Morphogenesis and nature of the pigment granules in the adult human retinal pigment epithelium

Summary The pigment epithelial cells of the retina are a layer of highly specialized melanocytes. Beginning in the early embryonic period they produce melanin throughout the entire life. The Golgi apparatus plays a key role in the biosynthesis of melanin. The following steps can be distinguished morphologically: (a) Golgi-vesicles, (b) intermediate vesicles, (c) melanosomes, (d) melanin granules. Structures with a ringlike appearance that are described as lipofuscin granules in the literature prove to be altered intermediate vesicles and melanosomes.This investigation was carried out in part at the Francis I. Proctor Foundation for Research in Ophthalmology, San Francisco, California, U.S.A., and supported by United States Public Health Service Program Project Grant EY 00310, and Deutsche Forschungsgemeinschaft, Training Grant Nr. Sp 102/1.