N Dissanayake, RS Mason
An increase in the outer `cornified' barrier layer of skin and an increase in pigment production and dispersion are two of the major adaptive responses seen in skin after UV irradiation damage. These changes seem to be protective against further damage. It has been possible to demonstrate and study these adaptive changes in skin cells in culture after UV irradiation. Several lines of evidence, including mRNA expression studies, radioimmunoassay and western blot experiments, immunofluorescence studies and biochemical experiments with neutralizing and control antibodies, all support the proposal that three proteins, produced locally by skin cells, especially after UV exposure, are involved in mediating the cornification and pigmentary responses in skin cells after UV. These compounds are transforming growth factor-b1, parathyroid hormone-related peptide and adrenocorticotrophic hormone. Although the proposal still needs to be verified in intact subjects, the possibility exists that these proteins or related chemicals could be used to bring about sun-adapted skin without the intial damaging effects of UV light.