Localization of ³H-glucosamine and ³⁵S-sulfate in the hamster retina: Light and electron microscopic autoradiography

The localization of ³H-glucosamine and ³⁵S-sulfate in the hamster retina was studied by light and electron microscopic autoradiography. Exposed silver grains were concentrated in the nerve fiber, inner plexiform, outer plexiform and inner segment layers. The heaviest labeling was observed over the inner segment layer in the glucosamine experiment and over the nerve fiber layers in the sulfate experiment. Specimens from 12- and 16-day-old hamsters showed slightly heavier labeling than did those from adult animals. In the electron microscopic autoradiography using ³H-glucosamine, grains were initially associated with the retinal pigment epithelium, the inner segment and the Muller cell and were subsequently displaced into the spaces between the retinal pigment epithelium and the outer segment and into the nerve fiber layers. The labelled sulfates in the electron microscopic autoradiography were seen in the nerve fiber, plexiform and photoreceptor layers. These data indicate that glycosaminoglycans may be synthesized in the retinal pigment epithelium, the inner segment and the Muller cell.