Adrenocortical response to single and repeated doses of chloroform in rats.

The influence of single and repeated doses of chloroform on the adrenocortical function was studied in young male albino rats. One day after oral administration of a single dose of 1.5 g chloroform/kg body weight, adrenal hypertrophy developed and persisted for at least 12 days. The adrenal cholesterol content started to drop 3 h after the application, remained low for 1 day, then increased and remained elevated during the next 12 days. The plasma corticosterone content increased 15 min after the treatment and remained high during the next 4 h; 6 h after the treatment, when the anesthetic effects of CHCl3 had disappeared, it decreased somewhat; after 12 h it increased again, and the peak value was observed after 1 day. This was followed by a gradual drop, and after 8 days it reached the normal level. A second dose, administered 4 or 8 days after the first one, was still capable of stimulating the adrenocortical function. This was evidenced 24 and 48 h after the second dose. The response, however, was smaller than that observed after a single dose of the same stressor. The influence of a single dose of chloroform on corticosterone decay in the circulation 1 and 9 days after treatment, was tested in adrenalectomized rats injected with non-radioactive corticosterone, and in intact rats injected with 1,2-3H-corticosterone. Results for the adrenalectomized animals were inconclusive, whereas those for the intact ones proved that the treated animals metabolized corticosterone as well as the controls did.