Uveal melanocytes do not respond to or express receptors for alpha-melanocyte-stimulating hormone
| Autor: | Huiquan Zhao, Steven A. McCormick, Li Li, James J. Nordlund, Dan-Ning Hu, Raymond E. Boissy |
|---|---|
| Rok vydání: | 2006 |
| Předmět: |
medicine.medical_specialty
Melanocyte-stimulating hormone Tyrosine 3-Monooxygenase Tyrosinase Immunocytochemistry Melanocyte Biology Internal medicine medicine Humans Northern blot Receptor Uvea Cells Cultured Skin Melanins Membrane Glycoproteins integumentary system Eye Color Monophenol Monooxygenase Blotting Northern eye diseases Intramolecular Oxidoreductases Endocrinology medicine.anatomical_structure alpha-MSH Melanocytes sense organs Choroid Oxidoreductases Receptor Melanocortin Type 1 hormones hormone substitutes and hormone antagonists |
| Zdroj: | Investigative ophthalmologyvisual science. 47(10) |
| ISSN: | 0146-0404 |
| Popis: | PURPOSE Whereas cutaneous pigmentation increases after exposure to ultraviolet (UV) irradiation, ocular pigmentation does not. This study was designed to examine the evidence that alpha-melanocyte-stimulating hormone (alpha-MSH), which is thought to be the mediator of UV response in the skin, has any role to play in uveal melanocytes. METHODS Human uveal melanocytes derived from the choroid and the iris were cultivated by using eyes harvested from adult cadaveric donors and were assessed by Northern blot analysis for growth and melanogenic response to alpha-MSH and expression of the receptor for alpha-MSH (MC1-R). In addition, expression of alpha-MSH was evaluated in ocular tissue by immunocytochemistry. RESULTS Uveal melanocytes, unlike cutaneous melanocytes in vitro, exhibited no stimulation of proliferation in response to alpha-MSH at dosages ranging from 0.1 to 100 muM. In addition, tyrosine hydroxylase, DOPA oxidase, and protein levels for tyrosinase, TRP-1, and TRP-2 were not influenced by alpha-MSH. Associated with the lack of alpha-MSH response in cultured uveal melanocytes was the absence of expression of the receptor for alpha-MSH (MC1-R), as assessed by Northern blot analysis. Also in contrast to the skin, pigmented ocular tissue lacked expression of the alpha-MSH ligand, as assessed by immunocytochemistry. CONCLUSIONS In conclusion, ocular pigmentation does not appear to be regulated by melanocyte stimulating hormone. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|