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36 Cards in this Set
- Front
- Back
What is the first step in production of adrenal steroids?
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Conversion of Cholesterol → Pregnenolone via Cholesterol Desmolase
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How do you produce Aldosterone?
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1. Cholesterol → Pregnenolone (Cholesterol Desmolase)
2. Pregnenolone → Progesterone (3β-hydroxysteroid dehydrogenase) 3. Progesterone → 11-deoxycorticosterone (21-hydroxylase) 4. 11-deoxycorticosterone → Corticosterone (11β-hydroxylase) 5. Corticosterone → Aldosterone (Aldosterone Synthase) |
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What are the molecules on the way from Cholesterol to Aldosterone?
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1. Cholesterol
2. Pregnenolone 3. Progesterone 4. 11-deoxycorticosterone 5. Corticosterone 6. Aldosterone |
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What are the enzymes on the way from Cholesterol to Aldosterone?
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1. Cholesterol Desmolase
2. 3β-hydroxysteroid dehydrogenase 3. 21-hydroxylase 4. 11β-hydroxylase 5. Aldosterone Synthase |
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How do you produce Cortisol?
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1. Cholesterol → Pregnenolone (Cholesterol Desmolase)
2. Pregnenolone → 17-hydroxypregnenolone (17α-hydroxylase) 3. 17-hydroxypregnenolone → 17-hydroxyprogesterone (3β-hydroxysteroid dehydrogenase) 4. 17-hydroxyprogesterone → 11-deoxycortisol (21-hydroxylase) 5. 11-deoxycortisol → Cortisol (11β-hydroxylase) Steps 2 and 3 can be switched around, but need both enzymes |
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What are the molecules on the way from Cholesterol to Cortisol?
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1. Cholesterol
2. Pregnenolone 3. 17-hydroxypregnenolone 4. 17-hydroxyprogesterone 5. 11-deoxycortisol 6. Cortisol OR 3. Progesterone (depending on order of enzymes) |
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What are the enzymes on the way from Cholesterol to Aldosterone?
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1. Cholesterol desmolase
2. 17α-hydroxylase 3. 3β-hydroxysteroid dehydrogenase 4. 21-hydroxylase 5. 11β-hydroxylase (Enzymes 2 and 3 can be done in either order) |
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How do you produce Estradiol?
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1. Cholesterol → Pregnenolone (Cholesterol Desmolase)
2. Pregnenolone → 17-hydroxypregnenolone (17α-hydroxylase) 3. 17-hydroxypregnenolone → Dehydroepiandrosterone (DHEA) 4. DHEA → Androstenedione 5. Androstenedione → Estrone (Aromatase) 6. Estrone → Estradiol OR 5. Androstenedione → Testosterone 6. Testosterone → Estradiol (Aromatase) |
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What are the actions of Aromatase?
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- Androstenedione → Estrone
- Testosterone → Estradiol |
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What are the actions of 5α-Reductase?
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Testosterone → Dihydrotestosterone (DHT)
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Which enzyme deficiency would cause:
- Mineralocorticoids: ↑ - Cortisol: ↓ - Sex Hormones: ↓ |
17α-Hydroxylase (A)
Glucocorticoid and Androgen/Estrogen precursors cannot be produced, which shuttles more Pregnenolone / Progesterone substrate through the Aldosterone pathway |
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Which enzyme deficiency would cause:
- Mineralocorticoids: ↓ - Cortisol: ↓ - Sex Hormones: ↑ |
21-Hydroxylase (B)
Progesterone and 17-Hydroxyprogesterone cannot continue towards formation of Aldosterone and Cortisol, so they get shuttled to the sex hormone pathway |
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Which enzyme deficiency would cause:
- Mineralocorticoids: ↓ / ↑ - Cortisol: ↓ - Sex Hormones: ↑ |
11β-Hydroxylase (C)
- ↓ Aldosterone - ↑ 11-deoxycorticosterone (results in ↑ BP) - Cortisol can't be made - Sex hormones increased due to extra substrate |
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What is similar about 17α-hydroxylase, 21-hydroxylase, and 11β-hydroxylase deficiencies?
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All congenital adrenal enzyme deficiencies → enlargement of both adrenal glands due to ↑ ACTH stimulation (due to ↓ cortisol)
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What labs are associated with 17α-hydroxylase deficiency?
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- ↑ Mineralocorticoids
- ↓ Cortisol - ↓ Sex hormones (↓ DHT) - Hypertension - Hypokalemia |
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How does a patient with 17α-hydroxylase deficiency present?
