Electrolyte excretion by the nasal gland of an herbivorous Saharan lizard, Uromastix acanthinurus (Agamidae). Effects of single NaCl and KCl loads

Abstract

The excretory capacity and adaptability of the nasal salt gland of the Saharan lizard Uromastix acanthinurus have been investigated using single saline loads. The salt gland complements the role of the cloaca when the lizards are in water and electrolyte balance, but appears to have a greater importance when they are subjected to large excesses of food or to dehydration. When stimulated by saline loads (NaCl or KCl), the nasal gland can eliminate the major part of the electrolytes injected, the excretion varying in quantity and quality according to the loading. Variation in the K+ /Na+ ratio of nasal secretions thus allows the lizards to adapt to natural variations (seasonal or geographic) in their plant food. In this herbivorous species, as in other terrestrial lizards, the nasal gland appears to be well adapted for the elimination of K+ and Cl− ions.