Five years' experience with gamma-L-glutamyl-L-dopa: a relatively renally specific dopaminergic prodrug in man.

1. Over the last 5 years we have given intravenous gludopa in man and established its effects on the kidney. 2. At doses of 12.5 to 100 micrograms kg-1 min-1 it is natriuretic and also tends to increase renal blood flow and glomerular filtration. Despite the natriuresis, plasma renin activity is depressed and this effect is blocked by domperidone. The receptors for the tubular natriuretic effect are blocked by d-sulpiride. 3. Four-hour infusions in man do not lower blood pressure; 10-h infusions lower blood pressure and increase pulse rate. 4. The oral bioavailability of gludopa is only 1 to 2% and this rules out the dipeptide as an effective dopaminergic prodrug.