Androgen Insufficiency and Female Sexual Motivation

It is accepted that the androgen hormone regulates male sexuality while estrogen is thought to be more psychologically influential in female sexuality. However, researchers have hypothesized about the role androgen plays in regulating female sexuality, suggesting that androgens may actually regulate the degree to which estrogen is available.

At present, there is no clear evidence how an androgen insufficiency might affect a woman’s sexual desire. There is no specific “normal” range for androgen levels in women and no agreement among researchers concerning which androgens are important or connected with androgen insufficiency.

Kim Wallen, Emory University, offered new insights into the effects of androgen insufficiency during his invited address, “Androgen Insufficiency in Females: When Enough is Enough,” at the APS Annual Convention in Atlanta.

In humans, Wallen said, researchers have consistently documented that sexual behavior is highly socially regulated with strong cultural conventions. Instances of sexual behavior, rather than sexual desire, are typically used in human research to measure sexual functioning. Wallen said there is reason to suspect that such measurement is inappropriate.

A landmark paper in the 1950s (Waxenberg, Drellich, and Sutherland, 1959) concluded that adrenal function is not critical to female sexuality. The authors based this conclusion on the finding that the incidence of sexual intercourse had not declined in female cancer patients who had undergone ovariectomies. It was also reported in this study that 75 percent of those patients reported a decrease in sexual desire.

Although the drop in sexual desire was originally overlooked, later research again raised questions about the role of the ovaries in sexual functioning. As Wallen pointed out, it has been demonstrated that the initiation of sexual behavior is sensitive to ovarian cycle phase in women (initiating more sexual contact during the ovulation phase). Men, however, initiate sexual activity independently of the phase in the cycle. The ovaries produce several hormones, but the determination of which specific androgens contribute to fluctuations in desire is less clear.

Not to be easily thwarted from an area in need of sound research, Wallen has drawn from models of primate sexuality to better understand the often-cited problem of hypoactive sexual desire in women with androgen insufficiency. In primate communities, which are typically female-centered and controlled, female sexual initiation is strongly correlated with estradiol, an estrogen hormone. Females that have been ovarictomized rarely approach, or have contact with, males. The estradiol treatment approach has lead to increased sexual behavior.

Wallen has built upon Burke and Anderson’s 1972 work that found androgen to be an estrogen amplifier when it is used in conjunction with SHBG (a blood-borne protein that binds steriods). His primate research reveals what he terms, “a dynamic relationship between estrogen and androgen.” In essence, androgens regulate levels of SHBG and the bio-availability of estrogen.

Wallen’s research also reveals that estrogen treatment alone will not be effective at resolving hypoactive sexual desire. Similarly, androgen treatment alone will only be effective at very high doses. A combined treatment of estrogen and androgens lowers SHBG and increases the free estrogen. One arousing (!) implication of this work is that androgens could be given to women allowing them greater control over the timing of sexual desire.

REFERENCE
Waxenberg, S E, Drellich, M G, and Sutherland A M. (1959) The role of hormones in human behavior. I. Changes in female sexuality after adrenalectomy. Journal of Clinical Endocrinology and Metabolism, 19: 193-202.