The distribution of sialic acid residues as well as other glycosidic
sugars has been investigated in the horse oviductal isthmus
during anoestrus, oestrus and pregnancy by means of
lectin and pre-lectin methods. Ciliated cells and non-ciliated
(secretory) cells exhibited different lectin binding profiles
that were found to change during the investigated stages.
Ciliated cells did not show any reactivity in the basal cytoplasm,
while the supra-nuclear cytoplasm displayed a few of
oligosaccharides with terminal and internal amannose (Man)
and/or aglucose (Glc) during oestrus and pregnancy and a
moderate presence of oligosaccharides terminating in afucose
(Fuc) during oestrus; cilia exhibited a more complex glycoconjugate
pattern for the presence of oligosaccharides terminating
in N-acetylgalactosamine (GalNAc), GalNAca1,3
GalNAca1,3galactose(Gal)b1,4Galb1,4N-acetylglucosamine(
GlcNAc), Fuc, sialic acid (Neu5Ac)-aGalNAc belonging
or not to the GalNAca1,3GalNAca1,3 Galb1,4 Galb1,
4GlcNAc sequence, and.aGalNAc and Neu5Aca 2,6Gal/GalNAc
increased during oestrus. Cilia displayed terminal Galb1,3
GalNAc in pregnancy, terminal aGal in anoestrus and pregnancy
and terminal or internal D-GlcNAc during anoestrus
and pregnancy, respectively. The whole cytoplasm of non-ciliated
cells showed oligosaccharides terminating with
aGalNAc, Neu5Aca2,6Gal/GalNAc, Neu5Ac GalNAca
1,3GalNAca1,3Galb1,4Galb1,4GlcNAc during the investigated
stages, as well as GlcNAc in anoestrus and pregnancy.
The supra-nuclear zone of non-ciliated cells exhibited
oligosaccharides with terminal Galb1,4GlcNAc and internal
Man during oestrus and pregnancy as well as terminal aGal
and Fuc in oestrus and Neu5Ac-Galb1,3GalNAc in pregnancy.
The luminal surface of non-ciliated cells showed glycans
terminating with aGalNAc and/or Neu5Ac GalNAca1,3
GalNAca1,3Galb1,4Galb1,4GlcNAc in all specimens, oligosaccharides
with terminal Galb1,4GlcNAc and internal Man during
oestrus and pregnancy, Neu5Ac a2,6Gal/GalNAc in
anoestrus and oestrus, and glycans terminating with
Galb1,3GalNAc, Neu5A aca2,3 Galb1, 4GlcNac, Neu5ac-
Galb1,3GalNAc, Neu5Ac-Galb1,4 GlcNAc in pregnancy.
These findings show the presence of sialoglycoconjugates in
the oviductal isthmus of the mare as well as the existence of
great modifications in the glycoconjugates linked to different
physiological conditions