Fig. 5. Specificity of endocytosis of ¹²⁵I-labelled lipopolysaccharide in cultured cod atrial endocardial endothelial cells (aEECs). Monolayer cultures of aEECs in 2 cm² wells were incubated for 2 h at 12°C with trace amounts of labelled ligand (approximately 2x10⁴ cts min^–1; 3 ng) alone (Control) or together with excess amounts of unlabelled macromolecules (100 µg ml^–1). The results are presented as a percentage of the control value and are means + S.E.M. of three independent experiments. F-LPS, fluorescein-labelled lipopolysaccharide; FSA, formaldehyde-treated serum albumin.