Effect of Thallium Acetate on the Basal Metabolism of Rats

Abstract

Leigheb 1 and others have observed that the administration of thallium acetate to rats and guinea-pigs produces extensive degenerative changes in the thyroid gland. In view of these observations, the following experiments were undertaken to study the basal metabolism of animals treated with the drug.

Four white rats of the same breed and of approximately the same age were injected subcutaneously with thallium acetate in aqueous solution. Three of the animals received 12 mg. of the thallium salt per kilo of body weight and one, 8 mg. per kilo. Before the administration of the thallium acetate, 4 observations were made on the basal metabolism of each animal at intervals of 3 or 4 days. After the administration of the drug, the basal metabolism was studied at similar intervals, until the basal metabolic rate returned to normal. The technic used for determining the basal metabolism was that described by Wu and Chen. 2 For each experiment there were from 6 to 8 determinations. The average of only those determinations (usually 3) taken at the time the animal was quiet was used as the final result of the experiment.

All of the rats showed diminution of their basal metabolic rates, in parallel with which, defluvium of hair on the back and less briskness of the animals were noticed. In the 3 rats injected with 12 mg. of thallium acetate per kilo of body weight, the basal rates began to diminish from the 8th to the 15th day after the administration of the thallium salt. One of the animals died at the end of the experiment on the 21st day after the injection of the drug, at which time the basal metabolic rate was at its lowest.