Effect of Thyroid Hormones on Distension-Induced Gastric Acid and Pepsin Secretions in Rats

Abstract

Thyroid hormones are known to influence acid and pepsin secretion, though the exact mechanism is not fully understood. In this study, distension-stimulated acid and pepsin secretions in hypo- and hyperthyroid rats were compared with controls. Each group consisted of 8 N-mari rats of both sexes, weighing 246.6+/-9.2 g. Hypo- and hyperthyroid states were induced by administration of methimazole (500 mg/L H2O) and thyroxin (200 microg/L H2O) respectively, in drinking water. All animals were deprived of food, but not of water 24 hours before the experiments. After anesthetization with sodium thiopental (50 mg/kg body weight, ip), tracheotomy and laparatomy, gastric secretions were collected through a cannula introduced via the duodenum. Gastric distension was induced by the injection of Ringer solution in stomach (1.5 cm(3)/100 g body weight). Acid secretions, which were measured by automatic titrator in the hypothyroid, hyperthyroid and control groups were 8+/-0.2, 14.6+/-1.9 and 10.2+/-0.1 micromol/15 min, respectively. Pepsin secretions were 4.4+/-0.5, 9.09+/-0.4 and 6.1+/-0.1 mg/15 min. in respective groups. There were statistically significant differences in both series between control and the other two groups. The results from the measurements of thyroid-stimulating hormones and T4 hormones showed that increased or decreased thyroid function can significantly affect gastric distension-induced acid and pepsin secretion.