Adrenal enzyme deficiencies, specifically congenital adrenal hyperplasia (CAH), and their corresponding effects are frequently tested in board exams (USMLE and ABIM). This is a simple mnemonic for remembering all the critical steps in the adrenal steroid hormone synthesis pathway. I have used this approach to simplify this daunting pathway for medical students and endocrinology fellows.
The CAH mnemonic
- Remember that all adrenal steroids are synthesized from cholesterol (The StAR of the show).
- Start with this memory aid — Pregnancy requires Progesterone before the DOCtor delivers ALDOsterone in 3, 2, 1… Write all of the critical steroids and hydroxylases (enzymes) required for mineralocorticoid synthesis in the left column.
The first part of this memory aid refers to the major steroids in the first layer of the adrenal cortex (zona glomerulosa) required for mineralocorticoid synthesis.
Pregnancy = Pregnenolone
↓
Progesterone = Progesterone
↓
DOC = 11-deoxycorticosterone (11-DOC)
↓
ALDO = Aldosterone
3 = 3-Beta hydroxysteroid dehydrogenase (between Pregnenolone and Progesterone)
2 = 21 hydroxylase (between progesterone and 11-DOC)
1 = 11-Beta hydroxylase between 11-DOC and Aldosterone)
- The second layer of the adrenal cortex i.e., zona fasciculata, is responsible for the formation of 17 hydroxy steroids. Just change Pregnenolone to 17 hydroxypregnenolone, Progesterone to 17 hydroxyprogesterone, and 11-DOC to 11-Deoxycortisol to arrive at the sequential intermediate steroids required to form cortisol.
- The same set of hydroxylases will convert these steroids sequentially in the zona fasciculata.
- 3 = 3-Beta hydroxysteroid dehydrogenase (between 17 hydroxy Pregnenolone and 17 hydroxy Progesterone)
- 2 = 21 hydroxylase (between 17 hydroxy Progesterone and 11-Deoxycortisol)
- 1 = 11-Beta hydroxylase (between 11-Deoxycortisol and Cortisol)
The third and final layer of the adrenal cortex, i.e., zona reticularis, is responsible for the formation of 17 ketosteroids. These are the sex steroids. A simple memory aid is that “SEX may occur after a DATE“. DATE refers to the sequential steroids in this final pathway…D (Dehydroepiandrosterone), A (Androstenedione), T (Testosterone), and E (Estradiol)
References
Anita H. Payne, Dale B. Hales, Overview of Steroidogenic Enzymes in the Pathway from Cholesterol to Active Steroid Hormones, Endocrine Reviews, Volume 25, Issue 6, 1 December 2004, Pages 947–970
Images(s) Courtesy
MyEndoConsult
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