Abstract
Growth factors have been found in vitreous fluid, in which they regulate retinal function and provide markers of ocular dysfunction. Since growth hormone (GH) has recently been discovered in the eyes of rodents and embryonic chicks and found to be neuroprotective for retinal ganglion cells, the possible presence of GH in the human retina and vitreous fluid has been assessed. GH-immunoreactivity in the retina and vitreous fluid of cadavers and in the vitreous fluid of patients with ocular dysfunction was determined by Western blotting. GH-immunoreactivity, identical in size (22kDa) to recombinant pituitary GH was found in proteins extracted from the retina and in the vitreous fluid of patients with ocular disease (proliferative diabetic retinopathy, epiretinal membrane and vascular hemorrhage) and individuals with no history of ocular disease. GH-immunoreactivity was also detected in large, discrete cells in the retinal ganglion cell layer, in which GH staining was mainly within the nuclear compartment. The novel presence of GH in the human retina and vitreous fluid suggests GH may have roles in visual function and be involved in the pathogenesis of ocular disease.