Receptor-mediated endocytosis of lactate dehydrogenase M4 by liver macrophages: a mechanism for elimination of enzymes from plasma. Evidence for competition by creatine kinase MM, adenylate kinase, malate, and alcohol dehydrogenase.

We have previously shown that the rapid clearance of intravenously injected lactate dehydrogenase M4 from plasma is mainly due to endocytosis by macrophages in liver, spleen, and bone marrow. We have now studied endocytosis of lactate dehydrogenase M4 in detail, using freshly isolated rat liver macrophages (Kupffer cells) in vitro. 125I-lactate dehydrogenase M4 rapidly accumulated in the cells and was subsequently degraded to trichloroacetic...