The location of insulin receptors in bovine retina and isolated retinal cells.

Abstract

The binding of insulin to its cell-surface receptor is the sole means by which the hormone influences cellular activity. The location of insulin receptors in bovine retina and on isolated retinal cells was investigated to determine the specific cells sensitive to insulin. Insulin receptors were located in frozen retinal sections prepared from enucleated bovine eyes, with polyclonal anti-insulin receptor antibodies using an immuno-peroxidase method. Isolated cells were obtained by enzymatic and physical dispersion of bovine retinal tissue. Insulin receptors on isolated cells were located by a monoclonal anti-insulin receptor antibody using an immunogold silver staining technique. Insulin receptors demonstrated a widespread distribution throughout the bovine retina, being present in all retinal layers. A particular association with the plexiform layers and Müller cells was identified in the frozen sections. Consistent with these findings, insulin receptors were predominantly located on dendritic processes of isolated retinal neurones and on Müller cells. The widespread distribution of retinal insulin receptors in the bovine retina supports the hypothesis that insulin has a role in regulating retinal activity. Insulin receptors associated with plexiform regions suggests that insulin may influence neural activity, while receptors on Müller cells indicate that insulin may have a role in metabolic or functional mechanisms in bovine retina.