12 Questions
What is the primary cause of decreased synthesis of adrenocorticoid hormones due to an enzyme defect?
Reduced glucocorticoid synthesis leading to disinhibition of corticoliberins and corticotropin
What is the purpose of using ACTH to stimulate adrenocorticoid hormone production in the case of an enzyme defect?
To normalize glucocorticoid production despite the enzyme defect
What is the potential effect of an excess of gestagenic metabolites in the case of an enzyme defect?
Increased natriuresis due to the weak antimineralocorticoid effect
What is the primary enzyme defect that can lead to decreased synthesis of adrenocorticoid hormones?
Deficiency in steroidogenic acute regulatory protein (StAR)
What is the effect of an enzyme defect on the synthesis of adrenocorticoid hormones?
Decreased synthesis of enzyme products and hormones
What is the potential effect of the increased concentration of enzyme substrates, precursors, and metabolites in the case of an enzyme defect?
Increased or decreased hormonal effects depending on the activity of those products, substrates, precursors, and metabolites
Which of the following statements is incorrect regarding the adrenal cortical hormones?
Their secretion is controlled solely by ACTH from the anterior pituitary gland.
Which of the following is true regarding the binding of adrenal cortical hormones to plasma proteins?
The binding of hormones to plasma proteins may extend their duration of action.
Which of the following is the primary site for the metabolism of adrenal cortical hormones?
Liver
What is the final step in the metabolism of adrenal cortical hormones before their elimination?
They are conjugated and made water-soluble.
Which of the following statements is true regarding the elimination of adrenal cortical hormones?
They are eliminated in both urine and bile.
How many different types of adrenal cortical hormones are mentioned in the text?
4
Study Notes
Enzyme Defects in Adrenocortical Hormone Formation
- Deficiency in steroidogenic acute regulatory protein (StAR) impairs cholesterol transport to mitochondria and pregnenolone transformation.
- Enzyme defects lead to decreased synthesis of hormones and their products.
- Reduced glucocorticoid synthesis leads to increased corticoliberin (CRH) and corticotropin (ACTH) formation, stimulating adrenal cortex growth and cholesterol release.
Consequences of Enzyme Defects
- Rise in concentration of enzyme substrates, precursors, and metabolites, as well as active steroids preceding the enzyme defect.
- These steroids have hormonal effects: glucocorticoid, mineralocorticoid, androgenic, progestogenic, and estrogenic.
Adrenal Cortical Hormones
- Over 30 hormones are produced by the adrenal cortex.
- Main adrenocortical hormones: glucocorticoids and mineralocorticoids.
- Androgens, progestogens, and estrogens are also formed in the adrenal cortex.
- All adrenal cortical hormones are steroids synthesized from acetate and cholesterol.
- Each synthesis step requires a specific enzyme.
Regulation and Secretion
- ACTH from the anterior pituitary gland controls secretion of glucocorticoids and adrenal androgens.
- Cortisol, aldosterone, and adrenal androgens are secreted in an unbound state and bind to plasma proteins for transport.
- Cortisol binds to corticosteroid-binding globulin and albumin, while aldosterone and androgens circulate mainly bound to albumin.
Metabolism and Elimination
- Liver is the main site for metabolism of adrenal cortical hormones, where they undergo conversions before being conjugated and made water-soluble.
- Metabolites are eliminated in either the urine or bile.
Test your knowledge on the synthesis of adrenal cortical hormones, including glucocorticoids, mineralocorticoids, and sex hormones. Learn about the structures and synthesis pathways of these important hormones produced by the adrenal cortex.
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