As I posted several weeks ago; India has several fast growing mammary tumors. I keep thinking that there is something we aren't putting together, because rats are frequently used as test models in human studies. So I began to look around...
I came across several studies that pointed to prolactin, rather than estrogen as the hormone driver for some human mammary tumors. Prolactin also seems to drive pituitary tumor growth. Then I came across a study of (100?) rats that died with mammary tumors. The necropsy showed that most had pituitary tumors as well, even though small and not yet showing symptoms ( I was interrupted and now can't find this). Another study showed good results giving Cabergoline after mammary tumor removal to prevent reoccurring tumors.
Cabergoline acts to inhibit the release of prolactin and gonadrotopin (sp?). I also found this drug on-line. It seems to be used by body-builders. Brand names include: Dostinex, Galastop(in UK), Cabasar. This drug was given to rats every 3 days.
Bromocriptine, which BigBen and others have used to slow PT growth, also has a UK product called Pergolide (?). Some tumors have been shown to be resistant to this drug. The side effects may make this drug less tolerated by rats, and it has to be given twice a day.