[Water and potassium metabolism in functional disturbances of the thyroid gland (author's transl)]

Total body water, extracellular water (bromide space), plasma volume and total body potassium were evaluated in hypothyroid (n = 24) and hyperthyroid (n = 18) patients and in controls (n = 10). Whereas the relative extracellular water was the same in all groups investigated, the relative intracellular water was found to be reduced in hyperthyroidism and increased in hypothyroidism (p less than 0.05). As to plasma volume there were no significant differences. A negative correlation between total body potassium and functional disturbance of the thyroid (T4) is thought to be attributable to an alteration of the lean body mass.