title: UV-Absorbing compounds in the aqueous humor from aquatic mammals and various non-mammalian vertebrates.
abstract: OBJECTIVE
  To evaluate the absorbance of ultraviolet radiation (UVR) in the aqueous humor of various animal species in relation to the ambient radiation of their respective habitats, and to identify substances responsible for this absorbance. Representatives of all five classes (fish, amphibian, reptile, bird, and mammal) have been tested.
  
  
  METHODS
  Absorbance was recorded using a spectrophotometer. The ascorbic and uric acid concentrations were determined by HPLC, and the amino acid profiles with an automatic analyzer. Screening for potential UV-absorbing substances was performed by HPLC and a total of 12 species were examined, 7 of them birds.
  
  
  RESULTS
  UV-absorbing substances in the aqueous humor were proteins, tryptophan, tyrosine and ascorbic and uric acid. In addition, an unknown UV-absorbing component present in bird aqueous humor caused a high, red-shifted UV-absorbance spectrum, particularly in tentatively heavily exposed species such as goose when migrating at 10,000 m altitude. By comparison, the UV absorbance above the 288-nm wavelength was low in the aqueous humor of fish, frogs, aquatic mammals and two ground-living birds. The crocodile, whose aqueous humor contained significant amounts of both ascorbic and uric acid, revealed a concentration mechanism for ascorbic acid.
  
  
  CONCLUSIONS
  The UV absorbance of aqueous humor varies considerably from one species to the next, and independent of class. It is noteworthy that the species being at highest risk for high-dose UV exposure, the migrating goose, showed the most red-shifted spectrum.
authors.affiliation: Eye Department, Rikshospitalet University Hospital, Oslo, Norway. a.d.rinvold@klinmed.uio.no
authors.forename: Amund
authors.initials: A
authors.lastname: Ringvold
authors.forename: Erlend
authors.initials: E
authors.lastname: Anderssen
authors.forename: Egil
authors.initials: E
authors.lastname: Jellum
authors.forename: Ellen
authors.initials: E
authors.lastname: Bjerkås
authors.forename: Geir A
authors.initials: GA
authors.lastname: Sonerud
authors.forename: Peder J
authors.initials: PJ
authors.lastname: Haaland
authors.forename: Tone Pahle
authors.initials: TP
authors.lastname: Devor
authors.forename: Inge
authors.initials: I
authors.lastname: Kjønniksen
mesh_terms: D000042:Absorption; D000663:Amphibians; D000818:Animals; D001082:Aqueous Humor / Q000378:metabolism / Q000528:radiation effects*; D001205:Ascorbic Acid / Q000528:radiation effects; D001717:Birds; D002851:Chromatography, High Pressure Liquid; D005136:Eye Proteins / Q000528:radiation effects; D005399:Fishes; D008322:Mammals; D012104:Reptiles; D013045:Species Specificity; D013056:Spectrophotometry, Ultraviolet; D014364:Tryptophan / Q000528:radiation effects; D014443:Tyrosine / Q000528:radiation effects; D014466:Ultraviolet Rays; D014527:Uric Acid / Q000528:radiation effects
chemical_list: D005136:Eye Proteins; D014527:Uric Acid; D014443:Tyrosine; D014364:Tryptophan; D001205:Ascorbic Acid