[Endocrinological reactions following UV A whole body irradiation]

The basal secretion of proteo-hormones alpha-MSH and ACTH in plasma as well as the changes of the plasma concentrations following UV A-whole-body irradiation were investigated on 40 young male volunteers with different pigmentation levels (Caucasians: skin types I, II, III. Blacks: skin type VI). Significantly lower mean basic values of alpha-MSH and ACTH of light-haired persons in comparison with dark-haired and black persons (p less than 0,05) were demonstrated. We observed furthermore a significant increase of these proteo-hormones (alpha-MSH: skin type I: 26,7%, skin type II: 22,7%) in persons less pigmented within a short time after UV A whole-body irradiation in contrast to the more pigmented volunteers. These results prove a cutaneous peripheral sensor for UV A-rays, reacting with a different sensitivity depending on disposition and inducing endocrinological reactions. How this cutaneous-hypothalamic-pituitary stimulus mediation functions in detail is not completely revealed up to now. In what respect the present results, which can be explained as a consequence of evolutionary development, have a connection with the induction of melanoma remains to be seen.