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Stimulation of the receptor for melanocyte‐stimulating hormone by retinoic acid
Author(s) -
Chakraborty Ashok K.,
Orlow Seth J.,
Pawelek John M.
Publication year - 1990
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(90)80543-r
Subject(s) - retinoic acid , stimulation , melanocyte stimulating hormone , receptor , endocrinology , medicine , cell , chemistry , hormone , melanocyte , cell culture , biology , melanoma , biochemistry , cancer research , genetics
Treatment of Cloudman S91 melanoma cells with retinoic acid (RA) inhibits MSH‐induced tyrosinase activity and melanin formation [(1990) J. Invest. Dermatol. 94, 461‐464]. We report here, however, that in spite of inhibiting MSH‐induced pigmentation, RA treatment caused a marked increase in MSH binding capacity for both cell surface and internal MSH binding sites. The stimulation was dose‐ and time‐dependent and reversible, with half‐maximal effects seen at 2 μM RA. Stimulation of MSH binding was seen as early as 3 h after exposure of cells to RA. Cell surface and internal binding activity increased in concert. Scatchard analyses indicated that increased MSH binding resulted from a 3–4‐fold increase in the number of sites with no significant difference in their affinity for MSH. It appears that in suppressing MSH‐induced melanogenesis, RA elicited a compensatory up‐regulation of the MSH receptor system.