Testosterone levels with no treatment and with various estrogens in men with prostate cancer. Determinations were made with an early radioimmunoassay (RIA). Source was Shearer et al. (1973). CTA is a relatively weak estrogen, with about one-eighth the potency of DES. However, it is highly lipophilic and is stored in fat tissue for prolonged periods of time, with its slow release from fat resulting in a very long duration of action. CTA itself is inactive; it behaves as a prodrug to desmethylchlorotrianisene (DMCTA), a weak estrogen that is formed as a metabolite via mono-O-demethylation of CTA in the liver. As such, the potency of CTA is reduced if it is given parenterally instead of orally. Although it is referred to as a weak estrogen and was used solely as an estrogen in clinical practice, CTA is a high-efficacy partial agonist of the estrogen receptor. As such, it is a selective estrogen receptor modulator (SERM), with predominantly estrogenic effects but also with antiestrogenic effects, and was arguably the first SERM to ever be introduced. CTA can antagonize estradiol at the level of the hypothalamus, resulting in disinhibition of the hypothalamic–pituitary–gonadal axis and an increase in estrogen levels. Clomifene and tamoxifen were both derived from CTA via structural modification, and are much lower-efficacy partial agonists than CTA and hence much more antiestrogenic in comparison. As an example,<unk>  produces gynecomastia in men, albeit reportedly to a lesser extent than other estrogens, while clomifene and tamoxifen do not and can be used to treat gynecomastia. CTA at a dosage of 48 mg/day inhibits ovulation in almost all women. Conversely, it has been reported that CTA has no measurable effect on circulating levels of testosterone in men. This is in contrast to other estrogens, like diethylstilbestrol, which can suppress testosterone levels by as much as 96%—or to an equivalent extent as castration. These findings suggest that CTA is not an effective antigonadotropin in men.
Chlorotrianisene
Desmethylchlorotrianisene
Keldur
Phenylsilatrane
Triphenylbromoethylene
Triphenylethylene
Michellamine
Menthol