Diva, I just wanted to clarify something:
Adrenaline pumps when the parasympathetic nervous system is working - that's your fight or flight response. Certain body functions go into a 'freeze', diverting blood flow to only the vital organs so that you can theoretically 'flee' the danger that you're telling your body you are in. Yogababy mentioned this in her post about hormones, I'm just going over it in terms of the parasympathetic nervous system and the function it performs.
Endorphins are released within the sympathetic nervous system, and because the parasympathetic and sympathetic never operate simultaneously, never the twain ought to meet, so to speak. The sympathetic nervous system gets your digestion going, blood flowing etc.
During sex and childbirth (funny how they're related, but pregnant women are not allowed to be sexy!!) both systems do a little dance where they take it in turns to work. It's endorphins for most of it, then right at the end (orgasm and baby expulsion) adrenaline kicks in to finish off the job. And you don't need to work on getting the adrenaline working, it will happen by itself if there's no drug intervention (same for endorphins - drugs interfere with their production by replacing them, it's like sending in drones so that the real thing has no job anymore cos the drones take over). The endorphins, in an age where childbirth stories are riddled with fear and horror messages, need a bit more coaxing and training to come out - hence CalmBirthing and HypnoBirthing and preggy yoga practice etc!
I just thought I'd give you a bigger picture of the adrenaline an endorphin exchange, so that you can have more faith that no matter how big that gland, it can't hurt you while endorphins are playing...kind of like sharks won't hang around where dolphins are, if that helps!
Geez, second year psych has really come in handy!