The distribution of endothelin-A- and B- (ETA, ETB)receptor subtypes was compared in colorectal cancer to that in normal colon and their expression in the colorectal cancer cell lines LIM1215, HT29, SKCO1, SKCO17 and LoVo was determined, using gross and high resolution autoradiography and quantified by densitometry. ETA and ETB binding sites were expressed by all the cell lines. There was significantly (p = 0.008) higher expression of ETA-receptors by cancers (205.95 dpm × 1000/mm2) compared to normal colon (129.19 dpm × 1000/mm2). However, for ETB-receptors, this was reversed, with significantly (p = 0.008) higher expression of ETB binding in normal colon (207.00 dpm × 1000/mm2) than in tumours (122.35 dpm × 1000/mm2).
Departments of Surgery and Molecular Pathology & Clinical Biochemistry, Royal Free and University College Medical School, London, U.K.
Address correspondence and reprint requests to Michael R. Dashwood, Department of Molecular Pathology & Clinical Biochemistry, Royal Free and University College Medical School, Royal Free Campus, Pond Street, NW3 2QG, London, U.K.
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