Testosterone is a steroid hormone that is an important component of the development of male sex characteristics. This hormone is secreted from the testes in men and ovaries in women. Small amounts are secreted from the adrenal gland. Testosterone is also known as C19-H28-O2. This formula provides information relating to the number of carbon, hydrogen and oxygen atoms in testosterone. This androgen hormone contains three 6-carbon rings and one 5-carbon ring.
Synthesis
Since testosterone is a steroid hormone, it is derived from cholesterol. The biosynthesis of testosterone from choleserol is a multi-step process involving many intermediate compounds and enzymes. The majority of testosterone is produced by the testes in men. Small amounts are produced by the ovaries and placenta in women.
Hydroxyl Group
A hydroxyl group (-OH) is present at carbon-17 (C17) on testosterone. This functional group has fostered the development of synthetic forms of testosterone that can be used as therapeutic treatment for patients who have low testosterone levels.
Esterification
The process of esterification substitutes an acid group in place of the hydroxyl group. This process makes the testosterone molecule less soluble in water. This is useful for medicinal purposes, since a less soluble compound can be used in a time-release manner.
Alkylation
Alkylation of a steroid molecule involves replacing the hydroxyl group with a methyl (-CH3) or ethyl group (-C2H). Due to the addition of these functional groups, the compounds can be digested. Thus, alkylation allows the development of an oral medication.
Regulation
The synthesis and secretion of testosterone is based on a feedback mechanism. When testosterone levels are low, signals are sent to the pituitary gland in brain stimulating the release of two additional hormones: luteinizing hormone, LH, and follicle stimulating hormone, FSH. These hormones stimulate the Leydig cells of the testes to produce testosterone. As testosterone levels rise, stimulation to the pituitary gland ceases, LH and FSH are no longer released, and secretion of testosterone ceases. This pathway is known as a negative feedback loop.
References
- Greenspan, Francis S. and Gardner, David G., eds., Basic and Clinical Endocrinology, 2004.
- National Institutes of Health; Medline Plus: Testosterone
