I was rereading All-Star Superman #4 last night, where Superman is affected by the Black Kryptonite from the Underverse. At first, Superman is unafraid of it because he has been immune to Green Kryptonite for some time. I didn't catch this the first time I read it...does this immunity come from Lex Luthor's actions in the first issue, or is he referring to what happened in Superman #233?
I guess I'll need to reread the first issue to make sure, but I don't remember Superman being unaffected by Kryptonite radiation in #1.