Endotoxin lethality and tryptophan pyrrolase induction in cold-exposed mice

¹ Department of Biology, Bryn Mawr College, Bryn Mawr, Pennsylvania

Mice singly housed and exposed to 5 C are almost as responsive as animals at 25 C in carrying out glyconeogenesis following a single injection of cortisone. An ld₅₀ of endotoxin lowers liver glycogen about equally in mice housed at each of the two temperatures but the dose for mice at 5 C is 1/100 the dose at 25 C. Cortisone given concurrently with the endotoxin prevents glycogen depletion in mice at 25 C but not in those housed at 5 C, except, possibly, at certain critical doses. Cortisone also fails to induce an increase in liver tryptophan pyrrolase activity in cold-exposed mice, in contrast to those maintained at room temperature, and this failure cannot be ascribed to any alteration in hematin level, the cofactor for the enzyme. These findings are considered as evidence for an impaired capacity for protein (enzyme) synthesis in normothermic animals during acute exposure to cold.

Key Words: effect of cold on endointoxication • effect of cold on enzyme induction

Submitted on March 9, 1964