The Circulation Rate in Relation to Metabolism

The relationship between metabolism and the velocity of blood flow in thyroid disease has been studied by numerous investigators (1, 2, 3, 4, 5, 6, 7), all of whom have demonstrated that the velocity of blood flow is increased in hyperthyroidism and decreased in myxedema. In addition, the circulation time or the velocity of blood flow was found to be increased in anemia and decreased in congestive heart failure, while in hypertension, no variation from the normal circulation rate was found. One purpose of this study was to determine if there existed a change in circulation rate in conditions in which the metabolic rate was abnormal, but in which there appeared no evidence of abnormal thyroid function. It is well known that in acromegaly (hyperpituitarism) associated with chromophile pituitary adenomas and hypopituitarism associated with chromophobe tumors the metabolic rate is definitely influenced; in the former it is increased and in the latter decreased. This is now generally considered to be due to secondary changes in thyroid activity from hyperplasia or hypoplasia as the result of increased or decreased effect of the pituitary thyrotropic hormone. The clinical manifestations of myxedema are usually lacking in hypopituitary cases with low metabolism as well as in many instances of hypometabolism of unknown cause. It was our prediction, therefore, that in these cases normal values for circulation time would be found.