Selye has reviewed many types of stresses which produce gastric ulceration in experimental animals. Stress situations have been reported to produce gastrointestinal lesions and it has been known that several factors are involved in the production of the signs of stress: age, the presence of the adrenals and hypophysis, and the state of the nutrition.
Ivy reported the higher incidence of gastric ulcers in cachectic dogs than in normal ones. Siebert and Mollogy reported that the partial starvation was a cause of ulcer. Daldorf and Kellogy reported a higher incidence of ulcer in thiamine deficient rat, while others reported low protein diet as a cause of the gastric ulcer. Deficiencies of other nutrients such as riboflavin, cystine. choline, pyridoxine, tocopherol, pantothenic acid, vitamin A and calcium have also been reported as factors which produce gastric lesions in experimental animals.
Riboflavin is known as an essential factor for growth and its deficiency results in cessation of growth and in prolonging tissue repair, eczematous dermatitis and conjunctivitis and so on. Riboflavin is also essential as an integral constituent of gastrointestinal tissue and its normal function. It would appear that stomach lesions in rats may occur in deficiency of riboflavin.
However, no report is available concerning influence of stress to the gastric mucosa of riboflavin deficient animals.
The present study was undertaken to investigate the effects of ACTH or of shaking stress on the gastric mucosa of riboflavin deficient rats.
Albino male rats weighing 75 to 175 gm were devided into two groups. The experimental group was on a riboflavin deficient diet and the control group was on a regular diet which contains all nutrients necessary to rats.
Four experiments were performed. The first experiment was undertaken to study the effect of ACTH on the gastric mucosa of riboflavin deficient rats. The second to fourth experiments were undertaken to study the effect of "shaking stress on the gastric mucosa of the riboflavin deficient rats.
(1) The growth.
In all experiments the riboflavin deficient group of rats showed cessation of growth while the control group of animals were growing continuously as normal.
(2) The excretion of urinary 17-ketosteroid in 24 hours urine.
There was no difference in urinary excretion of 1 f-ketosteroid between riboflavin deficient group and the control group. Following the shaking stress, the 17-ketosteroid has increased excretion in both groups. but more in deficient groups than that of controls.
(3) The excretion of uropepsin in 24 hours urine.
There was no difference in uropepsin excretion between two groups. Following the shaking stress, in riboflavin deficient groups increase in uropepsin excretion was shown while in the control group no appreciable increasing was noticed.
(4) The excretion of urinary N'-methylnicotinamide and nicotinic acid in 24 hours urine.
Markedly less excretion of N'-methylnicotinamide and nicotinic acid was observed in riboflavin deficient group compared with that in control group. Neither administration of ACTH nor shaking stress caused any change in excretion both of them.
(5) The excretion of xanthurenic acid and anthranilic acid in urine.
After loading with tryptophan increased excretion of xanthurenic acid and anthranilic acid in riboflavin deficient group was observed. These results indicated that riboflavin deficiency inhibits the normal catabolism of tryptophan.
(6) The change of gastric mucosa.
(A) No gastric mucosal change was observed in riboflavin deficient rats.
(B) After injection of ACTH intramuscularly (7 units/rat/day/ for 5 days), bleeding, congestion, erosion and brownish superficial ulcers situated in the glandular portion of the stomach were observed.
(C) The mechanical shaking with a frequency of 180, 200 or 240 per minute for 3 hours daily for a period of three, four or twelve days were given to both groups.
In both groups, bleeding, congestion, erosion and superficial ulcers were observed. The big and deep ulcers were also observed in the forestomach. These changes were more severe in young and riboflavin deficient rats, and in rats given the mechanical shaking of intense frequency.