Effect of the dopamine agonist bromocriptine on blood pressure, catecholamines and renin activity in acromegalics at rest, following exercise and during insulin induced hypoglycemia.

Seven acromegalic patients were given bromocriptine, starting with 1.25 mg/day, then gradually increased to 20 mg daily, which dosage was continued for 3--9 weeks. Treatment with bromocriptine resulted in a significant fall of systolic and diastolic blood pressure in supine and upright position accompanied by a marked reduction in plasma and urinary noradrenaline but without effect on adrenaline. Plasma renin activity fell during institution of bromocriptine and remained significantly lower during prolonged treatment. Urinary aldosterone showed no significant changes during medication. The plasma noradrenaline response to physical exercise was reduced by bromocriptine treatment, whereas the adrenaline response was unaltered. The plasma catecholamine response to hypoglycemia was not statistically different during bromocriptine as compared to before medication.