Junk Energy Drink is a fictional brand in GTA V. It is much like real life energy drink companies such as Monster Energy or Red Bull. The term Adrenaline Junkies is one of many references to Junk Energy Drink.
Going to their webpage in-game will lead you to a link that shows all the stunt jumps over San Andreas.
As written from their webpage in game. "We have rooms full of advertising wonks whose only job is to come up with these slogans, because we are passionate about the under-25 demographic and their reckless lifestyle. You're the social media generation. You don't work hard but you play hard. You care about self expression but have no idea what it means."