Expression of hypothalamic neurohormones and their receptors in the human eye

Abstract

Extrapituitary roles for hypothalamic neurohormones have recently become apparent and clinically relevant, based on the use of synthetic peptide analogs for the treatment of multiple conditions including cancers, pulmonary edema and myocardial infarction. In the eye, it has been suggested that some of these hormones and their receptors may be present in the ciliary body, iris, trabecular meshwork and retina, but their physiological role has yet to be elucidated. Our study intends to comprehensively demonstrate the expression of some hypothalamic neuroendocrine hormones and their receptors within different retinal and extraretinal structures of the human eye. Immunofluorescence, Western blot analysis, and RT-PCR were used to evaluate the qualitative and quantitative expression of Luteinizing Hormone Releasing Hormone (LHRH), Growth Hormone Releasing Hormone (GHRH), Thyrotropin Releasing Hormone (TRH), Gastrin Releasing Peptide (GRP) and Somatostatin as well as their respective receptors (LHRH-R, GHRH-R, TRH-R, GRP-R, SST-R1) in cadaveric human eye tissue and in paraffinized human eye tissue sections. The hypothalamic hormones LHRH, GHRH, TRH, GRP and Somatostatin and their respective receptors (LHRH-R, GHRH-R, TRH-R, GRPR/BB2 and SST-R1), were expressed in the conjunctiva, cornea, trabecular meshwork, ciliary body, lens, retina, and optic nerve.