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Apparent mineralocorticoid excess syndromes
1Department of Medicine, University of Birmingham, Queen Elizabeth Hospital, Edgbaston, England.
Journal of Endocrinological Investigation
|July 1, 1995
Summary
Apparent mineralocorticoid excess (AME) results from impaired 11 beta-dehydrogenase (11 beta-OHSD) activity, leading to hypertension and hypokalemia. A newly identified 11 beta-OHSD 2 isoform may explain AME pathogenesis.
Area of Science:
- Endocrinology
- Genetics
- Metabolic Disorders
Background:
- Apparent mineralocorticoid excess (AME) is characterized by hypertension and hypokalemia due to cortisol's mineralocorticoid activity.
- This occurs when 11 beta-dehydrogenase (11 beta-OHSD) activity is deficient, impairing cortisol inactivation.
Purpose of the Study:
- To investigate the role of 11 beta-dehydrogenase (11 beta-OHSD) in apparent mineralocorticoid excess (AME).
- To identify the specific isoform responsible for the AME phenotype.
Main Methods:
- Analysis of urinary cortisol/cortisone metabolite ratios.
- Assessment of cortisol half-life.
- Isolation and characterization of human 11 beta-OHSD 2 cDNA.
Main Results:
- Elevated urinary cortisol/cortisone metabolites and prolonged cortisol half-life are diagnostic indicators.
- Acquired inhibition of 11 beta-DH by glycyrrhetinic acid (from licorice) mimics AME.
- A second 11 beta-OHSD isoform (11 beta-OHSD 2) has been identified.
Conclusions:
- 11 beta-OHSD 2 appears to confer specificity to renal mineralocorticoid receptors.
- Defects in 11 beta-OHSD 2 activity are strongly implicated in the pathogenesis of apparent mineralocorticoid excess (AME).