Did you accidentally cut/pop the gall bladder? Not sure if that is the correct organ name, cut it is small translucent sack like thing hidden away around under the stomach area. I use to pop it by mistake as a kid and learned you taint the tast of it from where all that yellow stuff touches the inside cavity.
If you can avoid the tinted area. If you don't believe me - set aside a piece that you cook seperately (even if you fry it in a skillet or microwave it so you can just taste it) and try it. It will make you wretch almost..... lol.
I found a pic of it here:
http://www.infovisual.info/02/033_en.html