Pteridine diuretics as biopterin antagonists

Abstract A series of pteridines having varying degrees of diuretic activity were tested for their effects on the growth of the pteridine-requiring flagellate, Crithidia fasciculata . Inhibition of growth was correlated with diuretic activity insofar as compounds devoid of diuretic effects were uninhibitory and active inhibitors were also good to fair diuretics. Reversal of the growth inhibition was obtained with 2-amino-4-hydroxy-6- l - erythro -1',2',3'-trihydroxy-propylpteridine in a competitive manner, while folate showed a logarithmic relationship to the drug concentration for 50 per cent inhibition.