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↑ Mineralocorticoids, ↓ Cortisol, and ↓ Sex hormones causes:
- XY: pseudo-hermaphroditism (ambiguous genitalia, undescended testes) - XX: lack secondary sexual development - Both: hypertension, hypokalemia |
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What labs are associated with 21-hydroxylase deficiency?
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- ↓ Mineralocorticoids
- ↓ Cortisol - ↑ Sex hormones (↑ 17-hydroxy-progesterone) - Hypotension - Hyperkalemia - ↑ Renin activity |
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How does a patient with 21-hydroxylase deficiency present?
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↓ Mineralocorticoids, ↓ Cortisol, and ↑ Sex Hormones causes:
- Presents in infancy with salt-wasting or in childhood with precocious puberty - XX: virilization - Hypotension, hyperkalemia, ↑ Renin activity |
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What labs are associated with 11β-hydroxylase deficiency?
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- ↓ Aldosterone
- ↑ 11-deoxycorticosterone (results in ↑ BP) - Hypertension - Low renin - ↓ Cortisol - ↑ Sex hormones |
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How does a patient with 11β-hydroxylase deficiency present?
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↓ Aldosterone, ↑ 11-deoxycorticosterone, ↓ Cortisol, and ↑ Sex hormones causes:
- XX: virilization - Hypertension |
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What diagnosis should you consider in an XY patient who presents with pseudo-hermaphroditism (ambiguous genitalia, undescended testes)? Other findings?
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17α-hydroxylase deficiency
- Hypertension - Hypokalemia - ↓ Sex hormones (↓ DHT) - ↓ Cortisol - ↑ Aldosterone |
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What diagnosis should you consider in an XX patient lacking secondary sexual development? Other findings?
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17α-hydroxylase deficiency
- Hypertension - Hypokalemia - ↓ Sex hormones (↓ DHT) - ↓ Cortisol - ↑ Aldosterone |
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What diagnosis should you consider in an infant presenting with salt wasting? Other findings?
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21-Hydroxylase deficiency
- Hypotension - Hyperkalemia - ↓ Mineralocorticoids - ↓ Cortisol - ↑ Sex hormones |
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What diagnosis should you consider in an child with precocious puberty? Other findings?
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21-Hydroxylase deficiency
- Hypotension - Hyperkalemia - ↓ Mineralocorticoids - ↓ Cortisol - ↑ Sex hormones |
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What diagnosis should you consider in an XX patient with virilization? Other findings?
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21-Hydroxylase deficiency
- Hypotension - Hyperkalemia - ↓ Mineralocorticoids - ↓ Cortisol - ↑ Sex hormones OR 11β-Hydroxylase deficiency - Hypertension (d/t ↑ 11-deoxycorticosterone) - ↓ Aldosterone - ↓ Cortisol |
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What is the source of Cortisol? What does it bind in the blood?
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- Adrenal Zona Fasciculata
- Binds to corticosteroid-binding globulin |
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What are the effects of Cortisol?
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Cortisol is a BIG FIB:
- ↑ BP - ↑ Insulin resistance - ↑ Gluconeogenesis, lipolysis, and proteolysis - ↓ Fibroblast activity - ↓ Inflammatory and immune responses - ↓ Bone formation |
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How does cortisol affect BP?
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↑ BP: upregulates α1-receptors on arterioles → ↑ sensitivity to NE and Epi
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How does cortisol affect insulin?
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↑ Insulin resistance → diabetogenic
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How does cortisol affect stored forms of energy?
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- ↑ Gluconeogenesis
- ↑ Lipolysis - ↑ Proteolysis |
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How does cortisol affect fibroblasts? Effect?
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↓ Fibroblast activity → causes striae
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How does cortisol affect inflammation / immune responses?
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↓ Inflammatory and Immune responses:
- Inhibits production of leukotrienes and prostaglandins - Inhibits leukocyte adhesion → neutrophilia - Blocks histamine release from mast cells - Reduces eosinophils - Blocks IL-2 production |
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How does cortisol affect bones?
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↓ Bone formation due to ↓ Osteoblast activity
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What infections can be reactivated after administration of exogenous corticosteroids? How?
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Reactivation of TB and Candidiasis
- Due to blocked IL-2 production |
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How is Cortisol regulated?
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- CRH (hypothalamus) stimulates ACTH release (pituitary), causing cortisol production in adrenal zona fasciculata
- Excess cortisol ↓ CRH, ACTH, and cortisol secretion |
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What is the effect of chronic stress on cortisol?
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Chronic stress induces prolonged secretion of Cortisol
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