Histochemical characterization of the naso-labial glands of two species of ruminants (Ovis aries and Bos taurus).

: The bovine and ovine naso-labial glands have been examined. In both species these glands are multilobular tubulo-acinar, but the cells of secretory units display differences regarding nuclear shape and location, RER arrangement and secretion pattern. In this paper, histochemical characterization of naso-labial gland secretion was performed using the periodic acid Schiff reaction (PAS), the Alcian blue staining (AB) at pH's ranging between 1.7 and 2.5, the Alcian blue-high iron diamine (HID-AB) method, an immunohistochemical staining for muramidase at the light microscopic level and the periodic acid-thiocarbohydrazide-silver proteinate (PA-TCH-SP) technique at the electron microscopic level. In bovines the secretion is composed of glycoproteins, which are reactive to PAS, but not to Alcian blue staining. In ovines, a large quantity of acidic polysaccharides in association with a small quantity of sulfomucins has been found. Ultrastructural and cytochemical observations show that secretory granules do not have a homogeneous structure. They appear to be formed of a meshwork stained positively with the PA-TCH-SP method immersed in a light background. The particular morphological features of the naso-labial glands and their histochemical features suggest that these glands can be classified as sero-mucous in bovines and mucous in ovines.