Abstract

The liver metabolism of hexobarbital was studied in male rats subjected to stress (restraint and thermal stimuli). Hexobarbital metabolism did not change two hours after stress but was decreased 48 hours after the onset of stress. This effect of stress was noted in adrenalectomized but not in hypophysectomized rats. Simulation of hormonal conditions in stress by corticosterone or somatotropin injections showed no depression of hexobarbital metabolism in rats with high corticosterone levels. However, the liver metabolism of hexobarbital decreased 48 hours after administration of somatotropin to intact, corticosteronetreated, adrenalectomized or hypophysectomized rats. We propose that somatotropin is a pituitary hormone involved in the stress-mediated depression of hexobarbital metabolism.