RELATIONSHIP BETWEEN BLOOD CHOLESTEROL AND INCREASED METABOLISM FROM DINITROPHENOL AND THYROID 1

Abstract

It has long been known that certain manifestations of hyperthyroidism follow directly upon the increased metabolic rate, but the causes of other changes in the disease are not so obvious. Dinitrophenol increases metabo-lism by a peripheral action in the tissues, and apparently has no other con-comitant actions in therapeutic doses (1 to 10); thus it is available for studying isolated effects of increased metabolism and determining the im-portance of the latter in thyrotoxicosis. Anxiety, palpitation, and tremor, which are commonly found in hyper-thyroidism, are absent when the metabolism is correspondingly increased by dinitrophenol, but increased perspiration and sensations of warmth are present in both (7). The latter symptoms, therefore, are apparently due directly to the heightened metabolism. Another difference from thyroid or thyroxine (6) is absence of accelerated metamorphosis of tadpoles. The heightened metabolism caused by excess thyroid is associated with an in-creased pulse pressure, while that of dinitrophenol is not accompanied by an increased output, as judged from pulse pressure-pulse rate formulae. However, some change in output can be demonstrated in experimental ani-mals with metabolic rates beyond those seen clinically (8). Apparently, with dinitrophenol the tissues get their greater oxygen supply, at least partly, by increased deoxygenation of the blood. In our experience after dinitrophenol, and after dinitro-o-cresol (19), patients with severe degrees of hypothyroidism fail to get symptomatic relief even though the metabolic rate is restored to normal by these drugs. Thus, the ability to increase me-tabolism appears to be the only common action of dinitrophenol and thyroid so far studied. This paper deals with a blood-constituent which is quantitatively modi-fied in thyroid disease, namely, cholesterol. The concentration df blood cholesterol is usually raised in hypothyroidism, and lowered slightly in hyperthyroidism. Therefore, we have studied the changes in cholesterol after dinitrophenol medication to determine whether it varies with the