Nitrogen excretion and the uricolytic enzymatic system in the nephridia and hepatopancreas of the snail Xeropicta arenosa

Abstract

The quantitative and qualitative examination of the uricolytic system in the nephridia and hepatopancreas of the terrestrial snail Xeropicta arenosa showed the presence of all the metabolites of uric acid catabolism, and examination of the metabolites of the uricolytic system in the snails waste products revealed that uric acid was the main nitrogenous waste product excreted. Correlation of excretion capability with the age of the snails revealed that (i) uric acid concentration was nine times higher in the waste products of the juveniles than in those of the old snails, (ii) urea was detectable only in waste products of old snails, (iii) traces of ammonia were detected in the waste products of snails of both ages, and (iv) the amount of allantoin present in the old snails' nephridia and heart was significantly higher than in those of the juveniles. On the other hand, all snails, regardless of age, stored most uric in the nephridia. Uric acid nitrogen represented 1% of the total nitrogen in the nephridia. Data from chemical analysis were confirmed by radiochemical analysis and showed the existence of the complete sequence of uricolytic catabolites in the snails' waste products and nephridia.