Testosterone

low testosterone levels due to agingmetabolismprenatal exposure to androgensserum testosteronesteroid hormonetestosterone congenerstestosterone levelstestosterone-powered
Testosterone is the primary male sex hormone and an anabolic steroid.wikipedia
1,058 Related Articles

Male

malesmasculine
Testosterone is the primary male sex hormone and an anabolic steroid.
Most male mammals, including male humans, have a Y chromosome, which codes for the production of larger amounts of testosterone to develop male reproductive organs.

Androgen receptor

androgen receptorsARandrogen
It exerts its action through binding to and activation of the androgen receptor.
The androgen receptor (AR), also known as NR3C4 (nuclear receptor subfamily 3, group C, member 4), is a type of nuclear receptor that is activated by binding any of the androgenic hormones, including testosterone and dihydrotestosterone in the cytoplasm and then translocating into the nucleus.

Androgen

androgensandrogenicAndrogenic steroid
The major androgen in males is testosterone.

Beard

five o'clock shadowbeardsfull beard
Pubic hair extends to thighs and up toward umbilicus, development of facial hair (sideburns, beard, moustache), loss of scalp hair (androgenetic alopecia), increase in chest hair, periareolar hair, perianal hair, leg hair, armpit hair.
Dihydrotestosterone is produced from testosterone, the levels of which vary with season.

Dihydrotestosterone

5α-DihydrotestosteroneDHT17-hydroxyandrostan-3-one
Examples include genital virilisation such as midline fusion, phallic urethra, scrotal thinning and rugation, and phallic enlargement; although the role of testosterone is far smaller than that of dihydrotestosterone.
The enzyme 5α-reductase catalyzes the formation of DHT from testosterone in certain tissues including the prostate gland, seminal vesicles, epididymides, skin, hair follicles, liver, and brain.

Osteoporosis

bone lossosteoporoticpostmenopausal osteoporosis
In addition, testosterone is involved in health and well-being, and the prevention of osteoporosis.

Biosynthesis

productionsynthesisbiosynthetic
It is biosynthesized in several steps from cholesterol and is converted in the liver to inactive metabolites.
Not only does it serve as a component of lipid membranes, it is also a precursor to several steroid hormones, including cortisol, testosterone, and estrogen.

Sex steroid

sex hormonesex hormonessex steroids
Testosterone is the primary male sex hormone and an anabolic steroid.
In many contexts, the two main classes of sex steroids are androgens and estrogens, of which the most important human derivatives are testosterone and estradiol, respectively.

Puberty

pubescentpubescencesexual development
For boys, the androgen testosterone is the principal sex hormone; while testosterone is produced, all boys' changes are characterized as virilization.

Body hair

androgenic hairpilositybody
In male humans, testosterone plays a key role in the development of male reproductive tissues such as testes and prostate, as well as promoting secondary sexual characteristics such as increased muscle and bone mass, and the growth of body hair.
Hair follicles are to varying degrees sensitive to androgen, primarily testosterone and its derivatives, particularly dihydrotestosterone, with different areas on the body having different sensitivity.

Libido

sex drivesexual desirelibidinal
Growth of spermatogenic tissue in testicles, male fertility, penis or clitoris enlargement, increased libido and frequency of erection or clitoral engorgement occurs.
Biologically, the sex hormones and associated neurotransmitters that act upon the nucleus accumbens (primarily testosterone and dopamine, respectively) regulate libido in humans.

Estrogen

oestrogenestrogensestrogenic
The male brain is masculinized by the aromatization of testosterone into estrogen, which crosses the blood–brain barrier and enters the male brain, whereas female fetuses have α-fetoprotein, which binds the estrogen so that female brains are not affected.
All of the different forms of estrogen are synthesized from androgens, specifically testosterone and androstenedione, by the enzyme aromatase.

