Changes

The primary catabolic end product of protein, non-protein nitrogen and purines depends upon a reptile’s natural environment. Terrestrial reptiles excrete uric acid as the primary nitrogenous waste product (i.e. they are uricotelic). Uric acid is synthesised in the liver and excreted by renal tubular secretion.  The blood level is therefore largely independent of urine flow rate (and is therefore not a sensitive indicator of dehydration in reptiles or birds). Both animal and environmental factors influence uric acid levels. The normal blood uric acid value for most reptiles is 0 to 600 µmol/l.  

The primary catabolic end product of protein, non-protein nitrogen and purines depends upon a reptile’s natural environment. Terrestrial reptiles excrete uric acid as the primary nitrogenous waste product (i.e. they are uricotelic). Uric acid is synthesised in the liver and excreted by renal tubular secretion.  The blood level is therefore largely independent of urine flow rate (and is therefore not a sensitive indicator of dehydration in reptiles or birds). Both animal and environmental factors influence uric acid levels. The normal blood uric acid value for most reptiles is 0 to 600 µmol/l.  

===Hyperuricaemia===

===Hyperuricaemia===

Plasma levels of uric acid increase with [[Lizard and Snake Renal Disease|renal disease]] but this is neither a sensitive indicator of renal dysfunction, nor a specific indicator since physiological increases are common. Physiological high levels are seen in several species during [[Hibernation|hibernation]], probably due to decreased tubular function at low temperatures. Healthy snakes should be resampled after a fast if a high uric acid level is seen. Increased uric acid levels are seen with gout and renal failure. The loss of about two thirds of the renal functional mass is necessary before uric acid increases and therefore rises late in the course of renal failure. Renal failure has been associated with nephrocalcinosis (associated with high dietary levels of [[Calcium|calcium]] or hypervitaminosis D), [[Visceral gout|visceral gout]] (caused by dehydration, renal failure or toxicosis) and nephrotoxic drugs (aminoglycosides can result in significant renal tubular necrosis).

Plasma levels of uric acid increase with [[Lizard and Snake Renal Disease|renal disease]] but this is neither a sensitive indicator of renal dysfunction, nor a specific indicator since physiological increases are common. Physiological high levels are seen in several species during [[Hibernation|hibernation]], probably due to decreased tubular function at low temperatures. Healthy snakes should be resampled after a fast if a high uric acid level is seen. Increased uric acid levels are seen with gout and renal failure. The loss of about two thirds of the renal functional mass is necessary before uric acid increases and therefore rises late in the course of renal failure. Renal failure has been associated with nephrocalcinosis (associated with high dietary levels of [[Calcium - Reptiles|calcium]] or hypervitaminosis D), [[Visceral gout|visceral gout]] (caused by dehydration, renal failure or toxicosis) and nephrotoxic drugs (aminoglycosides can result in significant renal tubular necrosis).

==Calcium==

==Calcium==