Preventive effect of some substances on experimental oxalic calculogenesis in the frog.

Rana esculenta tadpoles that are fed spinach develop an oxalic calculogenesis. The addition of cholestyramine, orthophosphate, citrate, allopurinol and tungstate to the tank water prevented calculi formation while succinimide, magnesium oxide, hydrochlorothiazide and tetracycline were ineffective. Methylene blue proved lethal to tadpoles, and its anti-lithogenic activity could not be assessed. These findings, except for the non-effectiveness of magnesium oxide, are in agreement with both the theoretical expectations and the results obtained in other experimental models. Experimental frog calculogenesis seems to be a simple and valid method for evaluating anti-lithogenic activity.