Effect of beta-blocking agents on the increased serum gastrin levels in hyperthyroidism.

In a number of hyperthyroid patients the serum gastrin level exceeds the normal range. Administration of beta-blocking agents results in a decrease of the hypergastrinaemia. The fall in the serum gastrin levels is unrelated to the effect of beta-blocking agents on peripheral thyroxine metabolism, but is associated with a decline of the plasma cAMP levels. It is suggested that, though beta adrenergic sensitivity is one of the factors of hypergastrinaemia in hyperthyroidism, other factors may be involved in its production, too.