Enjoyed the roundtable, guys! Question. I understand how we come about the STRUCTURE of substances (ie various forms of Spectometry, Chromotography, etc.), but I’m confused about the important property called “activity” (NON-enzymatic; e.g. "So-and-so compound has strong anabolic and androgenic ACTIVITY…)In the realm of research, how is “activity” measured? (Just curious…I’m ALWAYS searching for greater knowledge)!
Well, initially, scientists had set out to totally separate anabolic and androgenic effects upon tissue. Well, as we know, this hasn’t happened. Anyhow, the way they measured exactly how “anabolic” and “androgenic” the steroid, was based on in vivo bioassays in male rats, where increased levator ani muscle weight occured at dosages lower than what was needed to stimulate the growth of the seminal vesicles and the prostate. In other words, if substance “A” stimulated growth of the levator ani at a VERY low dosage and had little effect on the seminal vesicles and prostate, then it was considered to be highly anabolic and not very androgenic. However, the problem with this particular bioassay is that the levator ani is not a skeletal muscle, but rather, a sexual dimorphic muscle. Now the AR itself, found in skeletal muscle, probably doesn’t differ from AR’s found in sem. ves. and the prostate. However, one difference does exist. What’s that? Well, skeletal muscle doesn’t contain 5alpha-reductase, whereas, the sem ves and prostate do. Therefore, an androgen like testosterone would be reduced to DHT (more potent) and appear to be more potent than something like nandrolone which, when reduced, doesn’t bind as well to the AR. In reallity, nandrolone binds to the AR 2-3 times better. So, essentially, the old system was botched. More recently, scientists have measured the trophic activity in skeletal muscle itself. This is the best way. The old system still has value though. Whew! I’m half asleep so hopefully that all made sense.
With androgens, most actual measurements
are of growth effects on the rat levator ani
(analogous to the pubococcygeus or “PCG”
muscle in man, not a skeletal muscle) and
rat prostate. There are no measurements,
in most cases, of skeletal muscle anabolic
activity, effect on virilization of women
with regard to voice or facial hair, effect
on hair loss, etc. It was mistakenly assumed
by scientists, back in the 50s and 60s
when anabolic steroids were being developed,
that the two above-mentioned measurements
would accurately predict therapeutic effect
vs. undesired side effects. That really is not so.
OUTSTANDING, guys! Makes sense. So like ANY substance/medicine/compound etc. that begins with in vitro then limited in vivo studies, we only REALLY begin to see the “true” effects/side effects when there is widespead use among a population (prime examples being phen-fen, and of course ,Anabolic Steroids). Is that pretty close to what happens? THANKS!