21 - Adrenal Hormones Flashcards
The part of the adrenal gland secretes epinephrine and norepinephrine. It is functionally related to the sympathetic nervous system.
Medulla
This part of the adrenal gland secretes corticosteroids, such as mineralocorticoids, glucocorticoids, and androgenic hormones.
Cortex
Corticosteroids are synthesized from ________ provided mostly by LDLs in the plasma.
Cholesterol
Most cholesterol used to synthesize corticosteroids are attached to coated pits. ACTH increases the number of LDL receptors. Cholesterol is converted to ________ in the mitochondria, and the enzyme for conversion is cholesterol desmolase (rate-limiting step).
Pregnenolone
Both ______ and ______ increase the conversion of cholesterol to pregnenolone.
ACTH
Angiotensin II
Corticosteroids are 21-carbon steroids. What are all the corticosteroids?
Progesterone
Deoxycorticosterone
Aldosterone
Cortisol
If progesterone undergoes a hydroxylation at C-21, what corticosteroid is formed?
Deoxycorticosterone (mineralocorticoid)
Deoxycorticosterone can form what other corticosteroid?
Aldosterone
If progesterone undergoes a hydroxylation at C-17, what corticosteroid is formed?
Cortisol (glucocorticoid)
This is the major mineralocorticoid and its half-life is about 20 minutes.
Aldosterone
Aldosterone increases ________ reabsorption by kidney tubules. It acts on ________ cells in the late distal tubule.
Sodium
Principal
Hyperkalemia (INCREASES/DECREASES) aldosterone secretion.
Increases
Aldosterone increases ________ secretion by kidneys. Acts on _______ cells in the late distal tubule.
Potassium
Principal
Aldosterone increases ________ ion secretion by kidneys. Acts on intercalated cells in the late distal tubule.
Hydrogen
The secretion of aldosterone is controlled mainly by ________ and ________.
Angiotensin II
K+
Aldosterone is secreted by…
Zona glomerulosa
T/F. Aldosterone is responsible for restoring a decreased blood volume to normal.
True
______ and Angiotensinogen leads to secretion of Angiotensin I. Then, Angiotensin I and ACE leads to secretion of Angiotensin II. Angiotensin II is what makes Corticosterone into ________.
Renin
Aldosterone
***See Lecture 21 Slide 9
This is the major glucocorticoid and is essential in stress responses.
Cortisol
Cortisol secretions are controlled mainly by ______ (from anterior pituitary).
ACTH
ACTH up-regulates its own receptor and is under the influence of _______. Secondary messenger for both ______ and ACTH is cAMP.
CRH
CRH
Cortisol is secreted by the…
Zona fasciculata
Cortisol has (POSITIVE/NEGATIVE) feedback response to both CRH and ACTH.
Negative
Cortisol oscillates with circadian rhythm. It is normally (HIGHEST/LOWEST) before waking and (HIGHEST/LOWEST) in evening.
Highest
Lowest
These are 19-carbon steroids that have androgenic activity and are precursors to the estrogens.
Androgenic hormones
Androgenic hormones include…
DHEA
Androstenedione
DHEA is converted to ________ in the testes.
Testosterone
Adrenal androgens are excreted as 17-ketosteroids in the _______.
Urine
18-carbon steroids have ________ activity. Oxidation of one of the rings occurs in the ovaries to produce ________, but not in the adrenal glands or testes.
Estrogenic
Estrogen
Androgenic hormones are secreted by…
Zona reticularis
The loss of ________ causes death in a matter of days unless extensive salt therapy and mineralocorticoid injections are available.
Aldosterone
Without mineralocorticoids _______ levels in ECF rise markedly and _______ and ______ are lost rapidly from the urine.
Potassium
Sodium
Chloride
Without aldosterone, total ECF and blood volume become greatly…
Reduced
Without ________, a person develops diminished cardiac output and progresses to a shock-like state. Hyperkalemia and serous cardiac toxicity occur.
