Gastric Mucosa after Irradiation. Ii. Inhibition of Gastrin-Stimulated Acid Secretion (PH 3.0) IN Relation to Translocase Activity

摘要

Immediately after a dose of 240R, whole body X-irradiation, spontaneous (non-stimulated) acid secretion was inhibited. The inhibition was transient and acid secretion resumed promptly after injection of gastrin as the semipurified hormone. During the stimulation phase, a subsequent irradiation dose of 3000 R caused inhibition which was also transient, since secretion resumed immediately on cessation of the irradiation. Under standard conditions of gastrin stimulation, a dose dependent reduction in acid secretion could be demonstrated, using dose levels of 600 R and 1200 R, given 4 hours earlier. This dose dependent inhibition could be detected only when acid secretion was maximally stimulated by gastrin. The Skou transport enzyme was isolated, also, from gastric mucosa, under identical conditions of irradiation and gastrin treatment. Activity of transport enzyme, in other studies, was found to be radiation sensitive in this dose range, but its activity under present conditions was remarkably constant and unaffected by gastrin or irradiation treatments. Present findings indicated that irradiation doses of 600 to 1200 R caused negligible functional damage to the acid secretory mechanism, as in parietal cells. However, inhibition of nerve activity, necessary for maintenance of high acid secretion rates, evidently did occur. (Author)