Endocrinology II Flashcards
What does the outer cortex of the adrenal gland produce?
Inner medulla?
Cortex - steroid hormones
Medulla - Catecholamines
What 3 classes of molecules are made in the Adrenal Cortex?
mineralocorticoids
glucocorticoids
androgens
What are the 3 steroid hormones of the Adrenal Cortex?
Aldosterone - (mineralocorticoid)
Cortisol - (glucocorticoid)
Dehydroepiandrosterone - (androgen)
What 2 hormones are made in the adrenal medulla?
Epinepherine
Norpepinepherine
*the catecholamines
Why are cortisol, aldosterone, and adrenal androgens bound to transport proteins in the blood?
otherwise would be excreted because of size
Describe the Cortisol feedback loop:
CRH > ACTH > Cortisol
What increases CRH pulses?
Illness, surgery, injury, psychiatric stress
any stress
How is ACTH released from the Ant. Pituitary?
Pulses
Rhythm (diurnal)
highest level 4-6 AM
What is the main immediate effect of Cortisol?
Increase blood glc
GNG, insulin resistance, glycogen storage, appetite
T/F
Cortisol suppresses inflammation, immune response, and wound healing.
Yes
T/F
Aldosterone is stimulated by ACTH
Yes, some
but mostly controlled by the kidney renin-angiotensin system
What are the effects of Aldosterone?
Holds Sodium
Pumps out Potassium
Maintains blood volume and pressure
Will ACTH stimulate all of the hormones of the adrenal cortex?
Yes
What is the function of DHEA?
masculinizing hormone
(pubic hair)
in excess causes hirsutism (male and female)
T/F
ACTH, cortisol, aldosterone, DHEA can all be found in the plasma and saliva for testing purposes?
True
What are some causes of primary adrenal insufficiency?
Autoimmune Infection (TB, cytomegalovirus in HIV) Cancer Hemorrhage Surgical removal
What would be low and what would be high in Primary Adrenal Insufficiency?
Glucocorticoid (Cortisol), Mineralocorticoid (Aldosterone), and Adrenal androgen (DHEA) lost/low
ACTH high
What might cause the following: fatigue weight loss, nausea abdominal pain low glc illness amplified
Low cortisol
What might cause the following:
low Na, high K
low BP
Low aldosterone
What causes hyperpigmentation?
high ACTH
*note - in patients see especially in mucous lining of the mouth
What does ACTH do at high concentrations?
stimulates melanocytes
What are the symptoms of acute adrenal crisis?
weakness nausea vomiting dehydration hypotension hypoglycemia
What cortical hormone of the kidney is functionally viable in secondary adrenal insufficiency?
Aldosterone
regulated mostly by kidneys
What is the treatment for both primary and secondary adrenal insufficiencies?
Cortisol and Cortisol
What syndrome is defined by an excess of Cortisol?
Cushing Syndrome
What causes Cushing disease?
*as opposed to Cushing Syndrome?
Pituitary tumor producing ACTH
What causes Cushing Syndrome?
anything that increases ACTH
adrenal tumor, prescribed glucocorticoids, etc.
What is a classic sign of Cortisol excess?
Cushing Syndrome
Purple stretch marks
Moon face
High glc production, insulin resistance, hyperglycemia, and diabetes can be caused by…
Cortisol Excess
What does Dexamethasone do?
Synthetic glucocorticoid so it suppresses ACTH
What 3 levels can you address too much ACTH secretion pharmacologically?
block ACTH secretion
inhibit cortisol production
block cortisol receptors
What is more important, the Adrenal medulla or cortex?
cortex
can survive without epi/norepi
What is the tumor of the Adrenal Medulla?
Pheochromocytoma
High ACTH, low cortisol, hyperpigmentation:
Adrenal insufficiency
either autoimmune or TB-related
treat with Cortisol
High ACTH, high cortisol, hirsutism, full face.
