Let's don't get into 'purposes' for chemicals and drugs. There are no 'purposes'. They have effects, and we seek them out for their effects. That is all. It's not like these compounds have an agenda...
Mr. Lutalyse: oh noooooo, this body isn't female...this body isn't cattle...well, harumph, then I'm just going to sit here and do nothing. My purpose is inducing abortions in cattle, and that's what I'm going to do.
Sorry, but this get's old.