Promotive effect of estrogen on hepatocarcinogenesis in rats : The effect of tamoxifen and the change of estrogen receptors.:The Effect of Tamoxifen and the Change of Estrogen Receptors

概要

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Male Sprague-Dawley rats were given a single intraperitoneal injection of diethylnitrosamine (DEN, 200mg/kg body weight). Two weeks later the rats were divided into 4 groups, which were fed olive oil, diethylstilbestrol (DES, 0.5mg/day), tamoxifen (TMX, 1.0mg/day) or both DES and TMX for 8 months. The rats fed DES developed grossly visible hepatic tumors. On the other hand, tumor development was significantly inhibited in the rats fed both DES and TMX. Quantitative analysis of γ-glutamyl transpeptidase positive foci indicated that the promoter action of DES was significantly inhibited by TMX. Estrogen receptors (ER) contents of liver cytosol were significantly larger in the rats fed DES than the rats fed olive oil and smaller in the rats fed TMX or both DES and TMX than the rats fed olive oil. On the other hand, ER contents of liver nuclei were significantly larger in the rats fed TMX or both DES and TMX than the rats fed olive oil or DES. These results suggest that the promoter action of DES and inhibitory action of TMX to it are, at least in part, mediated by ER in the hepatocarcinogenesis in the rat.
財団法人日本消化器病学会の論文