Responses of the pressor and depressor regulatory systems to high sodium intake in borderline arterial hypertension

: A total of 25 healthy individuals and 48 borderline hypertensives aged 22-56 years were examined. The healthy subjects having a salt load showed elevated blood histamine concentrations and an unchanged vascular response to histamine, and reduced plasma renin activity. The patients having a salt load displayed high histamine levels, sharply decreased vascular response to histamine, and undepressed plasma renin activity. It is concluded that the pressor mechanisms responsible for controlling vascular tone are more active than the depressor ones during the salt load in patients with borderline hypertension. The humoral response of the patients to a salt load was impaired with elevated plasma cortisol concentrations, which was not followed by sodium retention in the body.