Seasonal Variation in blood plasma sodium and potassium concentrations in the lizard Agama nupta (Agamidae)

Seasonal changes in the concentrations of Na and K ions in the blood of Agama nupta in summer are reported from a population in Iran. These lizards do not have access to free water and acquire all their required water from their diet of insects. The hypematraemia and hyperkalaemia reported here may be the result of chronic dehydration but could also result from the accumulation of ions in the extracellular fluid, as has been shown in other species of lizards. In contrast to herbivorous species of lizards, A. nupta, which is insectivorous, does not appear to have an active nasal salt gland for excreting sodium and potassium as salt-loading in the laboratory failed to evince any secretions.