Persistently Increased Gastrin and Decreased Pepsinogen Concentrations in Serum from Some Patients with Graves' Disease of Triiodothyronine-Predominant Type and Common Type

This study aimed to investigate the cause of persistently increased serum gastrin concentration seen in some Graves' disease patients even when euthyroid during antithyroid drug treatment. The subjects studied consisted of three groups: 33 patients with a common-type of Graves' disease, 14 with triiodothyronine (T₃)-predominant Graves' disease (characterized from previous studies as having potent immunologic abnormalities including greater concentrations of thyroid-stimulating antibodies together with larger goiter size), and a group of 20 normal subjects. Fasting serum gastrin concentrations in common Graves' disease patients were significantly higher than those of normal subjects (58.4 ± 38.9 pmol/L vs. 37.8 ± 18.9 pmol/L [mean ± SD], p < 0.05). The serum gastrin concentrations were even greater in T₃-predominant Graves' disease patients than common Graves' disease patients (162.9 ± 224.0 pmol/L vs. 58.4 ± 38.9 pmol/L, p <.05). Serum pepsinogen I (PGI) concentrations were significantly lower in the T₃-predominant patient group than the common Graves' group (24.0 ± 12.9 ng/mL vs. 39.7 ± 19.6 ng/mL, p <.05). Serum ratios of PG I to PG II were significantly lower in the T₃-predominant Graves' disease patients than normal subjects (3.59 ± 2.66 vs. 5.97 ± 1.56, p <.01). The ratios also had a significant (p <.05) inverse correlation with serum gastrin concentrations in T₃-predominant Graves' disease patients. The results suggest that autoimmune gastritis is associated with Graves' disease, particularly in patients with potent thyroid-autoimmunity.