HAIR CYCLE-DEPENDENT PRODUCTION OF ACTH IN MOUSE SKIN

We investigated the functional determinants of the cutaneous expressio n of elements of the hypothalamic-pituitary-adrenal axis. In the prese nt work, the presence of adrenocorticotropin (ACTH) peptide in skin of C57/BL6 mouse was demonstrated by reversed-phase HPLC analysis combin ed with specific radioimmunoassay. ACTH concentration that was low in telogen, increased during anagen in two steps: a rapid phase in anagen I, and a slower rise that reached its peak in anagen VI. Immunofluore scence localized the ACTH antigen to the basal layer of epidermis, out er root sheath of hair follicle and subcutaneous muscle of anagen VI s kin. At physiological plasma concentration (10(-9) M), ACTH selectivel y stimulated DNA synthesis in dermis, while pharmacological doses (10( -7)-10(-6) M) inhibited DNA synthesis in both dermis and epidermis. In conclusion, we suggest that local production of ACTH may represent a regulatory element in the control of skin functions including hair gro wth. (C) 1998 Elsevier Science B.V. All rights reserved.