SIALOGLYCOCONJUGATE DIMORPHISM OF THE MOUSE SUBMANDIBULAR-GLAND ACINAR-CELLS - ULTRASTRUCTURAL EVIDENCE BY LECTIN PROTEIN A-GOLD PROBES ANDSIALIDASE DIGESTION

An ultrastructural analysis of lectin receptors on the submandibular g lands from mice of both sexes was performed utilizing horseradish pero xidase-labelled lectins in conjunction with antiperoxidase antibody an d protein A-gold. Both qualitative and quantitative sex-related differ ences in terminal sugar expression within secretory granules were dete cted. Following sialidase digestion, also subterminal acceptor sugars for terminal sialic acids, proved to be differentially expressed in th e submandibular glands of males and females. Heterogeneous distributio n of sialoglycoconjugates characterized by the terminal disaccharide s ialic acid-beta-galactose was found to occur in female acinar cells. A lso DBA reactive sites indicating the presence of terminal alpha-N-ace tylgalactosamine discriminated between male and female acinar secretor y glycoconjugates. This difference was emphasized by sialidase pretrea tment that evidenced a marked occurrence of sialic acid subtended to a lpha-N-acetylgalactosamine in males in contrast to a modest presence i n females. The different sialylation patterns of acinar cell secretory products, probably related to a different expression of O- and N-link ed sialoglycoconjugates, give insight into the sexual dimorphism of th e mouse submandibular gland known until recently for the convoluted gr anular tubules.