Testosterone

Absorption

A single 100mg topical dose of testosterone has an AUC of 10425±5521ng*h/dL and a Cmax of 573±284ng/dL. Testosterone is approximately 10% bioavailable topically.

Toxicity

Data regarding an overdose with a topical testosterone product is not readily available. In the case of overdose with an injectable product, patients may present with a cerebrovascular event. Treat overdoses by stopping testosterone products, washing off any topical products with soap and water, and initiating symptomatic and supportive treatments.

Description

Testosterone (Item No.15645) is an analytical reference material categorized as an anabolic androgenic steroid. Testosterone is an endogenous metabolite of androstenedione (Item Nos. ISO60161 | 15874) and estradiol (Item Nos. ISO60155 | 10006315). Anabolic steroids, including testosterone, have been used to enhance physical performance in athletes. Testosterone is regulated as a Schedule III compound in the United States. This product is intended for research and forensic applications.

Description

Men who complain of irritability, fatigue, and loss of libido—characteristics of andropause, a male version of menopause—are increasingly turning to testosterone replacement therapy. First reported in the mid-40s, research on this little known condition is intensifying with clinical and drug trials in progress.

The Uses of Testosterone

Secreted by the testis and is converted to dihydrotestosterone in the target tissue where is appears to mediate many of the biological actions of testosterone. CONTROLLED SUBSTANC

Background

Testosterone is a steroid sex hormone indicated to treat primary hypogonadism and hypogonadotropic hypogonadism. Testosterone antagonizes the androgen receptor to induce gene expression that causes the growth and development of masculine sex organs and secondary sexual characteristics.
Testosterone was isolated from samples and also synthesized in 1935.

Indications

Testosterone is indicated to treat primary hypogonadism and hypogonadotropic hypogonadism.

Pharmacokinetics

Testosterone antagonizes the androgen receptor to induce gene expression that causes the growth and development of masculine sex organs and secondary sexual characteristics. The duration of action of testosterone is variable from patient to patient with a half life of 10-100 minutes. The therapeutic index is wide considering the normal testosterone levels in an adult man range from 300-1000ng/dL. Counsel patients regarding the risk of secondary exposure of testosterone topical products to children.

Metabolism

Testosterone is metabolized to 17-keto steroids through two different pathways. The major active metabolites are estradiol and dihydrotestosterone (DHT).
Testosterone can be hydroxylated at a number of positions by CYP3A4, CYP2B6, CYP2C9, and CYP2C19; glucuronidated by UGT2B17; sulfated; converted to estradiol by aromatase; converted to dihydrotestosterone (DHT) by 5α-reductase; metabolized to androstenedione by CYP3A4, CYP2C9, and CYP2C19; or converted to DHT glucuronide.
Androstenedione undergoes metabolism by aromatase to form estrone, which undergoes a reversible reaction to form estradiol. Androstenedione can also be converted to 5α-androstanedione by 5α-reductase, which can be further metabolized to 5α-androsterone.
DHT can be glucuronidated or sulfated, or metabolized to 5α-androstanediol, androstane-3α,17β-diol, or androstane-3β,17β-diol. DHT can also be reversibly converted to 5α-androstanedione.