Hormone Therapy

abiraterone

antagonist of testosterone

current prostate cancer treatment

ethinyl estradiol

agonist of estrogen

oral contraceptive

agonist

biological mimic, similar to a natural compound

occupies active site and triggers a response

like a master key

antagonist

Blocks the action of a natural substrate

Not usually as close a mimic

Binds to active site but not well enough to trigger a response

Like chewing gum in a lock

diethyl stilboestrol

agonist of estrogen

similar carbon framework and O functionality

tamoxifen

antagonist of estrogen

similar carbon framework

prodrug

breast cancer drug

tamoxifen synthesis

ketone undergoes SN2 reaction to add antagonistic property

than undergoes a grignard reaction

tamoxifen mode of action

normal:

estrone / estrogen agonist binds, receptor changes shape

receptor binds DNA alongside a coactivator, genes are activated and proteins are released, changes cell behaviour

tamoxifen:

binds, a response is not triggered as estrogen is blocked from binding

estrogen can still bind DNA but coactivator cannot bind receptor so no genes are activated and no proliferation proteins produced