Response of submandibular gland of the rat to nutritional zinc deficiency.

Studies in several laboratories have shown that nutritional Zn deficiency in the rat causes a reduction in the activity of certain Zn-dependent enzymes in kidney, intestine, pancreas, etc. The present report deals with the effects of Zn-deficiency on submandibular gland of the rat. For the sake of comparison with previous studies, some assays on pancreas were included. Protein content, DNA, acid phosphatase, and acid protease activities were not affected in submandibular gland. Lactate dehydrogenase was unaffected in submandibular gland and showed increased activity in pancreas. Malate dehydrogenase was significantly decreased in both organs, the decrease being more marked in submandibular gland. Alkaline phosphatase activity in submandibular glands of control rats was about 10-fold higher than in pancreas. In the zinc-deficient rats, alkaline phosphatase was reduced to 59% of controls in the submandibular glands and to about 75% in pancreas. It is known from histochemical studies that in the submandibular gland this enzyme is confined to the myoepithelial cells. Recent studies attribute to salivary glands a role in the etiology of taste disturbances seen in clinical states of zinc deficiency. It is proposed that functional impairment of the myoepithelial cells might contribute to the disturbance of taste.