Neuroendocrine responses to cold stress in normal subjects and depressives

In order to assess the effects of cold stress on neuroendocrine function in persons with affective disorders, 11 normal subjects and eight depressed patients were subjected to a well-defined thermal stress in a cold chamber at 10 degrees C. Metabolic rate, skin and rectal temperature, and TSH, T4, T3, growth hormone, prolactin, and cortisol were measured simultaneously for 45 minutes prior to cold exposure and for 60 minutes in the cold. All subjects experienced robust changes in skin temperature and metabolic rate during cold exposure, while maintaining core temperature throughout. There were no changes in any of the neuroendocrine parameters during exposure to cold stress in either the controls or the depressives, although depressives had somewhat higher T4 and lower T3, TSH, and GH throughout the study. These findings indicate that hormones of these neuroendocrine axes are unresponsive to acute, moderate cold stress in normal man and that depressives show no greater reactivity than normals.