Well what a long and involved thread!
I am like you BrightLight - naturally curious - which is why I studied science in the first place, and still enjoy learning - which is why I enjoy being a member of this forum because I am continually being challenged to look things up that I'm not clear about (sometimes unsuccessfully!) although it all takes up a lot of time!! Having said that I finished my Biology Degree over 40 years ago, and the research I did subsequently was not human biology or anything related so I am looking up everything just as much as everyone else! You had great answers from Dancinggirl and dahliagirl.
In terms of understanding what's going on in our bodies - I think I gave you the link to the article on this site about the biology of the peri-menopause and what happens to the hormones in our menstrual cycle? Now that you've read a lot more you may like to read it again as this is the clearest summary of what happens, without too much complicated biochemistry and terminology.
http://www.menopausematters.co.uk/article-perils-of-the-perimenopause.php The answer to your initial question is is that the biological process will just carry on even if you replace oestrogen through HRT ie HRT will not prevent the decline in ovarian function. However the added oestrogen will prevent the symptomns of oestrogen deficiency. This is why some women experience bleeding at odd times especially when taking HRT early in peri-menopause - because the cycle is doing its own thing. I can't explain how added oestrogen affects the cycling of pituitary hormones and the various hormone feedback mechanisms.
As for excess oestrogen - as CLKD said somewhere on the thread - progesterone normally balances oestrogen throughout your fertile years, because if it didn't, the uterus lining would over-thicken, could lead to endometrial hyperplasia and possibly cancer, and would shed erratically.
There was mention of progesterone in the body – yes it only exists at very high levels during the second half of the menstrual cycle – to prepare for pregnancy, and during pregnancy – which is its main function. However there is a very small amount of progesterone in men, in women during the first half of the menstrual cycle, and post-menopausally – so it is still there carrying out whatever function it does in the body aside from the major changes in pregnancy. That's why it is pointless testing for it.
In terms of oestrogen dominance – I think it's already been mentioned and also as above that oestrogen is dominant during the first half of the natural menstrual cycle – when women usually feel at their best once the period is over. As Dancinggirl says the concept is a distraction because it implies that if it is not “balanced†by progesterone there will be unpleasant symptoms until the balance is restored. The fact is - it is true that progesterone is needed to “balance†oestrogen – but only to protect the uterus lining. If this were not the case, as Dancinggirl points out, no-one who had had a hysterectomy and was on HRT would be able to function without feeling unwell. It is also not helpful because it doesn't take into account the symptoms and problems caused by absolute depletion of oestrogen per se.
Having said that – yes, due to anovulatory cycles additional progesterone may well be needed temporarily (as well as oestrogen), in order to thin the lining and prevent heavy bleeding. This protection cannot be provided by progesterone cream despite what some websites and advocates might suggest.
To keep this post relatively short - I'll comment on some of the other points separately
Hope my ramble is of some help - and doesn't repeat what others have said too much!
Hurdity x
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Topic: Can anyone give me a chemistry lesson? (Read 44570 times)