SummaryThe results suggest an important role of the renin-angiotensin system in the forms of arterial hypertension characterized by a state of vasoconstriction. The absence of correlation between the reduction of renin secretion and the lowering of blood pressure under the action of the betablocking drug can at least partially be explained by changes in cardiac output (other actions e.g. lower of the orthosympa-thetic tone at the level of the central nervous system, cannot be exclued).