Autophagocytosis of melanosomes in cultured embryonic retinal pigment cells.

Autophagocytosis not only accounts for the early pigment loss found in proliferating cultured retinal pigment cells, but also occurs in slowly growing and in non-proliferating cells. Both melanosome synthesis and destruction may take place concurrently in cells. Autophagosomes may contain both fully formed melanosomes and also premelanosomes in various stages of formation, are positive for lysosomal enzyme activity, and likely represent secondary lysosomes.