Masculine traits are a result of two types of receptor binding to androgen molecules.
- In the first type, the receptors don't have any effect on the gene expression via any method and has more of a temporary androgen dependent effect, like
- Muscle Development, because it's easier to store androgens which bind to proteins in muscles which just so happens to be a storage house of proteins like creatinine. (Estrogens are easily stored in fat cells, because why not. Their structure closely resemble lipids like their precursor cholesterol and can dissolve in lipid storing cells. And then there's aromatase storing too there).
- Libido and male aggression, where androgens kind of have an effect that can trigger required neurotransmitters for this kind of effects. (Androgens aren't the only hormones that affect neurotransmitters to make people aggressive. We have things like cortisol, and adrenaline. An opposite effect is observed due to estrogens which bind to same receptors as androgens, progestogens which compete with cortisols for receptor binding sites, and norepinephrine that competes with adrenaline. Other hormones that affect neurotransmitters are melatonin, insulin, etc.)
- Sebum and texture of stratum coreneum, which is temporarily affected by the messed up lipid barrier of the skin, because androgens don't like lipids. They like proteins and thus the skin becomes stiff and rough and dry, which the sebaceous glands try to improve by increased sebum production, but fail to do so.
- Erections
- Bone density (and not bone shape and size)
- In the second type, the receptors affect the gene expression inside the cells giving a more permanent and androgen independent effect, like
- Facial hair and body hair
- Bone shape and size (estrogens also have permanent effects here)
- Shape of eyebrows and nose (estrogens also have permanent effects here)
- Voice deepening
- Size of penis
Gene expression:
When an individual is born, he/she is programmed with a set of bodily changes that'll be observed at a certain age or on exposure to certain substances. The information of these changes is stored in the genes. Now, these genes can only be expressed when they are first transcribed and then translated.
The above changes mentioned under gene expression happen after male puberty when respective receptors are exposed to androgen molecules.
Now, in order to stop the gene expression until puberty, the DNA molecule is folded in such a way that the transcription enzymes can't bind to the gene and form its respective RNA molecule. Exposure to androgen molecules makes the DNA unfold permanently in such a way that the gene is exposed to the transcription enzymes. These enzymes bind to the gene, transcribe it, form RNA, RNA translates in ribosome, proteins are formed and gene is expressed.
Since the unfolding is permanent, the masculinization is permanent.
That means Spironolactone or any anti-androgen can't change anything and surgery is necessary for a change, unless you can affect gene expression. Bicalutamide has corepressor function, and it prevents the transcription enzymes from binding to the DNA temporarily. Thus, RNA is not formed and gene expression is halted. Dioxin reverses the unfolding of DNA and folds it again permanently.
So, there is no way you're gonna see reversal of any of the masculine traits mentioned under the gene expression category.
As for the first category, it's not considered as feminizatiom at all. And particularly, Spironolactone is a very weak anti-androgen, so you'll see no change except sebum production, but that's not because of its anti-androgenic effects, I presume, because you'll still have rough and dry skin.
