Content of kynurenic acid and activity of kynurenine aminotransferases in mammalian eyes.
The present study investigated the kynurenic acid (KYNA) contents and kynurenine aminotransferase (KAT I and II) activity in structures of the human, monkey, rabbit and bovine eye. KYNA levels were investigated with HPLC and detected fluorimetrically. The activity of KAT I and II was assayed as quantitative analysis of newly synthesized KYNA in vitro. Mean KYNA levels (+/-SD) in the human retina and vitreous body were 36.8 +/- 7.6 and 33.1 +/- 6.2 pmol/g wet tissue weight, respectively. In human eyes, KAT I activity in the vitreous body was 0.57 +/- 0.28, that of KAT II was 2.56 +/- 0.69. KAT I activity in the retina was 3.42 +/- 1.17 and that of KAT II 10.75 +/- 9.2. (KAT activity is expressed as KYNA synthesis in picomoles per gram wet tissue weight per hour.) The values of KYNA and KAT observed in other mammalian species tested were in the same range. In conclusion, KYNA and KAT enzymatic activity are present in the structures of human and other mammalian eyes.
Zarnowski
Tomasz
T
Tadeusz Krwawicz Chair of Ophthalmology and 1st Eye Hospital, Lublin, Poland. zaro@panaceum.am.lublin.pl
Rejdak
Robert
R
Zagorski
Zbigniew
Z
Juenemann
Anselm G M
AG
Zrenner
Eberhart
E
Kocki
Tomasz
T
Urbanska
Ewa M
EM
Turski
Waldemar A
WA
D000818:Animals; D001082:Aqueous Humor / Q000737:chemistry; D002417:Cattle; D005123:Eye / Q000737:chemistry*; D006801:Humans; D007498:Iris / Q000737:chemistry; D007736:Kynurenic Acid / Q000032:analysis*; D008253:Macaca mulatta; D011817:Rabbits; D012160:Retina / Q000737:chemistry; D000637:Transaminases / Q000032:analysis*; D014822:Vitreous Body / Q000737:chemistry
D000637:Transaminases; C021481:kynurenine-oxoglutarate transaminase; D007736:Kynurenic Acid