Disorders of steroid 11β-hydroxylase isozymes

Perrin C. White, Kathleen M. Curnow, Leigh Pascoe

Research output: Contribution to journalReview articlepeer-review

317 Scopus citations

Abstract

The most active corticosteroids are 11β-hydroxylated. Humans have two isozymes with 11β-hydroxylase activity that are respectively required for cortisol and aldosterone synthesis. CYP11B1 (11β-hydroxylase) is expressed at high levels and is regulated by ACTH, whereas CYP11B2 (aldosterone synthase) is normally expressed at low levels and is regulated by angiotensin II. In addition to 11β-hydroxylase activity, the latter enzyme has 18- hydroxylase and 18-oxidase activities and thus can synthesize aldosterone from deoxycorticosterone. Insights into the normal functioning of these enzymes are gained from studies of disorders involving them. Mutations in the CYP11B1 gene cause steroid 11β-hydroxylase deficiency, a form of congenital adrenal hyperplasia characterized by signs of androgen excess and by hypertension. Mutations in CYP11B2 result in aldosterone synthase (corticosterone methyloxidase) deficiency, an isolated defect in aldosterone biosynthesis that can cause hyponatremia, hyperkalemia, and hypovolemic shock in infancy and failure to thrive in childhood. These are both recessive disorders. Unequal crossing over between the CYP11B genes can generate a duplicated chimeric gene with the transcriptional regulatory region of CYP11B1 but sufficient coding sequences from CYP11B2 so that the encoded enzyme has aldosterone synthase (i.e. 18-oxidase) activity. This results in aldosterone biosynthesis being regulated by ACTH, a condition termed glucocorticoid-suppressible hyperaldosteronism. This form of genetic hypertension is inherited in an autosomal dominant manner.

Original languageEnglish (US)
Pages (from-to)421-438
Number of pages18
JournalEndocrine reviews
Volume15
Issue number4
DOIs
StatePublished - Aug 1994

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Endocrinology

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