Uricotely
In zoology, uricotely is the excretion of toxic nitrogen compounds, especially ammonia , in the form of the much less toxic uric acid in the urine . Such nitrogen compounds are created when nucleotides and proteins are broken down . While some of the resulting compounds are recycled, excess compounds must be excreted in the urine.
Typical representatives with uricotelia are reptiles , birds , insects and terrestrial snails ; but also a few wüstenbewohnende amphibians and maki frogs are uricotel. The advantage of this form of N excretion is that uric acid is not very soluble in water and therefore only small amounts of water are required for excretion. Uric acid can be released as an almost anhydrous paste. A disadvantage of uricotely is the high energy expenditure in the synthesis of uric acid from ammonia .
In mammals , the ammonia produced when amino acids are broken down is released as urea ( ureotelia ). With the exception of primates and some domestic dogs (especially dalmatians ) , the uric acid produced during the breakdown of purine bases is converted into allantoin via the uricase enzyme . Primates and these dogs therefore also have a certain amount of uric acid in their urine.
Individual evidence
- ^ N Karmi, EA Brown, SS Hughes, B. McLaughlin, CS Mellersh, V. Biourge, DL Bannasch: Estimated Frequency of the Canine Hyperuricosuria Mutation in Different Dog Breeds . In: Journal of Veterinary Internal Medicine . tape 24 , no. 6 , 2010, p. 1337–1342 , doi : 10.1111 / j.1939-1676.2010.0631.x .