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Receptor binding and biological activity of 18-hydroxycortisol
Endocrinology
|August 1, 1984
Summary
18-hydroxycortisol, found in primary aldosteronism patients, shows minimal glucocorticoid and undetectable mineralocorticoid activity. This suggests it does not contribute to metabolic syndrome despite excess production.
Area of Science:
- Endocrinology
- Steroid biochemistry
Background:
- 18-hydroxycortisol was recently identified in patients with primary aldosteronism.
- Its potential role in metabolic syndrome requires investigation due to its structural similarity to active corticosteroids.
Purpose of the Study:
- To investigate the receptor-binding activity and biological functions of synthetic 18-hydroxycortisol.
- To determine if 18-hydroxycortisol possesses significant glucocorticoid or mineralocorticoid activity.
Main Methods:
- Assessed competitive binding to renal mineralocorticoid and glucocorticoid receptors using radioligand assays.
- Evaluated in vitro glucocorticoid activity via tyrosine aminotransferase induction in HTC cells and L929 fibroblast growth inhibition.
Main Results:
- 18-hydroxycortisol exhibited low binding affinity for both mineralocorticoid (0.13% of aldosterone) and glucocorticoid receptors (0.1% of dexamethasone).
- Glucocorticoid activity was detectable but too low for quantification in cell-based assays.
- Mineralocorticoid activity was undetectable.
Conclusions:
- 18-hydroxycortisol demonstrates minimal glucocorticoid and no significant mineralocorticoid activity.
- It is unlikely to play a role in the metabolic syndrome of patients with primary aldosteronism who overproduce this steroid.