[dew3554]

I became interested in this after reading about hormonal implants.

Chemically, what gives estrogen it's estrogenic effects? What part of the molecule in the estrogen group binds to the estrogen receptor? And what part of the testosterone molecule gives testosterone it's anabolic effects?

Also, what causes two different types of these chemicals ie (Dihydrotestosterone compared to testosterone) and (Estradiol compared to estrone) it's varying effects in strength?

The two molecules are very similar, yet have polar opposite effects?

[Babcock_Hall]

There is an enormous amount of information available on the QSAR of estrogens.  You could try a search on structure activity relationships in estrogens at PubMed and limit yourself to review articles to cut down the number of citations to something manageable.

[dew3554]

 Thanks, I'll check that out, endocrinology is very interesting imo.