Greetings,

I’m an analytical chemist, I’m currently working on androgenic steroids. I have basic knowledge in biology and biochemistry but not enough in the subject I’m currently working on. Anyway, I have this steroidogenesis pathway on which I’m basing my research and I’ve succeeded in identifying all of the androgens that are mentioned. However, I’m still confused when it comes to two molecules. See in the image below there are two molecules, 4-DIONE and A-DIONE. Which of the two is Androstenedione? What’s the difference between the two? Can anyone provide molecular structures or ideally CAS numbers?

Thanks a lot in advance!