Thyroid and adrenal relationships.

A brief review of the actions of adrenal medullary and thyroid hormones is presented and the ways in which they interact are examined. It is concluded that thyroid hormone produces the necessary intracellular environment without which the steady state and emergency actions of cathecholamines would be vitiated. In hyperthyroidism the increased concentration of thyroid hormones results in a lowering of the threshold for catecholamine action. For this reason it is possible to alleviate many of the symptoms of thyrotoxicosis by means of drugs which block β-adrenergic receptors. Attention is also drawn to the simultaneous occurrence of thyroid and adrenal disease, in the hope that this will encourage the search for further links in this field of endocrinology.