A hormone that can lead to fainting and long hospital stays. I speak of my poor girlfriend's scary experience.
After getting sick from eating something and vomiting a bit, she tried to sleep. The next day, when she tried to get up, she was still vomiting and couldn't keep down water. She was walking out of the bathroom and fainted. She hit her head and had a nice welt. Well, we took her to a walk-in clinic and they said since she passed out, she should go to the emergency room. I am sure everyone knows how quick those can be. To keep this brief and to leave out the sob stories of poor service in hospitals, I will try to explain the diagnosis. (What i remember.)
The doctor said that her brain releases too much ADH. This in turn keeps her electrolytes out of equilibrium, kind of similar to a state of dehydration, with respect to the low level of electrolytes in her. It is not a major concern, she is kind of like a camel, cause she hardly ever drinks. They did suggest that she drink Gatorade or one of those other sport-drinks, instead of water. She also tends to eat foods higher in sodium to make sure there is enough in her system, but she was like that to start with.
Which makes me wonder about that thing people say where if you crave a food, it usually is because your body knows it is deficient in some part of that food. Of course, we could exclude chocolate. I don't think endorphins can be deficient.