Test 1 review Flashcards
How does somatostatin affect the pituitary?
inhibits GHRH from hypothalamus –> inhibits GH
What are actions of GH via IGF?
increased protein syn in chondrocytes –> linear growth
increased protein syn in muscle –> increased lean body mass
increased organ size
How can growth hormone excess be treated?
via somatostatin analogues –> will inhibit GHRH –> inhibit GH
Where do ADH and oxytocin originate (specifically)?
ADH = Supraoptic nuclei (SON)
oxytocin = Paraventricular nuclei (PVN)
What do the different ADH receptors do?
V2 receptor (Gs) –> adds aquaporins into principle cells of CD and late distal tubule
V1 receptor (Gq) –> constricts smooth muscle
what is the Wolff-Chaikoff effect?
high levels of I- inhibit organification and coupling reactions of I2
inhibits synthesis of thyroid hormone
What does thyroid deiodinase do?
What does deficiency of it look like?
removes I2 from leftover MIT and DIT in follicular cells –> I can be used to make more T3 and T4
deficiency = looks like I2 deficiency (Iodine gets sequestered in MIT and DIT)
What converts T4 to T3 in peripheral tissues?
5’-iodinase
How are bone and thyroid hormone related?
Thyroid hormones act w/ GH and somatomedins to promote bone formation
THs also stimulate bone maturation - in thyroid hormone deficiency, bone age is less than chronological age
What stimulates ACTH and by what receptor?
CRH via Gs –> cAMP –> ACTH
What are the basic anti-inflammatory effects of glucocorticoids?
induce syn of lipocortin –> inhibits phospholipase A2 = precursor for prostaglandins and leukotrienes
inhibits production of IL-2 –> inhibits T cell proliferation
inhibit release of histamine and serotonin from mast cells and platelets
How does cortisol affect vasoconstriction?
upregulates alpha1 receptors on arterioles –> increase vasoconstrictive sensitivity to NE –> BP increases
How does glucagon increase gluconeogenesis?
decreases production of fructose 2,6-bisphosphate –> decreases phosphofructokinase activity –> substrates are directed toward glucose formation rather than breakdown
What is thyroid hormone’s mechanism of action on cells?
steroid hormone moa
Where is Ca reabsorbed and Pi excreted in the kidney due to PTH?
Ca reabsorbed in distal tubule
Pi excreted more in proximal tubule
What specific things does PTH do in the kidney in regard to Ca?
in DCT
stimulates TRPV5 on apical membrane to bring in Ca
stimulates Na/Ca exchanger on basolateral membrane
How does PTH stimulate Pi excretion?
in PCT:
FGF23 goes to basolateral membrane to Gs –> inhibits Na-Pi symporters on apical membrane
Where are CaSR in the kidney?
TAL
What are the Basophils in the Ant Pit?
B FLAT
Basophils - FSH, LH, ACTH, TSH
What things occur via the Ras-dependent path from insulin signaling?
cell grown, DNA synthesis
What things occur via the RAS-independent/Pi3K path of insulin signalling?
glycogen, lipid, protein synthesis –> move GLUT4 to membranes
Where is GLUT4 found?
adipose tissue
striated muscle
How do you remember what cortisol does?
cortisol is A BIG FIB
Appetite increased
Blood pressure
Insulin resistance
Gluconeogenesis, etc
Fibroblast activity inhibited
Immune suppression
Bone formation down
What things can inhibit peripheral conversion of T4 to T3?
glucocorticoids
beta-blockers
PTU
