[The circadian rhythm of the formation of stress stomach ulcers in rats].

Areas of stress-induced gastric ulceration vary parallels with changes of corticosterone levels. The ulceration was greater in the morning during low basal corticosterone level than in the evening during high one. Adrenalectomy ceased the circadian basal rhythm of corticosterone and the rhythm of stress-induced ulceration. The decrease of ulceration in the evening seems to indicate an increase of the body adaptability resulting from the circadian corticosterone increase.