Clitoris

clitoralclitoral glansglans clitoridis
Growth of spermatogenic tissue in testicles, male fertility, penis or clitoris enlargement, increased libido and frequency of erection or clitoral engorgement occurs.
The Y chromosome contains a sex-determining gene (SRY) that encodes a transcription factor for the protein TDF (testis determining factor) and triggers the creation of testosterone and Anti-Müllerian hormone for the embryo's development into a male.

Testosterone and the cardiovascular system

testosterone in maintaining cardiovascular health
Conflicting results have been obtained concerning the importance of testosterone in maintaining cardiovascular health.
The predominant androgen in men, testosterone, has shown to substantially decline throughout the aging process.

Seminal vesicle

seminal vesiclesvesicula seminalisvesicular gland
There is also development of the prostate gland and seminal vesicles.
The seminal vesicles contain 5α-reductase, which metabolizes testosterone into its much more potent metabolite, dihydrotestosterone (DHT).

Anabolic steroid

anabolic steroidsanabolic-androgenic steroidanabolic–androgenic steroid
Testosterone is the primary male sex hormone and an anabolic steroid.
Androgens such as testosterone, androstenedione and dihydrotestosterone are required for the development of organs in the male reproductive system, including the seminal vesicles, epididymis, vas deferens, penis and prostate.

Estradiol

17β-estradioloestradiol17-β-estradiol
This occurs indirectly via estradiol metabolites and hence more gradually in men than women.
Alternatively, androstenedione can be converted into testosterone, which can then be converted into estradiol.

Steroid

steroidssteroidogenesisbiosynthesis of steroids
Testosterone is a steroid from the androstane class containing a keto and hydroxyl groups at the three and seventeen positions respectively.
Examples include the lipid cholesterol, the sex hormones estradiol and testosterone, and the anti-inflammatory drug dexamethasone.

Digit ratio

2D:4D finger ratiosdigit-length ratiofinger length ratio
Higher pre-natal testosterone indicated by a low digit ratio as well as adult testosterone levels increased risk of fouls or aggression among male players in a soccer game.
The ratio of two digits in particular, the palmar 2nd (index finger) and 4th (ring finger), is affected by exposure to androgens, e.g., testosterone while in the uterus and that this 2D:4D ratio can be considered a crude measure for prenatal androgen exposure, with lower 2D:4D ratios pointing to higher prenatal androgen exposure.

Sertoli cell

Sertoli cellsSertoliname
It activates genes in Sertoli cells, which promote differentiation of spermatogonia.

Growth hormone

human growth hormoneHGHgrowth hormones
Growth of jaw, brow, chin, and nose and remodeling of facial bone contours, in conjunction with human growth hormone occurs.

Hypoactive sexual desire disorder

frigiditydecreased libidoloss of libido
Therefore, these mammals may provide a model for studying clinical populations among humans suffering from sexual arousal deficits such as hypoactive sexual desire disorder.
In the case of acquired/generalized low sexual desire, possible causes include various medical/health problems, psychiatric problems, low levels of testosterone or high levels of prolactin.

Alpha-fetoprotein

AFPalpha fetoproteinα-fetoprotein
The male brain is masculinized by the aromatization of testosterone into estrogen, which crosses the blood–brain barrier and enters the male brain, whereas female fetuses have α-fetoprotein, which binds the estrogen so that female brains are not affected.
Gonadal hormones from the testes, such as testosterone and antimullerian hormone are required to cause development of a phenotypic male.

Prostate cancer

prostatehormone-refractory prostate cancermetastatic prostate cancer
Testosterone does not appear to increase the risk of developing prostate cancer.
Finally, obesity and elevated blood levels of testosterone may increase the risk for prostate cancer.

Congenital adrenal hyperplasia

adrenal hyperplasiaadrenogenital syndromeadrenal hyperplasia, congenital
Among women with CAH, a male-typical play in childhood correlated with reduced satisfaction with the female gender and reduced heterosexual interest in adulthood.
Synthesis of cortisol shares steps with synthesis of mineralocorticoids such as aldosterone, androgens such as testosterone, and estrogens such as estradiol.