[Relationship between tryptophan metabolism and the state of melaninogensis]

In studying the excretion of tryptophan and the activity of tryptophan pyrrholase of the liver in black and albino rabbits it was revealed that the kinurenine, kinurenic and xanthurenic acids, 3-hydroxykinurenin, anthranylic acid and 5-hydroxyindolylactic acid levels in the urine collected before the L-tryptophane loading differed in these animals. No 3-hydroxyanthranylic acid was found in the initial urine of these rabbits. A sharp intensification of excretion of all the tryptophane metabolites studied followed the administration of L-tryptophane to albino rabbits, and a harper elevation of kinurenic and xanthurenic acid excretion--to black rabbits. In comparison with black rabbits, the tryptophan pyrrholase of the liver of albino rabbits reached to the L-tryptophan administration more intensively.

Separation and quantitative analysis of furosemide and 4-chloro-5-sulfamoylanthranilic adid (CSA) by high pressure liquid chromatography

After extraction by ether from acidified plasma or urine and concentration into basic phosphate buffer, furosemide and 4-chloro-5-sulfamoylanthranilic acid (CSA) were separated on a high pressure liquid ion-exchange system and measured fluorometrically. Sensitivity is 0.2 mug/ml of ether compound in plasma and 0.1 mug/ml in urine with an 8% coefficient of variation. Interference by porphyrins in urine was eliminated by subtracting a second fluorometric measurement at a different wave-length from that used for furosemide. No quenching at this wave-length is seen with concentrations of furosemide up to 50 mug/ml. Standard curves of furosemide and CSA are linear from 0.2 mug/ml to 50 mug/ml.

[Studies on tryptophan metabolism in untreated phenylketonuric patients]

The products of the oxidative degradation of tryptophan via the kynurenine pathway were quantitatively determined in the urine of ten untreated patients with phenylketonuria, aged 4--35 years. All the patients were sevrely mentally retarded. The results of the analysis suggest a division of the patients into two groups, A and B. The patients of group A showed a basal urinary excretion of kynurenine, kynurenic acid, 3-hydroxykynurenine and xanthurenic acid which lies in the lower part of the normal range. The increase in excretion of tryptophan metabolites under tryptophan loading was, however, significantly less than in controls. On the average, only 0.63 % of the load was excreted in the form of these assayed metabolites; in contrast, the control value is 1,13 %. In group B, the rate of excretion was higher than normal under basal and loading conditions. The post-tryptophan excretion was four times greater than that of controls (4.64 %). 3-hydroxyanthranilic acid could only be detected in group B after loading. The metabolite 8-hydroxyquinaldic acid, which is supposed to be an abnormal metabolic product of tryptophan, was excreted in milligram amounts. The analysis of the metabolites of 3-hydroxyanthranilic acid showed that the excretion of N1-methylnicotinamide and N1-methyl-2-pyridone-5-carboxamide was within the normal range. The excretion of nicotinic acid and its amide was sporadic in both the patients and controls. Other theoretically possible metabolites in the pathway could not be found. A number of unidentified metabolites could be detected by thin-layer chromatography in the basal state. The excretion of these metabolites was greatly augmented after tryptophan loading. Other substances which were not detectable in the basal state became evident on loading. A number of these metabolites are characteristic either of group A or B. The structural identification of one of the new products has been hindered by its instability. A stable cleavage product was identified as omicron-aminoacetophenon by mass-spectroscopy. This metabolite its typical for group B. The possible influence of the blood phenylalanine on the metabolism of tryptophan in phenylketonuria is discussed.

The concentration of free and conjugated 3-hydroxyanthranilic acid in the urine of bladder tumour patients before and after therapy, measured with an enzymatic method

The basal concentration of the tryptophan metabolite 3-hydroxyanthranilic acid (3OHA), which has carcinogenic properties, was measured with an enzymatic method of determination which allowed separate measurement of free and conjugated 3OHA. The concentration of free 3OHA in untreated bladder cancer patients was significantly (P <0·001) higher than in a healthy control group, but after local therapy the concentration was significantly lower than before treatment (P <0·01). The concentration of conjugated 3OHA was nearly constant in the three groups. It was concluded that other factors than a genetic determined abnormality might be operating in bladder cancer patients which could lead to an abnormal concentration of 3OHA in their urine.