Histochemical localization of glycoconjugates in the developing endolymphatic sac and vestibular end organs of the mouse.

The distribution of glycoconjugates in the endolymphatic sac (ES) and vestibular end organs from the 12th gestational day (GD) in the developing mouse to the 6th day after birth was analyzed using six biotinylated lectins: wheat germ agglutinin (WGA), Abrus precatorius agglutinin (APA), Ulex europaeus agglutinin I (UEA-I), Ricinus communis agglutinin 120 (RCA120), Helix pomatia agglutinin (HPA), concanavalin A (conA). In the 13th and 15th GD sections, the luminal contents in the fetal ES were strongly labelled with lectins, while only a small amount of substance in the ES was labelled with lectins after the 17th GD. In the 13th GD sections, before the cupula and otoconia were formed, the fetal ES started to produce glycoconjugates labelled with WGA, APA, RCA120 and ConA. In the 17th GD sections, the immature cupula and otoconia were strongly labelled with WGA, APA and RCA120. Sugar residues stained by lectins detected in the substance of the fetal ES were the same as those found in the immature cupula and otoconia. HPA only stained the ES epithelium around the 13th and 15th GD. The fetal ES may interact with the formation of the cupula and otoconia, especially in the early stage during evolution and that HPA-reactive glycoconjugates may be related to the intracellular elements of the ES epithelium only during a well-defined phase of development.