RENAL FUNCTION IN THE EUROPEAN EEL (ANGUILLA ANGUILLA L.): CHANGES IN BLOOD PRESSURE AND RENAL FUNCTION OF THE FRESHWATER EEL TRANSFERRED TO SEA-WATER

Abstract

SUMMARY A method for the study of renal function and measurement of mean ventral and dorsal aortic blood pressure for the freshwater and seawater-adapted eel, and during transfer of the animal from fresh water to sea-water, is described. Freshwater eels have higher resting blood pressure, p-aminohippuric acid (PAH) and inulin clearance rates and urine flow than seawater eels. Urine from freshwater animals has low Na, K, Ca, Mg and Cl concentrations, while the clearance rate of inorganic phosphate exceeded that of inulin. Urine from seawater animals has high Na, Ca, Mg and Cl concentrations while that of inorganic phosphate was low. Clearance rates for Ca and Mg greatly exceeded those of inulin. During transfer from fresh water to sea-water there was an initial fluctuation in blood pressure, urine flow and PAH and inulin clearance rates which lasted about 2 hr. Thereafter these gradually declined to values observed for the seawater-adapted animal. The significance of PAH and inulin clearance rates in the study of renal function in the eel and in teleosts in general is discussed.