title: Induction of pituitary tumours by combination of oestrogenic hormones and 90Sr.
abstract: The present investigation was initiated to analyse the carcinogenic effect of combined treatment with 90Sr and oestrogenic hormones or corticosteroids in inbred CBA mice. Pituitary tumours appeared in a remarkably high incidence in mice treated with oestrogens + 90Sr in low doses--0.925 kBq/g body weight (44%) and 1.850 kBq/g body weight (37%)--as compared with mice treated with 90Sr only--1 and 3 per cent, respectively. The syncancerogenic effect is ascribed the oestrogen induced proliferation of pituitary cells and their increased sensitivity to radiation. The reverse relation found between number of pituitary tumours and dose of 90Sr in oestrogen treated mice is explained by the reduction of the survival time with increasing dose. Preneoplastic histologic changes of the pituitary are described and pituitary tumours which mainly appeared in pars distalis, are classified according to the growth and tinctorial characteristics.
mesh_terms: D000239:Adenoma, Acidophil / Q000209:etiology / Q000473:pathology; D000238:Adenoma, Chromophobe / Q000209:etiology / Q000473:pathology; D000818:Animals; D004958:Estradiol / Q000031:analogs & derivatives / Q000494:pharmacology; D004967:Estrogens / Q000494:pharmacology*; D006965:Hyperplasia; D008297:Male; D008775:Methylprednisolone / Q000494:pharmacology; D051379:Mice; D008808:Mice, Inbred CBA; D009374:Neoplasms, Experimental / Q000209:etiology / Q000473:pathology; D009943:Organophosphorus Compounds / Q000494:pharmacology; D010902:Pituitary Gland / Q000473:pathology*; D010911:Pituitary Neoplasms / Q000209:etiology* / Q000473:pathology; D013326:Strontium Radioisotopes / Q000009:adverse effects*
chemical_list: D004967:Estrogens; D009943:Organophosphorus Compounds; D013326:Strontium Radioisotopes; D004958:Estradiol; C008958:polyestradiol phosphate; D008775:Methylprednisolone