• Question: Why do women not have testosterone

    Asked by joecall234 to Elaine on 18 Jun 2013.
    • Photo: Elaine Marshall

      Elaine Marshall answered on 18 Jun 2013:

      Women do have testosterone (T) but at a fraction of the circulating level of men. The most famous (if you like ) of the sex steroid found in woman are oestrogen (E) and progesterone (P).

      In woman the ovaries are the main source of T but it is also made locally in cells through the presence of metabolizing enzymes in specific cells, especially in the uterus. We can track which cells respond to T by staining tissue for the correct receptor (androgen) and we see that this changes with time. In poly-cystic ovary syndrome, woman have excess circulating levels of T and develop some male characteristics (facial hair etc).

      Our studies show that T plays an extremely important role in our bodies and may be key to regulating how our wombs respond throughout the menstrual cycle. You will be aware that E and P peak and trough during the woman’s period but each drive a different process. E is responsible for regeneration the womb lining (endometrium) after mensus (the shedding of the endometrium/ a period) this is highest during the first half of the menstrual cycle then dips mid cycle to very low levels when ovulation occurs. At the same time P start to rise and this drives differentiation as the endometrium prepares for implantation of a fertilised embryo. Towards the end of the cycle if there is no pregnancy then P falls and this is the signal for mensus (i.e the woman gets here period). What is interesting is that throughout this whole cycle T remains relatively constant though may rise slightly right in the middle of the cycle at the time of ovulation. During the first few days of a woman’s period the hormone which is at the most abundant level in the endometrium is T. Our work and those by others now suggest that the presence of T is preparing the cells to respond to E and helping maintain a healthy balance through out the cycle of regeneration and differentiation.

      T in woman is very important but it’s levels are tightly controlled and have a very local effect.

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