title: Urinary excretion of 5-S-cysteinyldopa in relation to skin type, UVB-induced erythema, and melanocyte proliferation in human skin.
abstract: 5-S-Cysteinyldopa (5-S-CD) is found in all pigment-producing cells and is the major precursor of phaeomelanin. However, the melanocyte specificity of the compound has been questioned. In order to elucidate the origin of 5-S-CD, we have now systematically studied the relationship between the 5-S-CD excretion in urine and the size of the melanocyte organ, UV-induced melanocyte proliferation, skin type, and the erythemal reaction. The skin type had no influence on the basal excretion of 5-S-CD. There was no significant correlation between the basal 5-S-CD excretion and the size of the melanocyte organ; that is, the number of skin melanocytes and nevi. During the irradiation, subjects with skin type II developed a more pronounced erythema (p less than 0.01) and had a significantly higher 5-S-CD excretion than those with skin type III-IV (p less than 0.01). No correlation was found between 5-S-CD excretion and UV-induced melanocyte proliferation. The lack of correlation between the basal 5-S-CD excretion and skin type or number of melanocytes suggests that the basal 5-S-CD in urine is mainly of extra-melanocytic origin. Our findings favor the view that the increase in 5-S-CD excretion during UV irradiation is due to UV damage.
mesh_terms: D000328:Adult; D014408:Biomarkers, Tumor / Q000652:urine; D002455:Cell Division / Q000528:radiation effects*; D003548:Cysteinyldopa / Q000652:urine*; D004295:Dihydroxyphenylalanine / Q000031:analogs & derivatives*; D000078404:Epidermal Cells; D004817:Epidermis / Q000528:radiation effects; D004890:Erythema / Q000209:etiology / Q000473:pathology / Q000652:urine*; D005260:Female; D006801:Humans; D008297:Male; D008544:Melanocytes / Q000166:cytology* / Q000528:radiation effects; D008875:Middle Aged; D012867:Skin / Q000166:cytology* / Q000528:radiation effects; D014466:Ultraviolet Rays / Q000009:adverse effects
chemical_list: D014408:Biomarkers, Tumor; D003548:Cysteinyldopa; D004295:Dihydroxyphenylalanine