A new hormone, angiotensin

The renin‐angiotensin system has recently received great emphasis, emerging from a position where even its existence was doubted to one where there is little question that it has powerful effects on several biologic systems. Most important in this changed status have been the determination of chemical structure and synthesis of angiotensin and improved methods of bioassay. Current work concerning the spatial orientation of the angiotensin molecule suggests that a conformation is essential for its action at the receptor site; this work should facilitate the synthesis of effective angiotensin antagonists. The hemodynamic changes produced by angiotensin have received much recent attention. Both short‐term arullong‐term measurements of its effects on the systemic and pulmonary circulation have been made, as well as measurements of its effects on specific vascular beds and organs. The latter have included capillary and smoll arteriolar and venous beds, the carotid sinus, the heart, muscle versus splanchnic and renal vascular beds, and the adrenal gland. The effect of angiotensin on aldostemne secretion and the changed amounts of these hormones in various types of hypertension are receiving much current attention. The results of these studies may prOVide partial answers to the problem of the interaction of the various systems controlling blood pressure included in the mosaic theory of hypertension.