The concentration of kynurenine has been measured in the serum of patients with rheumatoid arthritis and in a control group. The mean serum concentration was 2.27 +/- 0.688 mug/ml for patients with rheumatoid arthritis and 2.95 +/- 0.825 mug/ml for the control group.KYNURENINE: creatinine clearance ratios were higher in the rheumatoid arthritis than in the control group. These data suggest that...

BACKGROUND Patients with schizophrenia show increased brain and cerebrospinal fluid (CSF) concentrations of the endogenous N-methyl-D-aspartate receptor antagonist kynurenic acid (KYNA). This compound is an end-metabolite of the kynurenine pathway, and its formation indirectly depends on the activity of kynurenine 3-monooxygenase (KMO), the enzyme converting kynurenine to 3-hydroxykynurenine. ...

The pellagragenic effect of leucine (Leu) has been proposed to involve modulation of L-tryptophan (Trp) metabolism along the hepatic kynurenine pathway. Here, we discuss some of the mechanisms suggested and report the effects in healthy volunteers of single doses of Leu (4.05-6.75 g) administered in a 16-amino acid mixture on concentrations of plasma Trp and its kynurenine metabolites. Flux of ...

The in vivo molt-inhibitory effects of the ecdysone biosynthesis inhibitors 3-hydroxy-L-kynurenine and xanthurenic acid were investigated. These ecdysone biosynthesis inhibitors, isolated from the eyestalks of blue crabs (Callinectes sapidus), were injected into eyestalk-ablated crayfish (Procambarus clarkii). The active factor was found to be species-nonspecific within crabs and crayfish. The ...

Comparisons with the distribution of intramitochondrial marker enzymes have indicated that kynurenine aminotransferase is present in the inner membrane fraction of rat liver mitochondria. It appears to be weakly bound to the inner membrane because it is easily solubilized by increasing the concentration of digitonin. With the use of a-ketoglutarate or oxalacetate as amino group acceptor, the am...

(1) In fetal rat liver and kidney, kynurenine 3-hydroxylase activity was absent. It began to appear after birth and reached the adult level when the body weight of rat became about 50 g (approximately 25 days after birth). (2) In kidney, the change of kynurenine 3-hydroxylase activity after the daily subcutaneous injection of progesterone or estradiol-17 f3 in a dose of 2.7 mg or 30 pg per 100 ...

Batesian mimicry protects animals from predators through resemblance with distasteful models in shape, color pattern, or behavior. To elucidate the wing coloration mechanisms involved in the mimicry, we investigated chemical composition and gene expression of the pale yellow and red pigments of a swallowtail butterfly, Papilio polytes, whose females mimic the unpalatable butterfly Pachliopta ar...

Psychiatric patients suffering from endogenous depression and a control group without endogenous depression were given oral loads of L-tryptophan and urinary excretion determined of the tryptophan metabolites on the pyrrolase pathway: kynurenine, 3-hydroxykynurenine, and 3-hydroxyanthranilic acid. Female endogenously depressed subjects excreted significantly more kynurenine and 3-hydroxykynuren...

Parkinson's disease (PD) and Huntington's disease (HD) are progressive chronic neurodegenerative disorders that are accompanied by a considerable impairment of the motor functions. PD may develop for familial or sporadic reasons, whereas HD is based on a definite genetic mutation. Nevertheless, the pathological processes involve oxidative stress and glutamate excitotoxicity in both cases. A num...

Inflammation and depression are closely inter-related; inflammation induces symptoms of depression and, conversely, depressed mood and stress favor an inflammatory phenotype. The mechanisms that mediate the ability of inflammation to induce symptoms of depression are intensively studied at the preclinical level. This review discusses how it has been possible to build animal models of inflammati...