Abstract
The CYP11B2 enzyme is the terminal enzyme in the biosynthesis of aldosterone.
Immunohistochemistry using antibodies against CYP11B2 defines cells of the
adrenal ZG that synthesize aldosterone. CYP11B2 expression is normally
stimulated by angiotensin II, but becomes autonomous in primary
hyperaldosteronism, in most cases driven by recently discovered somatic
mutations of ion channels or pumps. Cells expressing CYP11B2 in young normal
humans form a continuous band beneath the adrenal capsule; in older individuals
they form discrete clusters, aldosterone-producing cell clusters (APCC),
surrounded by non-aldosterone producing cells in the outer layer of the adrenal
gland. Aldosterone-producing adenomas may exhibit a uniform or heterogeneous
expression of CYP11B2. APCC frequently persist in the adrenal with an
aldosterone-producing adenoma suggesting autonomous CYP11B2 expression in these
cells as well. This was confirmed by finding known mutations that drive
aldosterone production in adenomas in the APCC of clinically normal people.
Unilateral aldosteronism may also be due to multiple CYP11B2-expressing nodules
of various sizes or a continuous band of hyperplastic ZG cells expressing
CYP11B2. Use of CYP11B2 antibodies to identify areas for sequencing has greatly
facilitated the detection of aldosterone-driving mutations.
Key words
aldosterone - immunochemistry - aldosternism