[Effect of sub-pressor doses of dopamine on renin secretion in the anesthetized dog]

The effects of dopamine, its precursor L-dopa, and the dopaminergic agonist bromocriptine (BEC), on plasma renin activity (PRA), in pentobarbital anesthetized male dogs were investigated. Infusion of dopamine at a dose which did not change blood pressure ( 4 ug/kg/min) had no effect on the secretion of renin, nor did it produce modifications in the PRA response to furosemide (10 mg i.v.). L-dopa, in single dose of 500 mg (p.o), significantly augmented PRA two hours after administration, and the renin values remained elevated throughout the observation period of 120 minutes. However, BEC (2.5 mg p.o.) produced no changes in PRA during this time period. We conclude that at the dose utilized, dopamine apparently has no influence on the secretion of renin, and does not modify the increase in PRA provoked by diuretic. It is possible that the L-dopa induced augmentation in PRA is due to stimulation of the juxtaglomerular cells, by the noradrenaline formed in peripheral tissues from administered L-dopa.