EFFECTS OF LOW TEMPERATURE ON MAGNESIUM CONTENT OF BLOOD, BODY FLUIDS AND TISSUES OF GOLDFISH AND TURTLE

Abstract

The source of increased serum Mg under conditions of hypothermia was investigated in body fluids and tissues of goldfish Carassius auratus and turtle Chrysemys elegans. The azo dye titan yellow was used for all estimations of Mg. The actual amt. of Mg was evaluated on basis of total tissue present as well as blood and body fluid volumes for control and cold-treated animals. Goldfish exposed to freezing temp. showed a 159% rise in serum Mg. Anoxia coincident with cold increased serum Mg 627%. This Mg came very largely from nucleated red blood corpuscles. These increases occurred in the face of marked hemodilution as measured by hematocrit. Conditions attendant on these observations are discussed. The turtle on exposure to temp. of 2 [plus or minus] 3[degree]C showed a 58% rise in serum Mg and a 70.7% increase in perivisceral fluid Mg. These increases were not reflected in the dialyzable fractions. Pericardial fluid Mg did not change significantly. In contrast to goldfish, hema-tocrit of turtle did not change, nor were the nucleated red corpuscles involved in Mg exchange. A 55% loss of Mg was observed in muscle and 60.3% loss from skin. Liver Mg remained unchanged. Hypothermia increased water content of turtle muscle 2.5% and of skin 3.7%.