Autoradiographic, electrophoretic, and immunocytochemical studies of glycoproteins of the rabbit iris.

L-[3H]fucose was injected either intravitreally or intra-aqueously into adult rabbits which were killed at several time points after injection. SDS-polyacrylamide gel electrophoresis and fluorography of iris extracts revealed that most of the proteins are glycoproteins containing fucose residues. Autoradiography of semi-thin histologic sections demonstrated that glycoprotein synthesis was most prominent in the epithelium of the iris, while little protein synthesis was evident in the stroma of the iris. The results of these experiments indicated that the glycoproteins of the iris undergo renewal. The protein band pattern of the iris extracts was very similar to that of extracts of the ciliary body. The high-molecular-weight cartilage matrix glycoprotein (CMGP), an intrinsic component of the ciliary body, vitreous, and aqueous humor, was detected by immunohistologic studies only in the stroma of the iris. The results of immunohistochemical analyses of the eyes of young rabbits (1-21 days old), in addition to the autoradiographic findings, strongly suggest that CMGP is not an intrinsic glycoprotein of the iris stroma, at least in this species.