CORRELATED HISTOCHEMICAL STAINING AND S35O4= LABELING OF SALIVARY GLAND MUCOSUBSTANCES

Correlated histochemical and autoradiographic studies were conducted on rat, rabbit, cat and dog salivary glands. Mucous acini of rat minor sublingual (SL) rabbit SL and cat posterior SL and submandibular (SM) glands were stained by Alcian Blue at pH 1.0, aldehyde fuchsin or the high iron diamine technique. The distribution of cells with this type of basophilia corresponded with that of cells shown autoradiographically to incorporate S 35 O 4 = and accordingly to contain sulfomucin. The lack of periodic acid-Schiff and alcohol-resistant metachromasia at pH 0.5 of rabbit SL mucin resembles connective tissue mucopolysaccharide. Some mucous acini of the dog posterior SL gland incorporate S 35 -sulfate and the distribution of isotope-labeled acini correlates with that of acini showing histochemical staining indicative of sulfomucin. The remainder of mucous acini in this gland do not show uptake of radiosulfate, but have alcianophilia that is reduced by sialidase digestion. All of the mucous acini of dog SM gland show correspondence of staining for sulfomucin with S 35 O 4 – , incorporation. The seromucous demilunes of this gland manifest sialidase-labile alcianophilia. The staining of sulfomucin and S 35 labeling in each of the salivary glands studied are eliminated by a 4-hr methylation at 60°C.