X-ray microanalysis of mammalian salivary glands.

X-ray microanalysis was used to study the elemental composition of major salivary glands in rat and man. The elemental composition of the acinar cells is influenced by a variety of factors. Stimulation of fluid secretion by cholinergic, alpha-adrenergic or peptidergic agonists leads to a sustained increase of the Na/K ratio. The elemental composition and ultrastructure of the acinar cells of rat submandibular gland, as well as flow rate and composition of pilocarpinestimulated submandibular saliva are significantly affected by thyroxine, but less by the synthetic glucocorticoid dexamethasone. Hypercalcemia (induced by chronic vitamin D treatment) as well as hypocalcemia (induced by calcitonin) cause accumulation of intracellular mucus in the submandibular acinar cells, with concurrent increase in the cellular calcium concentration, and a significantly decreased flow rate after pilocarpine stimulation. Several animal models have been proposed for the generalized exocrinopathy cystic fibrosis (CF), which may be caused by a defective regulation of chloride transport in epithelial cells. A potential new model is proposed: the chronically furosemide-treated rat, which shows several abnormalities in salivary gland structure and function that parallel the abnormalities found in the human disease. Another experimental model of potential interest in the study of CF is short-term treatment of experimental animals with the adenylate-cyclase inhibitor alloxan.