Physiological Adjustments in Chloride Balance of the Goldfish

Abstract

Using 80 goldfish, 164 detns. of the chlorides in the water around each fish over periods from 20 min. to 117 hrs. were made. In the first 20 min. there was an appreciable loss of chloride ion into the water. This loss continued at a decreasing rate for 4-6 hrs., at which time absorption of chlorides was begun. All chloride lost was regained at 24 hrs. Even additional chloride was absorbed. In 3 cases, NaCl was added to the water and the absorptive process followed for 117 hrs. The chloride uptake by the fish continued through 17 hrs., leveling off at 96 hrs. The chloride exchange was done via the gills. In another expt., there was a significant difference in absorption between fish injected intraperitoneally with 50 mg. of chloride ion and those receiving distilled water; there was no significant difference between the absorption of chloride by uninjected controls and the distilled water group. Excretion of chloride ion was reduced in fish receiving the distilled water injn. Excitation by handling can initiate changes in the absorptive mechanism. Once absorption is begun, reducing the chloride concn. of the body retards excretion of the ion but it does not accelerate absorption. Increasing the chloride concn. of the body fluids retards absorption but it does not increase the rate of excretion.