[Participation of alveolar macrophages in the catabolism of fibrinogen and fibrin].

The penetration of FITC-fibrinogen in rabbit alveolar macrophages depends on Ca2+ and Mg2+. Therefore there is reason to believe the process is not restricted only by diffusion on concentration gradient, but pinocytosis takes place, which depends Ca2+. The absorption of FITC-label from fibrin by alveolar macrophages is more slow than from fibrinogen. Soluble high-molecular products of fibrin degradation can be trapped by pinocytosis. On the basis of such studies it was assumed that degradation of fibrin proceeds parietally.