I don't think this is anything to do with hormones. This is a natural behaviour, with the younger one starting to try to take over as top dog, and the older one not having any of it. You need to decide which one is going to be top dog, and allow him to be, making the other one wait for meals, wait for a fuss etc. You cannot get them to agree if they don't want to. They will keep trying to sort it out in their own way, ending up in a right old scrap. Castration might have helped a bit when it kicks in, but I have my doubts, having kept males together for many years, and at present having two who occasionally have 'words'. I find the best method (if you can steel yourself to do it) is to walk away and totally ignore them. If you intervene even by raising your voice they are both encouraged to go for the other one, thinking that your intervention means they are doing the right thing and its what you want. Just give it a try, as soon as they look at each other funny, go out of the room and close the door, obviously listening for any escalation, but you will probably find that you leaving the room makes them stop what they were planning.