HISTOCHEMICAL AND BIOCHEMICAL DETERMINATION OF CALCIUM IN SALIVARY-GLANDS OF CAT

Although feline salivary glands have been used in investigations on se cretion and microlithiasis and both processes involve calcium, nothing is known about its distribution in these glands. Therefore we have de monstrated the presence of calcium by a histochemical technique using glyoxal bis(2-hydroxyanil) and a biochemical technique using dry ashin g. The histochemical technique stained serous acinar cells weakly and rarely found mucous acinar cells strongly in the parotid gland, mucous acinar cells moderately to strongly and serous acinar cells weakly in the sublingual gland, and central and demilunar acinar cells moderate ly to strongly in the submandibular gland. The biochemical technique r evealed less calcium in the parotid than in the submandibular and subl ingual glands. Both techniques revealed a decrease of calcium in subma ndibular and sublingual glands following parasympathetic stimulation. The histochemical distribution of calcium, which corresponds to that o f acinar secretory glycoprotein, and the loss of calcium following par asympathetic stimulation, which causes release of secretory granules, indicate the presence of calcium in secretory granules. The concentrat ion of calcium in the different types of acinar cell corresponds to th e acidity of the secretory glycoprotein and suggests that calcium is p resent as a cationic shield to allow the condensation of polyionic gly coprotein in secretory granules.