Accidental Hypothermia: Endocrine Function During Recovery1

Plasma thyrotropin (TSH), thyroxine (T4), free T4, triiodothyronine (T3), growth hormone (GH), insulin (IRI), cortisol, glucose and osmolality were serially determined in a group of twelve patients admitted to a city hospital for accidental cold exposure with rectal temperature below 90 F. Plasma TSH and free T4 were constant. There was a significant decrease in plasma T4 and T3 which paralleled but was greater than the decrease in osmolality. Plasma cortisol increased over the first 7 hr of rewarming and then showed individual variation. Plasma GH and IRI concentrations were erratic and were independent of glucose concentration. Two of the three patients given 100 μg of synthetic thyrotropin releasing hormone (TRH) demonstrated a prompt rise in plasma TSH and T3. It is concluded that during hypothermia: 1) the hypothalamic-pituitary-thyroid axis is intact, 2) hypothermia is not a stimulus for TSH release in man, 3) neither GH or IRI nor their response to plasma glucose show a consistent change, 4) plasma...