Serum Gastrin, Motilin and Secretin in Treated and Untreated Hyperthyroidism

To study the gastrointestinal hormones involved in hyperthyroidism and the interrelationship with the thyroid hormones, the preprandial serum concentrations of gastrin, motilin and secretin were measured by radioimmunoassay in 33 normal subjects and in 104 patients before and after treatment. The following results were obtained. 1) Serum gastrin concentrations in hyperthyroid patients were significantly higher than that of the control, and when the patients reached euthyroidism or hypothyroidism after treatment, the gastrin concentrations in the serum decreased to the normal level. There was a positive correlation between thyroid hormones and serum gastrin. 2) The changes in serum motilin concentrations in hyperthyroidism before and after treatment did not show any significant differences from that of the control. There was a slightly negative relationship between motilin and gastrin and also between T4 and motilin. 3) The mean serum secretin level rose significantly in hypothyroid patients after treatment for hyperthyroidism, but there was no individual correlation between serum secretin and thyroid hormone.