i think the theory is that certain muscles have a greater number of androgen receptors and so they are more susceptible to steroid induced changes...
Bros-- True it is about muscle receptors, but not the way you think:
1--- There are many different receptor (proteins) on the
sarcolemma (outer muscle membrane) that influence muscle in a number of ways. For instance, receptors often can predict
muscle strength (eg. the acetylcholine receptor interacts with the chemical neurotransmitter acetylcholine. When a patient has myasthenia there is an autoimmune attack against AChRs and
thus too few AChRs so the patient becomes weak and fatigues
rapidly. We see this to some extent normally in ourselves-- why can't you do more than twenty reps when benching 2 plates on one side???)
2- Use of muscle influences receptor number as do other hormones, transmitters. For instance, thyroid can influence the number of beta-adrenergic receptors as well as numbers of AChRs. Ever wonder why someone on roids who does not exercise look like shit, yet someone who lifts has a better physique?
3- Androgens interact with their very own receptors in muscle, yet they can upregulate other receptors simultaneously. Yep they influence AChRs and this can make you stronger-- exercise increases this interaction and BINGO muscle hypertrophy--- but for only specific fibers-- type 1// type 2.
4- The internal nuclei in a muscle fiber have nothing to do with it-- in fact the presence of internal nuclei in a muscle biopsy is "myopathic" and is indicative of muscle disease. Use of corticosteroids-- predisone-- can cause this and because of it's effect on receptors lead to a Type 2 fiber atrophy and muscle weakness if taken for long periods.
DOC
Lift, fuck, make money