Cushings Disease
caused by tumor
What is the RDA for calcium 19-70?
1000 mg
What 2 things does Vitamin D increase absorption of from the gut?
Calcium and Phosphorous
What are the 2 sources of Vitamin D?
sunlight (cholecalciferol - D3)
plants (ergocalciferol - D2)
What type of Vitamin D is usually measured?
Storage form in Liver
Vitamin D is a ______ hormone that increases absorption of both ____ and ____.
Steroid
Calcium, Phosphorous
Name 4 Calcium regulating hormones.
PTH
PTHrP
Calcitonin
Vitamin D
T/F
PTH is a slow acting hormone
False
controls Calcium on timescale of around a minute
Why does PTH decrease Phosphorous?
Its actions in the kidney preserve Calcium and secrete phosphorous
What does PTH increase?
Calcium and Vitamin D
What is the difference between PTH and PTHrP?
PTHrP increases Calcium (like PTH) but does NOT activate Vitamin D.
net effect: increase Ca, decrease PO4, PTH
What can cause hypercalcemia?
Too much PTH, Vitamin D, or PTHrP
What can cause hypocalcemia?
Not enough PTH or Vitamin D
Resistance to PTH, Vitamin D
What are the major causes of hypercalcemia?
high PTH or PTHrP (tumor)
high Vitamin D
What are the symptoms of hypercalcemia?
high PTH or PTHrP (tumor)
high Vitamin D
What are the symptoms of Hypercalcemia?
Stones, groans, moans, overtones, bones
Primary Hyperparathyroidism:
Ca Phos 1,25D PTH
high, low, high, high
What are the causes of Hypocalcemia?
low PTH
low Vitamin D
low Calcium intake
What is the main symptom of Hypocalcemia?
neuromuscular irritability
What are low PTH effects on:
Ca Phos 1,25D
low, high, low
Low Ca, Phos, and high PTH
Unmineralized bone
diagnosis?
Rickets
Childhood Vitamin D deficiency
What does severe Vitamin D deficiency lead to in adults?
Osteomalacia
- diffuse bone pain
- everything low but PTH
What indicates Renal Failure?
low Ca, 1,25D
high Phos, PTH
What is the difference between Primary and Secondary Hyperparathyroidism?
Primary - failure at parathyroid (too much PTH causes high calcium)
Secondary - low vitamin D or kidney failure
*high PTH secondary to low calcium
RANK/RANKL are part of what system?
Immune
What is a major osteoclast inhibitory factor?
Osteoprotegerin
Is low weight a risk factor in bone fracture?
Yes - incidental to frailty
(somewhat counterintuituve)
Can Glucocorticoids cause fractures?
Yes
could’ve been designed as evil for bones
What are some preventions/treatments for osteoporosis?
Calcium and Vitamin D
Exercise
Osteoclast inhibition
Osteoblast stimulation
What are treatments that inhibit osteoclasts?
Denosumab (RANKL antibody)
Calcitonin
Bisphosphonates
Estrogen/SERMS
(also, Calcium supplements)
What does SERM stand for and what do they do?
Selective Estrogen Receptor Modulators
Act at Estrogen Receptors in bone but NOT in breast/uterus
*effective osteoclast suppressor
How do bisphosphonates work?
Bind Ca++ to bone
Increase osteocyte death
Long half life
What is a possible dental side effect of Bisphosphonates?
other side effects?
Jaw osteonecrosis
(probably due to high turnover)
Atypical femoral fractures
(uncommon)
What two treatments are associated with jaw osteonecrosis and atypical femur fractures?
Denosumab and Bisphosphonates
When can exercise increase bone density?
Only when very intense
- otherwise will stabilize bone density
What is a counter-intuitive treatment for bone loss?
hPTH (PTH analog)
- stimulates osteoclasts, but osteoblasts and osteocytes more.
- effective, expensive, and shown to cause horrible bone cancer when given in high doses to rats
