Lectin staining patterns in secretory granules of rat parotid gland acinar cell of untreated and isoproterenol-injected animals were examined by electron microscopy. We used four lectin-gold complexes: Ulex europaeus agglutinin I (UEA-I), Helix pomatia agglutinin (HPA), wheat germ agglutinin (WGA), Glycine max agglutinin (SBA). Specimens were low temperature embedded in the hydrophilic Lowicryl K4M resin. The normal acinar cells produced glycoconjugates which were positive for all of the lectins used and with a characteristic topographic distribution in relation to the morphological type of granule. The cells of isoproterenol-treated rat showed marked ultrastructural changes in the size and structure of granules; significant changes in lectin binding sites in the granules were also observed.