Morgan R G, Papadimitriou J M, Crass R A
Department of Physiology, University of Western Australia.
Int J Exp Pathol. 1990 Aug;71(4):485-91.
In the rat, when pancreatic growth is stimulated there is an increased incidence of spontaneous pancreatic neoplasms and marked potentiation of the pancreatic carcinogen azaserine. Since previous studies showed that cholestyramine caused pancreatic growth in this species we have now studied the effect of azaserine in rats fed soya flour diets containing cholestyramine. Two groups, each of eight rats, were fed either heated soya flour (HSF) or raw soya flour (RSF). Two further groups, each of 12 rats, received the same diets containing 2% cholestyramine (HSF + C, RSF + C). In each group, four rats received azaserine (30 mg/kg i.p.) and the remainder saline, weekly, for the first 5 weeks. Animals were killed after 24 weeks and pancreatic growth and the number and size of pancreatic neoplastic nodules was measured. RSF caused a significant increase in pancreatic weight, protein, RNA and DNA, compared with HSF and cholestyramine caused a further significant increase in pancreatic weight, protein and RNA but not DNA. Azaserine did not affect pancreatic growth. In azaserine-injected rats significantly more nodules were seen and the nodules were larger and the tumour burden greater in rats fed HSF + C than in rats fed HSF alone. However, the nodule count and other nodule parameters were not significantly different in RSF and RSF + C fed rats. It is concluded that 2% cholestyramine enhances pancreatic growth when added to soya flour diets and in rats fed HSF it potentiates the action of azaserine on the pancreas. It does not increase the potentiation of azaserine seen with RSF up to 24 weeks.
在大鼠中，当胰腺生长受到刺激时，自发性胰腺肿瘤的发生率会增加，并且胰腺致癌物偶氮丝氨酸的致癌作用会显著增强。由于先前的研究表明消胆胺会导致该物种的胰腺生长，我们现在研究了偶氮丝氨酸对喂食含消胆胺大豆粉日粮的大鼠的影响。将两组，每组八只大鼠，分别喂食加热大豆粉（HSF）或生大豆粉（RSF）。另外两组，每组12只大鼠，接受相同的日粮，但添加2%的消胆胺（HSF + C，RSF + C）。在每组中，四只大鼠每周腹腔注射偶氮丝氨酸（30 mg/kg），其余大鼠注射生理盐水，持续5周。24周后处死动物，测量胰腺生长情况以及胰腺肿瘤结节的数量和大小。与HSF相比，RSF导致胰腺重量、蛋白质、RNA和DNA显著增加，消胆胺使胰腺重量、蛋白质和RNA进一步显著增加，但对DNA没有影响。偶氮丝氨酸不影响胰腺生长。在注射偶氮丝氨酸的大鼠中，喂食HSF + C的大鼠比仅喂食HSF的大鼠出现的结节明显更多，结节更大，肿瘤负荷也更大。然而，喂食RSF和RSF + C的大鼠的结节计数和其他结节参数没有显著差异。结论是，在大豆粉日粮中添加2%的消胆胺可促进胰腺生长，在喂食HSF的大鼠中，它增强了偶氮丝氨酸对胰腺的作用。在长达24周的时间里，它并没有增加RSF所观察到的偶氮丝氨酸的增效作用。
