The Role of Calcium Ion in Methoxamine-Induced Amylase Release from Parotid Glands of Euthyroid and Hypothyroid Rats

Abstract

The change in responsiveness to α-adrenergic stimulation and to calcium ions in amylase release from parotid glands of hypothyroid rats was compared with that in euthyroid rats. Calcium depletion and addition of verapamil or W-7 in the medium caused a decrease in methoxamine-induced amylase release in both eu- and hypothyroid rats. Moreover, addition of calcium ions to Ca²⁺-free medium markedly increased the methoxamine-induced amylase release in proportion to its concentration in hypothyroid rats. These results suggest that calcium ions play an important role in methoxamine-induced amylase release from parotid glands of hypothyroid rats as well as those of the euthyroid ones.