Lecture & Vodcast 3 -- Exam 5 Flashcards
What hormone does zone 1 (Glomerulosa) in the adrenal gland secrete?
aldosterone
What hormone does zone 2 (fasciculata) in the adrenal gland secrete?
cortisol
What hormone does zone 3 (reticularis) in the adrenal gland secrete?
epinephrine and testosterone
** main source of epinephrine
What is the precursor for aldosterone, cortisol and testosterone?
cholesterol
When making aldosterone, cortisol and testosterone, cholesterol is converted into _______________ in the adrenal gland
pregnenolone
When making aldosterone, cortisol and testosterone, cholesterol is converted into pregnenolone by what enzyme in the adrenal gland?
P450 Scc
What enzyme does zone 1 (aldosterone) and zone 2 (cortisol) share when making these hormones in the adrenal gland?
21 hydroxylase
What is the enzyme zone 1 needs to make aldosterone and is the final enzyme before aldosterone is created in adrenal gland?
P450 aldosterone synthase
Does high or low Na+ passing through the glomerula (zone 1) in adrenal gland induce synthesis of aldosterone?
low Na+
** will stimulate reaborption
_____ is the actual stimulator for aldosterone secretion and not Na+ levels because its the one that binds to zone 1 cells to induce aldosterone secretion in adrenal gland
AT II
______kalemia causes opening of Ca2+ channels on zone 1 cells to start the second messenger pathway for aldosterone synthesis in adrenal gland.
hyperkalemia
What are the 4 roles of aldosterone in zone 1 of the adrenal gland?
- increase apical Na+ channels (for absorption)
- increase basolateral Na/K ATPase (for absorption)
- increase ATP (for step 2)
- increase apical K+ channels (K+ secretion)
___________ blood volume triggers zone 1 cells
decreased
What are the 3 hormones for the hypothalamic-pituitary-adrenal axis?
hypothalamus: CRH
pituitary: ACTH
adrenal: cortisol
_______glycemia induces cortisol secretion
hypoglycemia (cortisol raises BG)
What is cortisols main function?
raise blood glucose
_______ from the pituitary stimulates release of cortisol in the adrenal gland
ACTH
______ can feedback in a short loop fashion to stop CRH secretion from hypothalamus
ACTH
** short: pituitary –> hypothalamus
cortisol can feedback in a long loop fashion to stop ______ secretion from the hypothalamus
CRH
** long loop: periphery gland –> hypothalamus
What lipid binds to zone 2 cells when ACTH binds and is needed because its the precusor for the zone 2 hormone?
LDL (cholesterol)
When does cortisol peak the most?
right when you wake
** long fast
Cortisol secretion follows _______ patterns
feeding
- rises between meals
What is cortisol’s affect on fat?
increases breakdown except in stomach
* to raise BG
What’s cortisol’s affect on protein synthesis?
decreases synthesis
* to raise BG
Why does cortisol seem to break everything down for glucose except it increases glycogen storage?
stores some glucose to prevent hyperglycemia
How does cortisol affect the immune system?
suppresses it
What is the precursor for epinephrine in zone 3 of the adrenal gland?
tyrosine
What enzyme converts tyrosine to DOPA when synthesizing epinephrine in zone 3 of the adrenal gland?
tyrosine hydroxylase
What nervous system stimulates the function of tyrosine hydroxylase in zone 3 of adrenal gland?
SNS
** remember we are producing epinephrine
What enzyme converts norepinephrine into epinephrine in the zone 3 of adrenal gland?
PNMT
Why is cortisol needed to convert norepinephrine into epinephrine even though these hormones are made in 2 different zones of the adrenal gland?
blood supply to the adrenal gland passes through zone 2 before it gets to zone 3 so cortisosl is carried
Is the an aldosterone deficiency or excess?
salt craving
low sodium
acidosis
dehydration
deficiency
Is the an aldosterone deficiency or excess?
