Oxidised- and total non-protein bound glutathione and related thiols in gallbladder bile of patients with various gastrointestinal disorders

BACKGROUND: Glutathione is a tripeptide composed of glutamate, cysteine and glycine, accomplishing a broad range of vital functions. Synthesis of glutathione and cysteine is performed mainly in the liver, whereas most other tissues are supplied with these thiols via sinusoidal efflux into the blood. Since canalicular efflux also occurs, thiols may be present in human bile. However, thiol composition of human gallbladder bile is largely unknown, which makes it difficult to speculate on the exact function of thiols in bile. In this study we report on the levels of non-protein bound thiols in gallbladder bile of patients with various gastrointestinal disorders. METHODS: Gallbladder bile was obtained after cholecystectomy from 30 patients who were operated for pancreatic cancer, duodenal cancer, chronic pancreatitis or cholecystolithiasis. Bile was analysed for non-protein bound total- and oxidised glutathione and related thiols, by high performance liquid chromatography. RESULTS: A more than 100-fold inter-individual variation in non-protein bound thiol levels was found in human gallbladder bile of patients with a variety of gastrointestinal disorders. Bile did contain high amounts of cysteine, whereas much lower levels of glutathione, cysteinylglycine and homocysteine were detected. Most thiols were present in their oxidised forms. CONCLUSION: Thiols are present in considerable amounts in human gallbladder bile of patients with various gastrointestinal disorders, levels of cysteine being much higher than those of glutathione and other thiols. Most thiols were in their oxidised forms, which may indicate the presence of considerable chemical- or oxidative stress in the patients studied here.