The passage of extracellular tracers through the follicular epithelium of lizard ovaries

Abstract

AbstractLanthanum, a tracer of extracellular space in fixed tissue, readily traverses the follicular epithelium of the lizard Anolis carolinensis. Saccharated iron oxide injected into living lizards and peroxidase administered in vitro pass through the extracellular spaces of the follicular epithelium and accumulate in the zona pellucida. Micropinocytotic uptake of iron and peroxidase by the oocyte occurs in larger follicles which show signs of yolk accumulation. These findings confirm the morphological absence of sealing junctions in the follicular epithelium and demonstrate an extracellular route whereby materials carried in the circulation may reach the oocyte without passing through the cytoplasm of follicular cells.