Aldosterone
When there is an excess of ________, there is an increase in ECF and arterial pressure. Hypokalemia, muscle weakness, and alkalosis occur.
Aldosterone
T/F. Excess aldosterone causes a large effect on plasma sodium concentration.
False. There is a small effect on plasma sodium concentration because sodium reabsorption in renal tubules is accompanied by equivalent amount of water reabsorption.
Excess aldosterone stimulates the transport of _______ from ECF into most cells of the body.
Potassium
Aldosterone increases renal tubular reabsorption of _______ and increases ________ in the urine.
Sodium
Potassium
Put the following cellular sequence of events leading to sodium reabsorption in order from first to last:
A. Sodium-Potassium ATPase pump proteins are among those formed as a result of this induction.
B. Aldosterone combines with mineralocorticoid receptor proteins.
C. RNA transcription is induced.
D. Aldosterone is lipid soluble and diffuses readily into the interior of the tubular epithelial cells.
E. Aldosterone-receptor complex diffuses into nucleus.
F. Epithelial sodium channel (ENaC) is also formed.
- D
- B
- E
- C
- A
- F
Regulation of aldosterone secretion is almost entirely independent of the regulation of ________ secretion.
Cortisol
Increased ________ ion concentration greatly increases aldosterone secretion.
Potassium
Increased ________ concentration greatly increases aldosterone secretion.
Angiotensin II
ACTH is necessary for aldosterone secretion but has little effect in controlling ______ of secretion.
Rate
Glucocorticoids stimulate _________ and may lead to “adrenal diabetes”.
Gluconeogenesis
What type of corticosteroid group has the following functions –
- Increases protein catabolism
- Mobilizes amino acids from extrahepatic tissues
- Enhances transport of amino acids into hepatic cells
- Increases enzymes required to convert amino acids to glucose
- Decreases glucose utilization by cells
- Increases lipolysis
Glucocorticoids
What type of corticosteroid group has the following functions –
- Resists stress
- Resists inflammation
- Causes resolution of inflammation
- Inhibits immune response
- Maintains vascular response to catecholamines
Glucocorticoids
Hypoadrenalism, or _______ disease is primarily due to injury to the adrenal cortex. It can secondarily be due to impaired function of the pituitary gland.
Addison’s
Addison’s disease disturbances are due to ________ deficiency, ________ deficiency, and melanin pigmentation.
Mineralocorticoid
Glucocorticoid
Addison’s disease disturbance due to _________ deficiency has the following symptoms:
- Decreased ECF volume
- Hyponatremia
- Hyperkalemia
- Mild acidosis
- Rise in RBC concentration
- Decrease in cardiac output
- Decrease in blood pressure
- Metabolic acidosis
- Death from shock
Mineralocorticoid
Addison’s disease disturbance due to _________ deficiency has the following symptoms:
- Loss of ability to maintain normal blood glucose concentrations between meals – hypoglycemia
- Reduction in both proteins and fats leading to depression of other bodily functions
- Weight loss, nausea, vomiting
- Muscle weakness
- Highly susceptible to stress
Glucocorticoid
Addison’s disease disturbance due to _______ _______ has the following symptoms:
– May be caused by loss of negative feedback to pituitary, allowing increased amounts of MSH
– Results in uneven distribution of pigmentation, especially in thin skin areas
Melanin pigmentation
Hyperadrenalism, or _______ disease, has the following causes:
- Administration of glucocorticoids
- Adenomas of anterior pituitary
- Abnormal function of hypothalamus
- Ectopic secretion of ACTH by tumor
- Adenomas of adrenal cortex
- Excess ACTH secretion is cause of disease
Cushing’s
This disease has the following characteristics:
- Increase in cortisol and androgen levels
- “Buffalo torso”
- Moon face
- Acne and hirsutism
- Hypertension
- Increased blood glucose
- Increase in protein catabolism and muscle wasting
Cushing’s disease
