Block 2: Endocrine II Quiz Gms 6419
Block 2: Endocrine II Quiz Gms 6419
Situation # 1 A man has renal failure and is maintained on chronic hemodialysis until a donor
kidney can be found.
1. This man exhibits increased circulating levels of PTH. Why?
A. Because of increased excretion of phosphate by the kidneys, leading to lowered circulating
PO4-
B. Because of a lack of conversion of 25-(OH)D3 to 1,25-(OH)2D3 in the liver
C. Because of increased absorption of calcium and phosphate from the intestine into the blood,
and increased circulating Ca2+
D. Because of a lack of 1,25-(OH)2D3 production by the kidneys, and therefore no inhibitory
action of this Vitamin D metabolite on PTH synthesis by the Chief Cells D
renal failure results in the inability to excrete PO4- so phosphate levels are raised -> resulting in
complexed Ca++ and lowered plasma calcium
& high levels of PO4- inhibit calcitriol metabolism, causing the inactive metabolite of VitD
(24,25(OH)2D3 to be formed instead
calcitriol has a (-) feedback mechanism at the parathyroid - it switches off PTH synthesis and
increases CaSR synthesis in the chief cells
w/o the (-) feedback mechanism PTH syn/sec goes unchecked -> increased circulating PTH
2. Assuming that this person is receiving good medical care, which of the following would be an
essential supplement to his hemodialysis.
A. Daily injections of 25-(OH) D3
, B. Plenty of exposure to sunlight
C. Chronic administration of rhPTH (Forteo)
D. Administration of 1, 25-(OH)2 D3
E. A diet rich in Vitamin D3 D
administration of calcitriol [1,25 (OH)2D3]
3. Injection of calcitonin into this man during his maintenance period on
hemodialysis would cause:
A. A large excretion of calcium in the urine
B. Inhibition of bone breakdown
C. Increased synthesis of 25-(OH) D3
D. Increased production of 1, 25-(OH)2 D3
E. A large increase in bone resorption calcitonin - tones down calcium in blood inhibits
bone resorption & stimulates Os.b
B
1. Growth hormone has several direct and indirect actions. Which one is indirect action?
a. Increases in collagen synthesis
b. Decreased glucose uptake
c. Reduced lipogenesis
d. Reduced protein synthesis
e. None of the above a
collagen synthesis is mediated by IGF
Block 2: Endocrine II Quiz Gms 6419
Situation # 1 A man has renal failure and is maintained on chronic hemodialysis until a donor
kidney can be found.
1. This man exhibits increased circulating levels of PTH. Why?
A. Because of increased excretion of phosphate by the kidneys, leading to lowered circulating
PO4-
B. Because of a lack of conversion of 25-(OH)D3 to 1,25-(OH)2D3 in the liver
C. Because of increased absorption of calcium and phosphate from the intestine into the blood,
and increased circulating Ca2+
D. Because of a lack of 1,25-(OH)2D3 production by the kidneys, and therefore no inhibitory
action of this Vitamin D metabolite on PTH synthesis by the Chief Cells D
renal failure results in the inability to excrete PO4- so phosphate levels are raised -> resulting in
complexed Ca++ and lowered plasma calcium
& high levels of PO4- inhibit calcitriol metabolism, causing the inactive metabolite of VitD
(24,25(OH)2D3 to be formed instead
calcitriol has a (-) feedback mechanism at the parathyroid - it switches off PTH synthesis and
increases CaSR synthesis in the chief cells
w/o the (-) feedback mechanism PTH syn/sec goes unchecked -> increased circulating PTH
2. Assuming that this person is receiving good medical care, which of the following would be an
essential supplement to his hemodialysis.
A. Daily injections of 25-(OH) D3
, B. Plenty of exposure to sunlight
C. Chronic administration of rhPTH (Forteo)
D. Administration of 1, 25-(OH)2 D3
E. A diet rich in Vitamin D3 D
administration of calcitriol [1,25 (OH)2D3]
3. Injection of calcitonin into this man during his maintenance period on
hemodialysis would cause:
A. A large excretion of calcium in the urine
B. Inhibition of bone breakdown
C. Increased synthesis of 25-(OH) D3
D. Increased production of 1, 25-(OH)2 D3
E. A large increase in bone resorption calcitonin - tones down calcium in blood inhibits
bone resorption & stimulates Os.b
B
1. Growth hormone has several direct and indirect actions. Which one is indirect action?
a. Increases in collagen synthesis
b. Decreased glucose uptake
c. Reduced lipogenesis
d. Reduced protein synthesis
e. None of the above a
collagen synthesis is mediated by IGF
