Fate of Hemoglobin Pincytosed by Macrophages in Vitro

Cultivated mouse peritoneal macrophages provide a convenient in vitro system for the study of pinocytosis. Homogeneous cell populations are easily collected and can be cultivated in a manner suitable for obtaining morphological or biochemical data. Recent studies of peritoneal macrophages in vitro have clarified many aspects of the physiology of pinocytosis, particularly its relationship to the formation of lysosomes (3 8). When cultivated in the presence of serum, macrophages pinocytose continually. Pinocytic vesicles migrate to the perinuclear region of the cell, where they acquire acid hydrolases to become secondary lysosomes. Both endogenous hydrolases and exogenous macromolecules can be demonstrated in macrophage lysosomes, which are undoubtedly the major site of intracellular digestion. This study and an earlier one were undertaken for a COHN. From The Rockefeller University,