[Clinical course and pathophysiology of hyperthermia]

In 221 hyperthermic baths with 138 healthy volunteers thermoregulatory, circulatory, respiratory, renal, hematological, immunological, and endocrinological function values and sudomotoric activity have been determined. The endocrinological investigations demonstrate an increased glucocorticoidal activity (eosinopenia, T-lymphocytopenia) while plasmatic cortisole concentrations are slightly decreased. This discrepancy may be explained by an increased dissociation of biologically active cortisole and transcortin and by a more rapid activation of the steroid-receptor complex within the endocrine target cell. During a series of ten hyperthermic baths on ten consecutive days mineralocorticoidal activity during hyperthermia is increased (sudomotor activity, excretion of urine and sodium); urinary excretion of aldosterone does not change. These results indicate an increased sensitivity of the mineralocorticoidal target cell after adaptation to heat. The hypothesis can be confirmed by experiments with aldosterone i.v.