Effect of pituitary hormones on carcinogenesis with 9, 10-dimethyl-1, 2-dibenzanthracene in hypophysectomized rats.

T h e suppress ion of ca rc inogenes i s in h y p o p h y sec tomized a n i m a l s h a s been r e p o r t e d b y severa l i nves t i ga to r s (11, 23, 25). W e h a v e p r e v i o u s l y rep o r t e d on th i s p h e n o m e n o n in r a t s w i t h n e o p l a s m s deve lop ing d u r i n g chron ic i n j ec t i on of g r o w t h hor m o n e (21), w i t h s p o n t a n e o u s t u m o r s (21), a n d w i t h sa rcomas i n d u c e d w i t h m e t h y l c h o l a n t h r e n e (19, 20). T h e p r e s e n t s tud ies were conce rned w i t h t h e effects of c rude p i t u i t a r y ex t r ac t , g r o w t h hormone , a n d a d r e n o c o r t i c o t r o p h i c h o r m o n e on t h e ca rc inogen ic response of h y p o p h y s e c t o m i z e d r a t s to 9 , 1 0 d i m e t h y l l , 2 d i b e n z a n t h r a c e n e .