The Mechanism of the Increase in Sodium Excretion Following Dopamine Infusion

SummaryThe renal mechanism for the increased sodium excretion due to dopamine infusion was investigated. Infusion of 10 μg/kg/min of dopamine into the dog caused a mean increase in sodium excretion of 43 μeq/min. There was no change in glomerular filtration rate. Proximal tubule sodium reabsorption, as measured by tubule fluid to plasma inulin ratios and the transit time of lissamine green through the proximal tubule, was likewise unchanged. It is concluded that dopamine increases sodium excretion by a direct or indirect tubule effect at a site distal to the proximal tubule.