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Updated: Sep 23, 2026

Pharmacologic Induction of Epidermal Melanin and Protection Against Sunburn in a Humanized Mouse Model
Published on: September 7, 2013
P-locus is a target for the melanogenic effects of MC-1R signaling: a possible control point for facultative
Janis Ancans1, Niamh Flanagan, Martin J Hoogduijn
1Department of Biomedical Sciences, University of Bradford, Bradford, United Kingdom. j.ancans@lycos.co.uk
Abstract:
Melanocortin receptor type 1 (MC-1R) is an important control point for ultraviolet ray (UVR)-induced tanning response in the skin. In this study, we show that p-locus is a downstream target for MC-1R signaling. The expression of p-locus was up-regulated by alpha-MSH as well as db-cAMP, a synthetic analogue of cAMP that mimics activation of MC-1R. Furthermore, p-locus transcript abundance was significantly increased in epidermal melanocytes of white skin with facultative (UVR-induced) pigmentation. Because p-locus product is essential for pigmentation and also has been shown to be highly polymorphic in human population, we propose that the pigmentary response to the melanocortin peptides/UVR would be affected not only by MC-1R mutations but also by the functionality of p-locus product. These factors together could account for the many different levels of tanning ability seen in the white population.
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