Endocrine Function III (part 1) Flashcards
Basic anatomy of the adrenal cortex
(outer) capsule, adrenal cortex, adrenal medulla (inner)
Three layers of the adrenal cortex
- Zona Glomerulosa (outermost)
- Zona Fasciculata (middle layer)
- Zona Reticularis (innermost layer)
Three major hormone classes of the adrenal cortex
Estrane
Androsane
Pregnane
Major hormone(s) produced by Zona Glomerulosa layer
Mineralocorticoids
Major hormone(s) produced by Zona Faciculata layer
Glucocorticoids
Major hormone(s) produced by Zona Reticularis layer
Sex Hormones
Number of carbons on estrogens, androgens, and adrenal steroids
estrogens: 18
androgens: 19
adrenal steroids: 21
First Biosynthetic pathway for adrenocorticosteroid formation
Acetate to Cholesterol to Pregnenolone to Adrenocorticoids
Second Biosynthetic pathway for adrenocorticosteroid formation (not preferred)
Pregnenolone to DHEA to Androstenedione to Testosterone to (Estradiol)
Causes of adrenocorticosteroids utilizing alternate pathway instead of the preferred pathway
Enzyme deficiencies
Importance of enzymes in steroid biogensis
Takes enzymes to make conversions to final product
Major site of steroid metabolism
liver
Form of adrenocorticosteroids excreted in the urine
Liver is site of catabolism; water insoluble hormones must be conjugated with sulfates or glucuronic acid to be excreted in urine
Steroid which has a neg feedback effect on adrenocorticotrophic hormone
Cortisol
Name of the principle cortisol-binding protein
CBG
mineralocorticoids
- metabolic effects
maintain sodium and potassium balance
Most potent glucocorticoid
cortisol
Most potent mineralocorticoid
aldosterone
most potent adrenocortical androgen
Testosterone
Four specific regulatory factors for aldosterone (order in importance)
- Potassium secretion
- Renin-angiotensin-aldosterone system
- Total body sodium concentration
- ACTH
What is the role of renin-angiotensin system on the regulation of aldosterone
Know the system! Releases aldosterone and reabsorbs Na and releases K+
seven metabolic effects of glucocorticoids
- Promotion of gluconeogenesis and lipolysis
- Promotion of liver glycogenesis
- Promotion of liver glycogenolysis
- Inhibition of protein synthesis and promotion of protein catabolism
- Increased anti-inflammatory and immunosuppressive action
- Decreased intestinal absorption of calcium; increased loss of calcium from bone matrix
- Miscellaneous: enzyme production, appetite promotion; regulation of blood pressure
Three regulatory factors for the release of glucocorticoids
- ACTH stimulation of hormone
- Normal diurnal variation
- Stress
feedback mechanism utilized in glucocorticoid hormonal regulation
Cortisol causes negative feedback on hypothalamus and anterior pituitary
Normal diurnal variation of cortisol
While sleeping, cortisol is very low so negative feedback is removed; ACTH is released and there is a sharp increase while waking up (blood pressure and sugar increase so you don’t pass out). The cortisol levels decrease over the day. By 4pm it should be 1/3 the level it was at 8am.
What androgen is produced in the greatest quantity by the adrnal cortex
Testosterone
List six conditions associated with a hypo functioning adrenal cortex
- Primary hypoaldosteronism
- Secondary hypoaldosteronism
- Addison’s disease
- Acute adrenal insufficiency
- Secondary and tertiary adrenal insufficiency
Differentiate causes of primary hypoaldosteronism
Inability to adjust to stress, low NA, high K, high renin, low ALD
Differentiate causes of secondary hypoaldosteronism
Occurs in patient with renal disease, kidney unable to produce and release renin and therefore cause low ALD
List the typical sodium, potassium, and renin levels observed in hypoaldosteronism
Low Na, high K, high renin
