Well... I think it's obvious that using Dbol will shut you down, however I don't think that is what is being referred to here.
Take prohormones for example. As in, prohormones overall will impair your HPTA, but will lead to a short-lived (a matter of hours) increase in endogenous testosterone. This is what I have heard is the case with Dianabol as well. I guess I am thinking of Dbol as somewhat of a prohormone in this respect (with regards to testosterone - and please realize I don't consider Dbol to be a prohormone).
Am I making sense? I realize I could be way off-base here, but this is just what I've picked up along the way and I think it's what Nelson was saying when he said that one's serum testosterone levels will be elevated within a few hours of ingestion.
Now... I believe this because I believe Nelson and I've heard it many times. However, I know you're the study man... so please show me why/If you believe I am wrong here.
JJ