Prolonged Increase of cis-Urocanic Acid Levels in Human Skin and Urine after Single Total-body Ultraviolet Exposures

• Published in: Photochemistry and photobiology Vol. 65; no. 3; pp. 593 - 598
• Main Authors: Kammeyer, Arthur, Pavel, Stanislav, Asghar, Syed S., Bos, Jan D., Teunissen, Marcel B. M.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01-03-1997
• Subjects: Adolescent; Adult; Chromatography, High Pressure Liquid; Female; Humans; Male; Middle Aged; Skin - metabolism; Skin - radiation effects; Ultraviolet Rays; Urocanic Acid - blood; Urocanic Acid - metabolism; Urocanic Acid - urine
• ISSN: 0031-8655; 1751-1097
• DOI: 10.1111/j.1751-1097.1997.tb08611.x

Cis-urocanic acid (cis-UCA), a mediator of immunosuppression, is formed from trans-UCA upon UV-exposure of the skin. This study describes a liquid chromatographic method for the simultaneous quantification of cis- and trans-UCA in skin, urine and plasma of nonirradiated volunteers. It also describes cis- and trans-UCA kinetics in UV-irradiated volunteers. New procedures to remove interfering substances from urine and plasma are reported. Normal levels of cis-UCA in skin, urine and plasma of nonirradiated volunteers were 0.5 nmol/cm2, 0.03 mumol/mmol creatinine (median 0.00) and undetectable and those of trans-UCA were 17.1 nmol/cm2, 1.36 mumol/ mmol creatinine and 0.5 microM, respectively. Upon single total body UVB (290-320 nm) exposures of 250 J/m2, epidermal cis-UCA levels immediately reached a maximum and returned to basic levels 3 weeks later. The cis-UCA levels in urine reached a maximum in 5-12 h postirradiation and reached baseline values in 8-12 days. Additionally, a single total body UVA (320-400 nm) irradiation of 200 kJ/m2 yielded a similar pattern. The kinetics of cis-UCA in plasma could not be followed due to low concentrations; however, that of skin and urine was informative in relation to solar exposures and phototherapy.