When a male cat gets neutered, does he still have lots of male hormones?

My cat is 1 1/2 old and is a neutered male who acts like a tom cat sometimes. I bring him outside on a harness and he prowls around the neighborhood looking for birds and mice. He is very persistant about wanting to go outside, so I bring him out a few times a day. What is it with him behaving like a tom cat? Is it hormones?