Gender Differences: Testosterone Production, Receptors, Blood Levels, and Activity

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Genetics program each cell with receptors for Testosterone and how they will respond to the hormone.

My medical practice and my research is based on the basic need for the hormone testosterone in both men and women as they age.  We have plenty of this hormone when we are young, and it is the factor that makes us look and feel youthful.  As we age, after 40 for women and 50 for men we lose our testosterone which then causes our growth hormone and other metabolic systems to malfunction.  The path is short between low testosterone and sickness.   Today I want to discuss the differences between the blood levels of testosterone between the sexes and compare every other action and effects of testosterone between genders.

Let me lay some ground work.  Genetics program each cell with receptors for T and how they will respond to the T hormone, when it is present.  This is the first factor in the difference between how T works in each sex.  The second factor that affects Testosterone activity is how T competes with estrogen, and how estrogen decreases the Free Testosterone levels in both men and women, but women have a lot more E2 and much less Testosterone which leaves women with dramatically lower free T blood levels.  This brings us to the difference in amount of T that is produced in men and women.  Lastly, women only produce testosterone from their ovaries until menopause when their ovaries “die” and atrophy.  Men’s testicles never atrophy, but just make less T with age.  It is all of these factors that affect the difference between the genders in how they express testosterone hormone effects.

Factors Affecting the Differences in the Effects of T on the Genders
How T Competes with Estrogen and how Estrogen inactivates T
Steady production or Cyclic production
Amount of T produced
Organs that Produce T
How Production Decreases with Age
Age of Symptom Appearance
The Effect Of T OnvSexual Function

The differences between how men and women MAKE testosterone is key to understanding the gender differences. Both men and women make the precursors of T in the adrenal gland, DHEAS and Pregnenalone, which are transported to the testes in men and ovaries in women.  In these two very different organs genetics drives the production of testosterone. Testosterone is very low in childhood and begins to be secreted by these two organs at puberty, sexual maturity.  At this point the difference in genders is that the testicle makes ten times as much T and the ovary does, and the testicle makes the same amount of T daily in mature men, but in women, T is made right before ovulation and for the second half of the 28-day cycle until menopause, so in women, T is cyclic in its production.

T made in the Testes T made in the Ovaries
10-12 mg T produced a day 1-2 mg T is produced a day
Production is steady state Production is Cyclic
Testosterone is produced
throughout Life after puberty
Testosterone production stops at
Low T symptoms occur after age 50 Low T symptoms occur after age 40
Men’s receptors are genetically
more sensitive to T
Women’s receptors are genetically
less sensitive to T
Men have very low E2, E1 and
much higher Free T per total
T circulating
Women have high E2/E1 and a
much lower Free T per total
T circulating
Men have low E2, therefore their
receptors are not clogged with
estrogen, so T becomes more
Women have high E2, therefore their receptors are clogged up with estrogen that compete for receptors, therefore blood levels of free T do not have the same effect as it does in men.
Men have higher conversion to
DHT and more facial hair and
balding and bigger muscles
Women have lower conversion of T to DHT so they have less facial
hair and balding and smaller
Men have more sensitive receptors for DHT Women have less sensitive receptor sites for DHT

This Health cast was written and presented by Dr. Kathy Maupin, M.D., Bio-identical Hormone Replacement Expert and Author, with Brett Newcomb, MA., LPC., Family Counselor, Presenter and Author.

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