Lectin histochemical study of vasculogenesis during rat pituitary morphogenesis

ABSTRACT

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. Formalin fixed paraffin sections of 10 to 20 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 alpha-L-Fucose, D-Gal, alpha, beta-D-GalNAc and D-GalNAc terminal sugars of glycoconjugates respectively. Our finding indicated that adenohypophysal cells reacted with OFA on gestational day 10 E[10] and increased progressively to E[14]. Staining intensity did not change from days 14 to17, then after increased following days to E[20] significantly [P< 0.05]. A few cells around Rathke's pouch reacted with VVA on E[13], increased to E[14] and decreased significantly afterward [P< 0.05]. Reaction of some cells around Rathke's pouch reacted with SBA on E[14]. This visible reaction was the same as E[18] and decreased later [P< 0.05]. Many cells around Rathke's pouch reacted with WFA on E[13] and increased on E[14] and E[15] and decreased thereafter [P<0.05]. 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 alpha-L-Fucose, D-Gal, alpha, beta-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