Related Experiment Videos
Regulation of oestrogen action: role of 17 beta-hydroxysteroid dehydrogenases
M Poutanen1, V Isomaa, H Peltoketo
1Department of Clinical Chemistry, University of Oulu, Finland.
Abstract:
The target cell responses to steroid hormones, such as oestrogens, are dependent on the expression of their receptors. Apart from receptor concentration, another key regulatory factor in steroid hormone action is the intracellular hormone concentration, which is affected by three main variables: the concentration of the steroid in plasma, local production and local conversion into metabolites. During the reproductive years the main source of oestrogens is the ovarian follicle, but in postmenopausal women most of the oestrogens are formed in peripheral tissues. The present overview deals with the formation of active oestrogens in steroidogenic tissues and in oestrogen target tissues, and the main focus is on 17 beta-hydroxysteroid dehydrogenases, which catalyse the interconversion between oestradiol and oestrone. It is evident that different 17 beta-hydroxysteroid dehydrogenase isoenzymes are responsible for the oxidation/reduction of oestradiol or oestrone in oestrogen target cells. Because these enzymes are involved in the biosynthesis and metabolism of oestrogens, they have an important physiological significance for the growth of oestrogen-dependent tissues and, hence, the growth and progression of hormone-dependent tumours.
Insights
Oestrogen action depends on receptor expression and intracellular hormone levels. 17 beta-hydroxysteroid dehydrogenases (17β-HSDs) are key enzymes regulating oestrogen metabolism in target tissues, influencing hormone-dependent tumour growth.
Area of Science:
- Endocrinology
- Molecular Biology
- Biochemistry
Background:
- Cellular response to steroid hormones like oestrogens relies on receptor expression.
- Intracellular hormone concentration, influenced by plasma levels, local production, and metabolism, is crucial for hormone action.
- Oestrogen sources shift from ovarian follicles in reproductive years to peripheral tissues postmenopause.
Purpose of the Study:
- To review the formation of active oestrogens in steroidogenic and target tissues.
- To highlight the role of 17 beta-hydroxysteroid dehydrogenases (17β-HSDs) in oestrogen interconversion.
- To discuss the physiological significance of 17β-HSDs in oestrogen metabolism and hormone-dependent tumour progression.
Main Methods:
- Literature review focusing on oestrogen biosynthesis and metabolism.
- Analysis of the role of 17 beta-hydroxysteroid dehydrogenases (17β-HSDs) in oestrogen target cells.
- Discussion of isoenzyme-specific functions in oestradiol/oestrone interconversion.
Main Results:
- Different 17 beta-hydroxysteroid dehydrogenase (17β-HSD) isoenzymes mediate oestradiol and oestrone oxidation/reduction in target cells.
- These enzymes are critical for regulating intracellular active oestrogen concentrations.
- The activity of 17β-HSDs impacts oestrogen-dependent tissue growth.
Conclusions:
- 17 beta-hydroxysteroid dehydrogenases (17β-HSDs) play a vital role in oestrogen homeostasis within target tissues.
- Understanding 17β-HSD isoenzyme function is significant for comprehending oestrogen-dependent tissue development.
- Targeting 17β-HSDs may offer therapeutic strategies for hormone-dependent cancers.