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Melanocortin 5 Receptor (MC5R) expression is regulated by α ‐MSH in rat adrenal cells
Author(s) -
Rodrigues Adriana Raquel,
Pignatelli Duarte,
Gouveia Alexandra
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.6.lb103-c
Subject(s) - melanocortin , biology , receptor , microbiology and biotechnology , signal transduction , adrenal gland , acth receptor , endocrinology , medicine , adrenocorticotropic hormone , hormone , biochemistry
In adrenal gland cells MC2R and MC5R are the main expressed melanocortin receptors. MC2R binds exclusively ACTH while MC5R is preferential activated by α‐MSH. The signal transduction pathways activated by MC5R are still totally unknown as well as the mechanisms of its transcriptional and translational regulation. In order to characterize the MC5R expression we have developed primary cultures of rat adrenal gland cells. The morphological analysis showed that cultures were composed predominantly by adrenal cortex cells containing many cytoplasmic lipid inclusions and expressing high levels of 3β‐HSD. By immunocytochemistry assay we have found a low number of cells expressing MC5R in a non‐stimulating situation. After agonist activation, the number of MC5R immuno‐reactive cells increased significantly during the first 4h of α‐MSH incubation. Furthermore, continuous treatment with α‐MSH for 24h results in a strong decrease in MC5R expression. These observations prompted us to conclude that α‐MSH up or down‐regulates the expression of MC5R in a time dependent pattern. This could suggest a direct or indirect auto‐regulation of the MC5R translation or, most likely, of the receptor transcription mechanism. This work was supported by “Fundação Calouste Gulbenkian”. AG was also supported by “Fundação para a Ciência e Tecnologia” (SFRH/BPD/17778/2004).