AJP - Renal Physiology, Vol 250, Issue 6 975-F979, Copyright © 1986 by American Physiological Society
Handling of dopamine and dopamine sulfate by isolated perfused rat kidney
N. T. Buu, J. Duhaime and O. Kuchel
The possible contribution of circulating dopamine sulfate to urinary free
dopamine and the synthesis of norepinephrine by the renal nerves were
examined in the isolated perfused rat kidney. Perfusion of the kidney with
dopamine sulfate did not yield significant amounts of free dopamine
indicating that, unlike L-dopa, dopamine sulfate is not a good source of
urinary free dopamine. The excretion of dopamine sulfate was slower than or
comparable with that of free dopamine, suggesting that sulfoconjugation is
not a mechanism to facilitate the excretion of free dopamine. Unlike free
dopamine, dopamine sulfate was not metabolized by renal
catechol-O-methyltransferase or monoamine oxidase. Perfusion of L-dopa and
free dopamine led to the generation of norepinephrine in the kidney. This
synthesis was abolished when the kidney was denervated, suggesting that the
renal nerves were the main sites of the norepinephrine synthesis. Both
norepinephrine and dopamine were rapidly metabolized by
catechol-O-methyltransferase and monoamine oxidase, but renal
phenolsulfotransferase appeared to have no action on the catecholamines.
