[The production of epidermal growth factor and polypeptides similar to it in the intestinal mucosa of rats in 1,2-dimethylhydrazine-induced carcinogenesis and compensatory regeneration].

The production of EGF and EGF-like polypeptides in the normal intestinal mucosa and during 1,2-dimethylhydrazine (DMH)-induced carcinogenesis and postresection regeneration was studied in albino rats using chromatographic separation of acid-ethanol extracts. Fractions after gel filtration on Biogel P-60 with subsequent reverse-phase high performance liquid chromatography in acetonitrile gradient were tested in radioreceptor assay for competition with EGF. It has been established that intestinal tumours induced by DMH and regenerating intestinal mucosa have amplified production of EGF--alpha-TGF and related proteins of high molecular weight (approx. 30; 45-55; 120 kD) with the EGF-competitive activity. It is supposed that the high molecular weight EGF-competitive material represents nonprocessed forms of EGF and/or alpha-TGF which are accumulated in rapidly proliferating low-differentiated cells due to the intensified expression of their genes.