UV-Absorbing compounds in the aqueous humor from aquatic mammals and various non-mammalian vertebrates.
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.
Ringvold
Amund
A
Eye Department, Rikshospitalet University Hospital, Oslo, Norway. a.d.rinvold@klinmed.uio.no
Anderssen
Erlend
E
Jellum
Egil
E
Bjerkås
Ellen
E
Sonerud
Geir A
GA
Haaland
Peder J
PJ
Devor
Tone Pahle
TP
Kjønniksen
Inge
I
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
D005136:Eye Proteins; D014527:Uric Acid; D014443:Tyrosine; D014364:Tryptophan; D001205:Ascorbic Acid