Isn't nitrotain anabolic horsey paste?
Anyways, EVERY anabolic affects the hpta. Some more than others. However, primo at around 200mg/week should allow your hpta to function and still retain mass better than without any gear. However, don't expect to gain anything on that. Oxandrolone is good for bridging as well, somewhere in the 20mg/day range.
However, the purpose of a bridge is not a light cycle. It's to retain your gains and allow your hpta to recover. That's it.