Record Details

Templeton, James R;Murrish, David E;Randall, Edward M;Mugaas, John N
Salt and water balance in the desert iguana, Dipsosaurus dorsalis
Zeitschrift für Vergleichende Physiologie
Journal Article
Dipsosaurus dorsalis
Desert iguanas deprived of food and water for about ten days apparently utilized intracellular fluid as well as stored lympli from lateral and gular storage sacs. As they rehydrated on a lettuce diet, the K/Na ratio of total excreta remained depressed allowing K and water to replace the lost intracellular fluid. Both urine and nasal fluid removed about equal amounts of sodium, but the nasal fluid contained far more K. As rehydration continued the urine gradually became the predominant excretory route removing cations as urates and dissolved ions. The fecal K/Na remained at unity even though dietary K/Na approximated seven suggesting that the gut-cloaca can regulate fecal cation exchange. At full hydration, salt and water balance was restored. The lizards' excretory K/Na equaled that of the diet. Water was treated as a waste, and relatively great quantities were removed in urine which now contained most of the lost cations. The nasal salt gland continued to excrete but it is ill-equipped to remove the excess water. Aldosterone lack may act to depress the K/Na excretory ratios of dehydrated and rehydrating lizards.