Relationship between blood pressure and organ weight in the rat

¹ Department of Physiology, University of Florida, College of Medicine, Gainesville, Florida

A relationship exists between systolic blood pressure and the organ to body weight ratios of heart, thyroid, adrenals, and kidneys. In the cases of heart, thyroid, and adrenals, the relationship is sigmoid in character, with the fast-rising portion of the curve beginning at a systolic blood pressure range of 150–159 mm Hg. Beginning at this same blood pressure range, kidney weight ratio increases linearly with increases in blood pressure. It is of interest that these changes occur at a blood pressure range which is generally considered to lie either at the high range of normotension or the low range of hypertension. The only organ weight ratio apparently unrelated to systolic blood pressure level is that of the testis. Some interrelationships among weight ratios of these organs were observed and are discussed.