Calcium Homeostasis (Welch) Flashcards
What is a SERM?
Selective Estrogen Receptor Modulation
What are 3 common SERMs?
- Tamoxifen
- Raloxifene
- Clomiphene
Tamoxifen, Raloxifene, and Clomiphene exert their effects how?
Competetive partial agonist inhibitor of estradiol at the estrogen receptor
What are 2 indications for Tamoxifen (a SERM)?
“Palliative treatment of breast cancer in post menopausal women”
“Chemoprevention of breast cancer in high risk women”
Of the SERMs Tamoxifen, Raloxifene, and Clomiphene, which ones increase bone density?
- Tamoxifene
2. Raloxifene
Of the SERMs Tamoxifen, Raloxifene , and Clomiphene, which ones increase ovulation?
- Clomiphene
2. Tamoxifene
Of the SERMs Tamoxifen, Raloxifene , and Clomiphene, which ones have an effect on mammary cell proliferation?
None
Of the SERMs Tamoxifen, Raloxifene , and Clomiphene, which ones increase uterine cell proliferation?
Tamoxifene
What is the only thing that Raloxifene (a SERM) stimulates in women?
Bone density
What is the only thing that Clomiphene (a SERM) stimulates in women(?
Ovulation
What are the three things Tamoxifen (a SERM) stimulates in women?
- Ovulation
- Uterine cell proliferation
- Bone density
What is the one thing that Tamoxifen (a SERM) interrupts in women?
Mammary cell proliferation
What are the 3 things Raloxifene (a SERM) interrupts in women?
- Ovulation
- Mammary cell proliferation
- Uterine cell proliferation
Why is Clomiphene (a SERM) both estrogenic and anti-estrogenic?
it is estrogenic because it stimulates pituitary release of LH and FSH that increase ovulation
Evista is the brand name for what SERM?
Raloxifene
Raloxifene protects against what fractures related to osteoporosis?
- Spine fractures
2. Not protective against hip fractures
What is an increased risk when taking Raloxifene?
Thrombophlebitis
What are 2 osteoporosis drugs that do prevent both spine and hip fractures?
- Bisphosphonates
2. Teriparatide
What are 2 physiologic functions of Parathyroid hormone (PTH)?
- Maintains calcium levels in extracellular fluid
2. Maintains integrity of parathyroid gland
If PTH maintains extracellular Calcium levels, by default what is it also maintaining?
Intracellular calcium levels
If the level of extracellular Calcium decreases, what is released by what?
PTH released by parathyroid gland to increase extracellular calcium
What hormone opposes PTH?
Calcitonin from the C-cells of the thyroid
What is the major source for PTH to harvest Calcium to increase the extracellular calcium levels?
Bone
What 2 things are released when PTH acts on bone?
- Calcium ions (Ca++)
2. Phosphate (PO4)
What are Primary, Secondary, and Tertiary sources for PTH to increase Calcium?
Primary = bone Secondary = intestine Tertiary = kidney
How does PTH get calcium from the kidney?
Resorb calcium and excrete Phosphate
What will result if pt has excess PTH with respect to the kidney?
Patient will no longer excrete phosphate (PO4) and calcium will not be resorbed causing a calcium phosphate kidney stone
What is a lab value to check for a patient with kidney stones?
PTH level
What are 2 causes of Hypoparathyroidism?
- Iatrogenic (surgery, most common)
2. Parathyroid gland disease
A person having tetany, muscle spasms, generalized convulsions, possible respiratory failure causing death could have what condition and why?
Hypoparathyroidism, no enough Calcium to control muscle contractions
Can PTH be given directly to treat hypoparathyroidism?
No, it is a peptide and very expensive
What is the treatment for hypoparathyroidism?
Vitamin D and Calcium supplement of the diet
What is the synthetic form of human PTH?
Forteo. Recombinant human PTH 1,34 (teriparatide)
When would Forteo (rhPTH 1,34) be indicated?
Hyperparathyroidism
What do chronically high levels of PTH cause?
increased osteoclast activity
What would intermittent administration of rhPTH1,34 do?
Stimulate osteoblastic activity when given intermittently. The key is the intermittent administration of rhPTH 1,34.
What are 2 causes of primary hyperparathyroidism?
- Parathyroid hyperplasia
2. Adenoma
Hypercalcemia caused by hyperparathyroidism produces what symptoms?
- Muscle weakness
2. Smooth m. dysfunction causing constipation, flatulence, anorexia, nausea, vomiting
What are 2 renal symptoms associated with Primary hyperparathyroidism?
- Hypercalciuria
- Hyperphosphaturia
(Both lead to kidney stones and calcified nephrons)