Lectin Histochemical Study of Vasculogenesis During Rat Pituitary Morphogenesis

Objective(s) The aim of this study was to investigate glycoconjugates distribution patterns as well as their changes during the course of pituitary portal vasculogenesis and angiogenesis. Materials and Methods Formalin fixed paraffin sections of ۱۰ to ۲۰ days of Sprague Dawly rat fetuses were processed for histochemical studies using four different horseradish peroxidase (HRP) conjugated lectins. Orange peel fungus (OFA), Vicica villosa (VVA), Glycine max (SBA) and Wistaria floribunda (WFA) specific for α-L Fucose, D-Gal, α, ß-D-GalNAc and D- GalNAc terminal sugars of glycoconjugates respectively. Results Our finding indicated that adenohypophysal cells reacted with OFA on gestational day ۱۰ (E۱۰) and increased progressively to E۱۴. Staining intensity did not change from days ۱۴ to۱۷, then after increased following days to E۲۰ significantly (P< ۰.۰۵). A few cells around Rathke’s pouch reacted with VVA on E۱۳, increased to E۱۴ and decreased significantly afterward (P< ۰.۰۵). Reaction of some cells around Rathke’s pouch reacted with SBA on E۱۴. This visible reaction was the same as E۱۸ and decreased later (P< ۰.۰۵). Many cells around Rathke’s pouch reacted with WFA on E۱۳ and increased on E ۱۴ and E۱۵ and decreased thereafter (P< ۰.۰۵). Conclusion Reactions of OFA and other tested lectins with endothelial cells around Rathke’s pouch and developing pars distalis were different. These results suggest that embryonic origin of hypophiseal pituitary portal (HPP) system endothelial cells are not the same and our finding also indicated that glycoconjugates with terminal sugars α-L-Fucose, D-Gal, α, ß-D-GalNAc may play critical role(s) in cell interactions and tissue differentiations such as vasculogensis and angiogenesis as well as other developmental precursors in formation of the pituitary gland.

Keywords:

Angiogenesis , Glycoconjugates , Lectin , Pituitary , Rat