γ-MSH increases intracellular cAMP accumulation and GnRH release in vitro and LH release in vivo

• Published in: FEBS letters Vol. 543; no. 1; pp. 66 - 70
• Main Authors: Stanley, S.A., Davies, S., Small, C.J., Gardiner, J.V., Ghatei, M.A., Smith, D.M., Bloom, S.R.
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 22.05.2003
• Subjects: Alpha melanocyte-stimulating hormone; alpha-MSH - administration & dosage; alpha-MSH - pharmacology; Animals; Cyclic AMP - biosynthesis; Dose-Response Relationship, Drug; Follicle Stimulating Hormone - blood; Gamma melanocyte-stimulating hormone; gamma-MSH - administration & dosage; gamma-MSH - pharmacology; Gonadotropin-releasing hormone; Gonadotropin-Releasing Hormone - metabolism; Hypothalamus; Hypothalamus - drug effects; Hypothalamus - metabolism; Injections; Luteinizing Hormone - blood; Male; Melanocortin; Preoptic Area; Rats; Rats, Wistar; Receptor, Melanocortin, Type 3; Receptors, Corticotropin - metabolism; Tumor Cells, Cultured; Melanocortin; Gonadotropin-releasing hormone; Hypothalamus; Alpha melanocyte-stimulating hormone; Gamma melanocyte-stimulating hormone
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/S0014-5793(03)00402-2

The roles of the melanocortin 3 receptor (MC3-R) and its agonist, γ 2-melanocyte-stimulating hormone (γ 2-MSH) in the regulation of the hypothalamo-pituitary-gonadal (HPG) axis are poorly understood. Here we show γ 2-MSH stimulated intracellular cAMP accumulation and gonadotrophin-releasing hormone (GnRH) secretion in the immortalised GnRH cell line GT 1-7. The MC3/4-R antagonist Agrp blocked these actions. Reverse transcriptase polymerase chain reaction demonstrated GT 1-7 cells express MC3-R mRNA. γ 2-MSH also stimulated GnRH release from hypothalamic explants. In vivo, γ 2-MSH administration into the medial preoptic area significantly increased plasma luteinising hormone. MC3-R and γ 2-MSH may modulate the HPG axis.