The Effects of Chronic Infusion of Norepinephrine on Cardiac Structure, Function and Biochemistry — Physiological vs. Pathological Hypertrophy

Abstract

An observation published by our group in 1969 has lead to a continuing series of studies into the mechanisms of norepinephrine (NE) induced hypertrophy (1). We observed that after banding the canine pulmonary artery for three months, or more, myocardial cell lengths increased not only in the right ventricle, as expected, but in the left ventricle as well (1). Because there was no hemodynamic reason for the left ventricle to enlarge its cell size, we hypothesized that a hormone or a substance may be elaborated from the right ventricle and act on the left ventricle to cause its hypertrophy. NE, a major biologically active substance in the ventricle, was proposed as a likely inducer of left ventricular hypertrophy. After a review of studies on myocardial structural, functional and biochemical alterations produced by the infusions of NE, we will attempt to formulate a unifying hypothesis for the fundamental mechanisms involved in myocardial hypertrophy utilizing both our data and the contributions of several other groups.