types
Last edited 05/2020
There are three main endogenous oestrogens:
- oestrone (estrone E1)
- formed from oestradiol in a reversible reaction
- predominant form of circulating estrogen after menopause
- oestrone is also a product of the peripheral conversion of androstenedione secreted by the adrenal cortex
- oestradiol-17beta (estradiol E2)
- primarily produced by theca and granulosa cells of the ovary
- predominant form of oestrogen found in premenopausal women
- oestriol (estriol E3)
- oestrogen the placenta secretes during pregnancy
- also is the peripheral metabolite of oestradiol and oestrone
- is not secreted by the ovary
Oestradiol is the most potent oestrogen; it has double the efficacy of oestrone and ten times the efficacy of oestriol. It is in equilibrium with the more concentrated oestrone. Oestrone is in equilibrium with its sulphated form.
Synthetic oestrogens include:
- ethinyloestradiol
- oestradiol valerate
- mestranol
- stilboestrol