Relying on e-mail alone to communicate news releases to the media is Public Relations Malpractice.
Pick up the darn phone and make a phone call, among other things, and you'll separate yourself very rapidly from the PR pack. Sending e-mail is among the easiest acts anyone can perform. So is deleting that very same e-mail.
Don't let the ease with which you can send a blizzard of news releases blind you to the fact that it's just one step in the process of engaging reporters, editors, producers and other decision-makers.
You can read more about my approach in this previous Inside Edge PR blog post, The Art of Contacting Reporters By Phone.