Na+ retention
hypokalemia
hypertension
excess
What is Addison’s disease?
autoimmune destruction of adrenal gland
What is the affect of aldosterone and cortisol levels in Addison’s disease?
decreased
Does Addison’s disease cause increasing weight or decreasing weight?
decreasing
- cannot regulate hunger due to low cortisol levels
Does Addison’s disease cause high or low blood glucose?
low (no cortisol to increase it)
What is affect of ACTH levels in Addison’s Disease?
high because the adrenal gland is what is messed up so no cortisol is being produced causing excessive secretion of ACTH by pituitary
What is Cushing’s syndrome?
excess cortisol
In Cushing’s syndrome, what are the levels of ACTH, cortisol, and adrogens?
increased
What would happen to ATII and ACTH and testosterone levels if there is a 21-hydroylase deficiency?
ATII and ACTH would be high (they are upstream of issue) which drives production of pregnenolone (precursor for adrenal cortisol and adlosterone) which will make a TON of testosterone
What do alpha cells produce in the pancreas?
glucagon
What do beta cells produce in the islet of the pancreas?
insulin
What do delta cells produce in the islet of the pancreas?
somatostatin
The islets of the pancreas receive stimulation for para sympathetic and sympatheic NS because cells there produce ________ and _________
insulin
glucagon
What is the role of glucagon?
What about insulin?
glucagon: raise BG
insulin: lower BG
What are the 2 ways glucagon can raise BG?
glycogenolysis
gluconeogenesis
Where are most of glucagon’s effects felt?
liver
Why does glucagon function the most in the liver?
first location glucagon goes when its released
Is hexokinase inhibited or activated in glucagon conditions?
inhibited (dont want to uptake glucose)
Does glycogen levels increase or decrease in glucagon conditions?
decrease (breaks it down for glucose)
Is acetyl coA carboxylase inhibited or activated in glucagon conditions?
inhibited to prevent malonyl coA from storing glucose as triglycerides
What happens to malonyl coA if glucagon has inhibited cetyl coA carboxylase?
it goes through beta oxidation to generate ketone bodies
Rising ketone levels turn off _______ to prevent ketoacidosis
glucagon
What glucose transporter is insulin-independent?
GLUT2
What is the role of the ATP-sensitive K+ channels in insulin secretion?
formation of ATP (from glycolysis products) closes K+ channel which allows for an influx of Ca2+ = depolarization = release of insulin
When glucagon is high it can stimulate ________ to prevent hyperglycemia
insulin
__________ ________ can activate insulin and glucagon
amino acids
When insulin binds to its receptor it phosphorylates IRS which induces transcription of ….
GLUT 4
What glucose transporter is insulin-dependent?
GLUT4
What tissue type has GLUT 4?
muscle tissue (prevents excessive glucose uptake)
adipose tissue
Why can glucose never leave muscle cells?
it doesn’t have a G6Pase
What is insulin’s affect on lipids in muscle tissue?
increases lipogenesis
What is insulin’s affect on protein synthesis in muscle tissue?
increases
What tissue contains GLUT2?
liver
What is insulins affect on glycogen in the liver?
increases storage
What is insulin’s affect on acetyl coA carboxylase?
increases it = increased triglyceride
Somatostatin is not a primary regulator of insulin and glucagon because it’s meant for _______ __________
fine tuning
Glucagon __can/can’t__ directly stimulate insulin but insulin ___can/can’t___ stimulate glucagon
can
can’t
Do type I diabetics have high or low insulin levels?
low
* destruction of beta cells
Do type I diabetics have high or low ketone bodies?
high
* no insulin to turn it off
Do type I diabetics have insulin resistance?
no
How does metformin function as a diabetic drug?
reduces liver gluconeogenesis
How does Sulfonylureas function as a diabetic drug?
blocks ATP-sensitive K+ channel to induce insulin secretion
* increases intracellular ca2+ to induce insulin secretion
How does DPP-4 inhibitors function as a diabetic drug?
reduces gluconeogensis in liver
blocks DPP-4 = more insulin
How does SGLT2 inhibitors function as a diabetic drug?
increases glucose excretion
How does GLP-1 agonist function as a diabetic drug?
synthetic GLP-1 increases insulin secretion
reduces gastric emptying
