慢性胃炎に関する臨床的研究

(第2報) -γ-OZ効果の内分泌学的検討

抄録

γ-Oryzanol, ferulic acid ester of triterpenol extracted from rice-bran oil, has been used against autonomic instability with abdominal symtoms and climacteric complaints. Itaya et al. postulated that monoaminergic neuron system involved in the anti-gastric ulcerogenic action of this agent. In the first report, γ-oryzanol was found to decrease serum gastrin levels in patients with chronic gastritis. These observations have led me design the present study to elucidate the endocrine effects of γ-oryzanol in patients with chronic gastritis. Thirteen patients with chronic gastritis were orally given a daily dose of γ-oryzanol (300mg/day) for 4 weeks. Seven healthy volunteers constituted the control group. The results shown here were as follows :
1. Administration of y-oryzanol to patients with chronic gastritis resulted in decreased serum gastrin levels, which was approximately 75% lower than the initial value. In contrast, there was no significant change in the serum gastrin levels as a group after administration of γ-oryzanol to normal subjects.
2. Arginine (0.5g /kg, drip infusion over 30 min) -induced serum gastrin responses before and after γ-oryzanol treatment were similar.
3. No difference was observed in L-dopa (0.5g, orally) -induced gastrin response with or without γ-oryzanol. However, serum HGH response to L-dopa was significantly suppressed by γ-oryzanol.
4. γ-oryzanol failed to show discernible changes in serum levels of secretin, glucagon, catecholamines and prolactin.
5. Baseline serum cortisol levels following γ-oryzanol treatment were lower in all patients studied than the initial values without γ-oryzanol. In contrast, no significant change was observed in the control group. The cortisol response to ACTH was not altered byγ-oryzanol. Further more, the basal plasma ACTH levels appeared to be lowered by this agent.
The lowering effect of γ-oryzanol on serum gastrin level was clearly demonstrated in patients with chronic gastritis, in a sharp contrast to control subjects.This suggests an increased susceptibility of the patients to γ-oryzanol. The action of γ-oryzanol on serum gastrin level may result from an effect on the hypothalamo-pituitary-adrenal axis. In addition, the present investigation provides evidence that y-oryzanol is antidopaminergic in the serum HGH response, as reported in metoclopramide and sulpiride.