Reactivity of visceral yolk sac endoderm with lectins: changes related to age and species.

The expression of receptors for lectins reacting with extraembryonal endoderm was compared between mouse and rat at different stages of gestation. Fluorescein-conjugated Helix pomatia agglutinin (HPA), Dolichos biflorus agglutinin (DBA), Sophora japonica agglutinin (SJA), peanut agglutinin (PNA), Bandeiraea simplicifolia agglutinin 1 (BSA-1) and gold-conjugated DBA and PNA were used. It was shown that the rat visceral endoderm does not express the receptors for HPA, while the mouse tissue does. Other lectins react with the visceral endoderm of both species but the reactivity disappears at different days of gestation. The control of expression of receptors for the lectins suggests that they may be involved in the recognition system important during differentiation.