Total body exposure to ultraviolet radiation does not influence plasma levels of immunoreactive beta-endorphin in man

Background/Aims: A growing number of reports support evidence of proopiomel anocortin (POMC)-derived peptides in human skin cells, although not consist ently. Also the effect of ultraviolet radiation (UVR) on cutaneous and plas ma levels of these POMC peptides has not been established unequivocally. We hypothesized that production of beta -endorphin (betaE) may explain the se nse of well-being many people experience when sun-bathing. The aim of the p resent study was to investigate whether exposure of the skin to UVR elevate s plasma betaE. Method. Healthy volunteers (n = 26) received a single, weighted dose of 15 J/cm(2) of UVA. Several times during the hour following irradiation, plasma betaE-immunoreactivity (betaE-IR) was determined by radioimmunoassay. The effect of repeated exposure was assessed in 35 patients treated with UVB, U VA, or UVA-1. Plasma ACTH-IR was monitored in parallel. Results: Overall, plasma levels of betaE-IR and ACTH-IR showed no significa nt changes during the experiment, indicating that these peptides are not in fluenced by single or repeated exposures to UVR of different wavelengths. Conclusion: On the basis of these results, the skin does not appear to cont ribute significantly to the levels of circulating betaE or ACTH. These data offer no support for the hypothesis that exposure to UVR leads to an incre ased concentration of circulating betaE, which could contribute to the feel ing of well-being that often accompanies sun-bathing.