RETINOBLASTOMA AQUEOUS-HUMOR - AROMATIC-AMINO-ACIDS

Aqueous humor from children with retinoblastoma obtained at enucleatio n and from eyes with adult cataracts were assayed with electrochemical liquid chromatography (Model 5500 Coulochem electrode array system) f or metabolites of tyrosine, tryptophan metabolic pathways, catecholami ne degradation pathways and ascorbate. More than 20 metabolites were i dentified in human aqueous for the first time. High levels of ascorbat e were found in aqueous of eyes with adult cataracts (254, 336 ng/ml). Tyrosine metabolism in both sets of eyes was through dopamine. Vandyl mandelic acid (VMA), homovanillic acid (HVA), and 3-methoxy, 4-hydroxy phenylglycol (MHPG) were all detected in retinoblastoma eyes. Although eyes with either adult cataracts or childhood retinoblastoma convert tryptophan through the serotonin pathway, retinoblastoma eyes metaboli ze tryptophan-through the kynurenine pathway to a greater degree than adult cataract eyes.