The melanocortin 5 receptor is expressed in human sebaceous glands and ratpreputial cells

Melanocortins regulate pigmentation, adrenal hormone secretion, immune func tions, lipid metabolism, and feeding behaviors in rodents. These peptides i nclude adrenocorticotrophic hormone, melanocyte stimulating hormone, beta-l ipotrophin, and the endorphins. Lipid metabolism in sebaceous glands and pr eputial glands of rodents is regulated by alpha-melanocyte stimulating horm one, the major agonist for melanocortin receptors. Five melanocortin recept or subtypes have been identified that differ in their tissue localization a nd affinities for melanocortin ligands. Targeted disruption of the melanoco rtin 5 receptor in transgenic mice results in widespread dysfunction of exo crine glands, including a marked decrease in sebum production. A role for m elanocortins in the modulation of human sebum production has not been estab lished. The goal of this study is to determine which melanocortin receptors are expressed in human sebaceous glands. Messenger RNA was isolated from h uman sebaceous glands and the reverse transcriptase polymerase chain reacti on was performed using primers specific for each of the melanocortin recept or subtypes. Transcripts were detected for the melanocortin 5 receptor. A p olyclonal chicken antihuman antibody to the melanocortin 5 receptor localiz ed to sebaceous glands, eccrine glands, hair follicles, and epidermis in hu man skin, rat skin, cultured human sebocytes, and rat preputial cells. Pres ence of the melanocortin 5 receptor protein in human sebaceous glands and r at preputial glands was further verified by Western blotting. These data su pport further investigation of the role of melanocortins in the regulation of human sebum production and support the use of the rat preputial system a s an experimental model in sebaceous gland physiology.