It is saying that zantac, starting at 65mg, increases prolactin release in a dose dependent manner, i.e., the more zantac you take the more prolactin is secreted. It does not seem to affect GH or thyroid levels. There is another antihistamine H2 blocker, cimetidine (Tagamet) that lowers testosterone levels. These don't seem to be the greatest drugs to take on a full time basis.