Renal blood flow after stimulation of p-aminohippurate transport.

Repeated administration of cyclopenthiazide enhances renal PAH excretion in rats. In the 1st hr after an acute PAH load the renal excretion of PAH is doubled compared with controls. Haemodynamic measurements show that this acute PAH load is related to an increase in renal blood flow, in particular to a distinct increase in blood flow in the renal cortex. This increase in renal blood flow and in intrarenal blood distribution is higher than in stimulated rats. The increase in renal excretion of PAH is stimulated rats is not connected with an increase in renal blood flow. After an acute PAH load an additional increase in renal blood flow in stimulated rats could not be observed as compared with non stimulated control rats.