Thyroid in Pulmonary Injury Induced by 02 in High Concentration at Atmospheric Pressure.

Abstract

Summary 1. In a study of the influence of O₂ in high concentrations (94% at atmospheric pressure) it was found that the administration of desiccated thyroid augments the adverse effects of O₂ on normal and on hypophysectomized rats as shown 1) by a shortening of both the onset of the symptoms—hyperpnea, lethargy, dyspnea, coma—and the survival times, and 2) by increasing the severity of macroscopic pathological changes, including massive pleural effusion and hydrothorax, congestion, oedema and hepatization of the lungs and enlargement and congestion of the liver. 2. The pronounced protection which hypophy-sectomy provides against the adverse pulmonary effects of increased O₂ is in large degree counteracted by the administration of thyroid to the hypophysectomized animal. This protection is, therefore, attributable not only to the loss of adrenocortical principles but also to the loss of thyrotropin. The possible involvement of an increased CO₂ in the thyroid effects is discussed.