and hence bolster body defenses against cold. Glycine, an amino acid with a high specific dynamic action, increased finger temperatures when fed to enthermic human subjects. In 20 experiments, apparently normal dogs were cooled from normal temperature to a rectal temperature of 26[degree] C by immersion in 8[degree] C ice water and rewarmed to a rectal temperature of 37[degree] C by immersion in 43[degree] C water; this procedure was performed twice on each animal. During 1 procedure an infusion of 5% glycine (25 g, 100 cal) was given, and during the 2d procedure an infusion of glycose (25 g, 100 cal) was given. O2 consumptions were measured and heat productions were calculated. Glycine prolonged the average cooling time by 34 minutes and decreased rewarming time by 35 minutes, and significantly increased heat production. Its ability to elevate the metabolic rate was greatly diminished below 28[degree] rectal. The calculated increase in heat production by glycine was of a magnitude that can be explained on the basis of its specific dynamic action.