Tritiated fucose incorporation in the vitreous body, lens and zonules of the pigmented rabbit

Abstract

Tritiated fucose was injected into the vitreous body of adult pigmented rabbits and the location of radiolabeled residues was studied with autoradiography. The retinal internal limiting membrane region, pars plana epithelium, non-pigmented ciliary epithelium and equatorial lens epithelium were heavily labeled within a few hours. Radiolabel decreased after 24 hr, except over the pars plana and lens epithelium where the grain count remained elevated until 168 hr. Zonular-fiber radiolabel reached a maximum during the first 24 hr, while small branches of the zonules, tracts in the vitreous cortex and the anterior hyaloid membrane had maximal radiolabel at 72 hr. Modifications of these regular patterns were found in eyes that had been subjected to sclerotomy and surgical injury to the anterior vitreous body. Intravitreal injection of [ 3H]glucosamine in normal eyes resulted in low levels of radiolabel over most ocular structures compared to [ 3H]fucose. It is concluded that the radiolabeled structures of the vitreous body, lens and zonular apparatus have a continuous renewal of their glycoprotein content and that these structures are not as metabolically static as previously presumed. Fucose may serve as a marker for sites of normal and altered metabolism of glycoproteins of the vitreous body, lens and zonular apparatus.