Microenvironment of Breast Tissue: Lithocholic Acid and Other Intestinal Steroids

摘要

Although it is known that bile acids including lithocholic acid are present inbreast cyst fluid, analysis by gas-liquid chromatography-mass spectrometry requires the preparation of volatile derivatives. To identify the natural state of the bile acids in breast cyst fluid, HPLC was utilized because of the potential for identifying both conjugated and esterified bile acids. For detection, preparation of the 5,6-dimethoxycoumarin carboxyl ester derivatives was found more useful than either the 1-bromoacetylpyrene or pyrene 1-carbonyl azide derivatives. Using a binary gradient elution system conditions were found for the separation and identification of glycine conjugated, nonconjugated and esterified bile acids. A peak-shift technique using cholylglycine hydrolase and/or solvolysis was found useful for identifying esterified and taurine conjugated bile acids. Application of the technique to the identification of conjugated and esterified bile acids in breast cyst fluid was found limited by the finding of other overlapping organic acids. For definitive identification coupling of HPLC with fluorescence detection to a mass spectrum detector can distinguish the bile acids from these other components.