Effects of serial passage on the endocrine response and steroid metabolism of a rat mammary carcinoma.
A rat mammary carcinoma induced by 7-12 dimethylbenzanthracene was serially transplanted into successive generations of thymectomized host animals. After its 2nd passage, the growth of the tumour appeared hormone-dependent, regressing after oophorectomy and regrowing with administration of oestradiol 17 beta to the host. Third-generation transplanted tumours, however, showed only a transient regression after oophorectomy, and the growth of tumours after further passages appeared ovary-independent. Loss in hormone dependency was not accompanied by histological changes. There was however a progressive increase with successive transplantation in the ability of tumours to metabolize 7 alpha [3H] testosterone in vitro. This was accounted for by raised conversion to 5 alpha androstanediol.
D015127:9,10-Dimethyl-1,2-benzanthracene; D000818:Animals; D002369:Castration; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D008325:Mammary Neoplasms, Experimental / Q000139:chemically induced / Q000378:metabolism*; D009368:Neoplasm Transplantation; D051381:Rats; D011919:Rats, Inbred Strains; D013739:Testosterone / Q000378:metabolism*; D013934:Thymectomy; D014185:Transplantation, Isogeneic
D013739:Testosterone; D004958:Estradiol; D015127:9,10-Dimethyl-1,2-benzanthracene