oestrogens
Table of Contents
oestrogens
introduction
- mainly beta-oestradiol, but also oestrone & oestriol, the latter being the almost totally impotent liver metabolite of the former two.
- oestrogenic potencies:
- oestradiol 12 x oestrone & 80 x oestriol;
- oestradiol mainly secreted from ovary & placenta;
- oestrone secreted in small amounts from ovary but also formed by peripheral tissue conversion of androgens secreted from adrenal cortices;
- cellular effect:
- enter cells, bind to i/cell. receptor, migrate to nucleus, interact with DNA
- ⇒ alter transcription & increased DNA ⇒ mitosis;
- a specific anabolic action targeted to certain organs rather than non-specific testosterone anabolic activity;
actions:
pubertal enlargement & changes of female sexual organs:
- vaginal epithelium from cuboidal ⇒ stratified;
- pubic hair growth (but mainly via androgens);
- breast development:
- stromal tissues increased;
- extensive ductile system;
- deposition fat increased;
- endometrial proliferation;
Fallopian tube
- glandular proliferation, enhanced cilia;
bones
- increased osteoblastic activity ⇒ pubertal growth surge
- ⇒ earlier epiphyseal closure than testostestone
- ⇒ decreased osteoporosis as:
- increased bone matrix;
- increased deposition of bone Ca & P;
other actions
- Slight increased protein deposition « as for testosterone;
- Slight increased BMR about 1/3rd as much as testosterone increase;
- increased fat deposition esp. breasts, s/c tissues, buttocks, thighs;
- Soft, smooth, thicker, more vascular skin;
- Slight Na & water retention as adrenocortical effect & only significant in pregnancy?
exogenous oestrogens
phytoestrogens
- plant derived substances with oestrogenic properties as well as other pharmacologic properties
- most phytoestrogens bind ERβ more readily than ERα
- 4 main groups:
- isoflavonoids: genistein, daidzein, coumestrol and equol
- flavonoids: 8-prenylnaringenin, 6“-acetylapiin
- stilbenes: resveratrol (grape skin, red wine)
- lignans
- sources:
- soy beans (genistein, daidzein)
- parsley (6”-acetylapiin, petroside)
- nuts, oilseeds, cereals, breads
- legumes
- see wikipedia
oestrogens.txt · Last modified: 2016/07/15 13:38 by 127.0.0.1