The sex hormones are divided into two major groups, androgens and estrogens (oestrogens). Traditionally, androgens where considered the "male" sex hormones and estrogens the "female" sex hormones, but both play an active and vital role in the normal function of men and women. There are three types of estrogen that have a role in over 400 bodily functions. The three types of estrogen are estrone (E1), estradiol (E2), and estriol (E3). There are five types of androgens that influence a woman’s sexual desire, mood, and energy, and are necessary for healthy bones and muscles. The five types of androgens are dihydrotestosterone (DHT), testosterone, dehydroepiandrosterone (DHEA), dehydroepiandrosterone-sulfate (DHEA-S), and androstenedione. The total amount of androgens in women is estimated to be about 71% of that of men, which is a level much greater than previously believed.
Androgen levels in girls first start to increase between the ages of six and ten, but do not reach their maximum levels until between the ages of 20 and 30. The onset of increased androgen production is referred to as adrenarche. The first visible indication of this event is the development of pubic hair, which is referred to as pubarche. The increasing level of these hormones at this young age is a possible reason why 47% of women report they experienced sexual desire prior to their first menstrual period, menarche. Menarche is unrelated to andrenarche, and a woman can experience the onset of menstruation without ever developing pubic hair. The fact that androgen levels do not peak until a woman is in her twenties may explain why 68% of women report their level of sexual desire is greater in their twenties than their teens, and why some do not experience the onset of intense sexual desire until they are in their late teens or early twenties. When a woman's level of androgen decrease to 10-20% of their peak level it is referred to as adrenopause, which is independent of menopause.
Medical Quote:
"All agree that dehydroepiandrosterone sulfate (DHEA-S) production from the adrenal gland begins during the preteen years, peaks in the mid 20s, then declines progressively over time. In contrast, ovarian androgen (i.e., testosterone) secretion commences at puberty, is sustained during a woman's peak reproductive years and declines as a woman ages, with a more rapid and steep decrease after surgical menopause. However, there are ample data to suggest that adrenal androgens play a role in the development of axillary and pubic hair, and that testosterone is critical for women's libido and sexual function."
"Interestingly, Davis et al. were unable to demonstrate a correlation between total testosterone plasma [blood] levels and symptoms of sexual function. However, good correlations were found between various parameters of sexual function and the adrenal androgen DHEA-S." [9]
Androgens are initially produced by the ovaries and adrenal glands. After which they enter the blood stream and circulate throughout the body to the tissues and organs that are sensitive to and controlled by them. The amount of estrogens and androgens in the blood, for the most part, indicate the amount of these hormones being produced by the ovaries and adrenals, but these levels do not accurately indicate the amount of these hormones within the actual tissues of the body. The amount of androgens in the blood indicate the general health, menstrual state, and functional age of the ovaries and adrenals.
Relatively recently it was discovered that the conversion of hormones into other types of hormones takes place within the individual cells that use them. As an example, the hormone DHEA is converted into testosterone during a chain of events inside some cells, within the tissues of the breast and other organs. It is now believed that the majority of the testosterone produced and consumed within the female body is done in this manner. These newly converted hormones are consumed by the cell and only the bi-products of that process enter the blood stream.
Only a small fraction of the hormones produced within the cells of the different organs enter into the blood stream where they can be measured by standard blood tests. The amount of androgen in the tissues is measured indirectly through the amount of bi-product within the blood. To determine the total amount of androgens in the body the amount of androsterone glucuronide (ADT-G), androstenediol glucuronide (3α-diol-G), and androsterone-3β (3β-diol-G) in the blood must be measured. The most reliable test methods employ radioimmunoassays; some luminometric assays are reported to be "problematic."
Androgen Levels Decrease Throughout Adulthood
As indicated by the following graphs and tables, the amount of androgens in the blood stream decrease throughout adulthood, and have decreased significantly by the completion of menopause. While the androgen output of the ovaries may have decreased during menopause, they do not decrease to zero. This is demonstrated by the fact that postmenopausal women who have had their ovaries surgically removed have significantly lower levels of androgens than women who did not.
The data presented in the above graphs and tables came from the article Androgen Levels in Adult Females: Changes with Age, Menopause, and Oophorectomy The Journal of Clinical Endocrinology & Metabolism 90(7):384-3853 April 12, 2005
Androgen Production & Circulation
The following illustrations reveal how much the ovaries contribute to the amount of androstenedione and testosterone in the blood prior to and after menopause. They also show how some of the DHEA that is converted into androstenedione and testosterone, within the cells of the body, contribute to the amount of these hormones in the blood. [8]
Prior to menopause the ovaries contribute 50% of the androstenedione present in the blood. Women who have had their ovaries removed prior to menopause may experience a 50% decrease in the amount of androstenedione in their blood, but this may not cause a significant change in the overall amount of androstenedione in their body.
After menopause the ovaries contribute 20% of the androstenedione present in the blood. Women who have had their ovaries removed after menopause may experience a 20% decrease in the amount of androstenedione in their blood, but this may not cause a significant change in the overall amount of androstenedione in their body.
The ovaries contribute about half of the amount of testosterone in the blood throughout a woman's lifetime. Surgical removal of the ovaries may result in a 50% decrease in the amount of testosterone present in the blood, but this may not cause a significant change in the overall amount of testosterone in the body. The amount of testosterone in the blood decreases by about 50% between the ages of 21 and 40. This is thought to be the result of the declining quantity of DHEA produced by the adrenals.
The following illustration demonstrates how only 10% of the testosterone present in the tissues of the body originates in the blood stream. The remaining 90% is the result of the conversion of DHEA to testosterone within the tissues of the body. DHEA must be converted into other hormones prior to its conversion into testosterone. When testosterone is converted into DHT, it is most effective.
The information contained in the four illustrations shown above came from the article Endocrine and Intracrine Sources of Androgens in Women: Inhibition of Breast Cancer and Other Roles of Androgens and Their Precursors. Endocrine Reviews 24(2): 152-182 Copyright 2003
