Lu S, Lee W M, Archer M C
Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Canada.
Carcinogenesis. 1998 Apr;19(4):699-702. doi: 10.1093/carcin/19.4.699.
Indirect evidence from both epidemiological studies and animal experiments suggests that insulin may promote breast cancer development. In this study, we directly tested for a promoting effect of insulin on mammary carcinogenesis in Sprague-Dawley rats. Fifty day-old female rats received an i.p. injection of 37.5 mg/kg methylnitrosourea (MNU). Five days later, the animals were randomized into two groups. One group received insulin injections five times/week until the time of death, while the other control group received similar injections of normal saline. Over the course of 26 weeks following MNU treatment, the mammary tumour incidence in the insulin-treated group did not differ significantly from the saline-treated controls. Furthermore, the number of tumours per tumour-bearing rat did not differ between groups. Our results demonstrate that insulin is not a promoter of mammary carcinogenesis in this model.
流行病学研究和动物实验的间接证据均表明，胰岛素可能促进乳腺癌的发展。在本研究中，我们直接测试了胰岛素对斯普拉格-道利大鼠乳腺致癌作用的促进效果。50日龄雌性大鼠腹腔注射37.5mg/kg的甲基亚硝基脲（MNU）。五天后，将动物随机分为两组。一组每周接受5次胰岛素注射直至死亡，而另一对照组接受类似的生理盐水注射。在MNU治疗后的26周内，胰岛素治疗组的乳腺肿瘤发生率与生理盐水治疗的对照组无显著差异。此外，每组荷瘤大鼠的肿瘤数量也无差异。我们的结果表明，在该模型中胰岛素不是乳腺致癌作用的促进因素。
