Читать книгу The Ultimate PCOS Handbook: Lose weight, boost fertility, clear skin and restore self-esteem - Theresa Cheung - Страница 10

Another theory about what causes PCOS is that women with the condition produce too much testosterone – a hormone known as the ‘male’ hormone because men produce 10 times more than women. In PCOS, the excess testosterone finds its way into the body’s circulation and triggers the familiar PCOS symptoms of hair loss, facial hair and acne. Testosterone can also be converted into oestrogen in the fat stores of the body. The result: weight gain and hormonal havoc.

It appears that a malfunction with the hypothalamus–pituitary regulation of the menstrual cycle in women with PCOS causes the release of abnormal levels of hormones, in particular testosterone. Not only do high levels of luteinizing hormone (LH) stimulate the production of testosterone in the ovaries, but when the ovaries aren’t working as they should they become thickened, and this thickening produces even more testosterone.

Several studies have linked excess androgens (male hormones, including testosterone) with PCOS. Testosterone is the most often cited, but research⁶ has also suggested that PCOS may be the result of a surge of another male hormone, adrenal androgen DHEA. DHEA is responsible for the production of pubic and armpit hair in puberty. This has yet to be proved conclusively, but it’s interesting as many women with PCOS date the beginning of their problems from puberty, when male hormones first surge.

‘I was 15 when I first noticed something was wrong. My friends had mild acne, but my face exploded. My friends started their periods, but I didn’t.’

Laura, 21

Some experts believe that even you haven’t got high levels of testosterone you may become more sensitive to it if you have PCOS, and go on to develop symptoms associated with testosterone excess because of that sensitivity, rather than increased levels. This could explain why some women with PCOS don’t show high testosterone levels in blood tests, even though they have the symptoms.

Testosterone is carried in the bloodstream by a protein called sex hormone-binding globulin (SHGB). Higher-than-normal insulin levels in the bloodstream can suppress the production of SHBG so that the amount of unbound (active) testosterone is raised – the reason why some women with high insulin levels (common if you’re overweight) can have signs of testosterone excess even when tests reveal a normal level in the blood.