1. Adrenal Steroid Hormone Synthesis & Congenital Adrenal Hyperplasias
High-Yield Review for Step 1
Tim Boswell
Created: 3/11/15

4. 17-hydroxypregnenolone dehydroepiandrosterone
cholesterol
cholesterol desmolase
17α-hydroxylase
pregnenolone
17-hydroxypregnenolone
dehydroepiandrosterone
3β-hydroxysteroid dehydrogenase
3β-hydroxysteroid dehydrogenase
3β-hydroxysteroid dehydrogenase
17α-hydroxylase
progesterone
17-hydroxyprogesterone
androstenedione
21β-hydroxylase
21β-hydroxylase
11-deoxycorticosterone
deoxycortisol
testosterone
11β-hydroxylase
11β-hydroxylase
corticosterone
cortisol
aldosterone synthase
aldosterone

5. Recap: Key points
Memory aid: GFR + “The deeper you go, the sweeter it gets”
Glomerulosa Aldosterone Salt
Fasciculata Cortisol Sugar
Reticularis Testosterone Sex
What are the primary actions of aldosterone?
retain Na+ -> elevated BP
excrete K+
excrete H+
Which intermediate has mineralocorticoid activity?
11-deoxycorticosterone (11-DOC)
ACTH -> increased activity of cholesterol desmolase
AT-II -> increased activity of aldosterone synthase

6. Congenital Adrenal Hyperplasias
Caused by deficiencies of certain enzymes in the adrenal steroid synthesis pathway
Low cortisol levels fail to perform feedback inhibition on the anterior pituitary -> excessive ACTH
ACTH activates the rate-limiting and integral first step of the entire steroid synthesis pathway, ramping up the adrenal steroid synthesis pathway
Intermediates are shunted into the intact branches of the pathway, excess steroid products accumulate
This ACTH stimulation induces hyperplasia of the adrenal cortex which causes the adrenal gland to be enlarged (detectable on imaging)
Presentations are logical with signs/symptoms following from deficiency and/or excess of steroid hormones. Main features are:
Abnormalities in sexual differentiation (virilization, precocious puberty, etc.)
Abnormalities in blood pressure and potassium level
Age of presentation (usually present early in life) and specific presenting features depend on severity of deficiency and gender

7. 17α-hydroxylase deficiency

8. 21β-hydroxylase deficiency

9. 11β-hydroxylase deficiency

10. Congenital Adrenal Hyperplasias
Enzyme Deficiency
Hormone Levels
Vitals/Labs/Clinical Presentation
17α-hydroxylase
Aldosterone
Cortisol
Testosterone
21β-hydroxylase
11β-hydroxylase

11. Recap: Important points
Hypertension + hypokalemia = possible hyperaldosteronism
normal potassium range =
21β-hydroxylase deficiency is the most common cause of CAH
Sexual differentiation: external genitalia are female by default (without influence of significant androgens)
Recommendation: memorize framework

12. THE END