STUDIES ON THE EXPERIMENTAL ALTERATION OF WATER AND ELECTROLYTE COMPOSITION OF THE EEL (ANGUILLA ANGUILLA L.)

Abstract

SUMMARY The distribution of water, electrolyte composition (Na, K, Ca, Mg, PO4, Cl) and extracellular fluid volume of eels (Anguilla anguilla L.) were investigated under different experimental conditions. Adrenalectomy of the freshwater eel was followed by an increase in body weight, a fall in the amount and concentration of sodium in serum and muscle and a shift of water into the cells. The concentration of serum potassium remained within the normal range. Adrenalectomy of the sea-water eel was followed by a decrease in body weight and an increase in the concentration of extra- and intracellular sodium. The concentration of serum calcium also increased, that of potassium remained within the normal range but the actual content diminished. Removal of the corpuscles of Stannius from the freshwater eel gave some effects similar to adrenalectomy. There was, however, no significant increase in body weight but the concentrations of serum potassium and calcium rose. Removal of the corpuscles from the sea-water eel brought about changes similar to, but less pronounced than those after adrenalectomy. The results of the injection of mammalian corticotrophin, cortisol, aldosterone and anti-aldosterone compounds are given. They are discussed in the light of the possible roles of the adrenal cortex and the corpuscles of Stannius in the maintenance of homeostasis of the eel in different environments.