Flashcards in Adrenal Gland Phys Deck (52):
1
Adrenal Gland composed of what two areas?
Cortex and Medulla
2
Adrenal cortex is located where in relation to the medulla
Periphery
3
What types of hormones does the adrenal cortex make?
Steroids
4
Three regions of the adrenal cortex
zona glomerulosa (15%)
zone fasiculata (75%)
zona reticularis (10%)
5
What does the zona glomerulosa make?
Aldosterone
6
What do the zona fasiculates and zona reticularis make?
Glucocorticoids (cortisol), SAndrogens and Estrogens
7
Adrenal Medulla makes?
Catecholamines (Epinephrine and Norepinephrine)
8
See slides and hormone table bs for function of the hormones
ok
9
Transport of adrenocortical hormones in blood is facilitated by what?
steroid hormone-binding serum proteins called GLOBULINS
-partially by albumin which has low affinity
10
90% of Cortisol exists in what form
BOUND, moslty to transcortin and partially to albumin
11
10% of cortisol in plasma is :
FREE
12
60% of aldosterone is bound to?
Transcortin
13
Purposes of hormone binding protein:
- suppress the biological activity of steroid hormones
- protect the hormone from structural alteration
- Extend the half-life of hormones
- Provide an active hormone to the target tissue when needed
14
What is teh source of all steroid hormones
cholesterol duh.
15
What provides the cholesterol
LDL (80% cholesterol for steroid synthesis)
16
How cholesterol get into adrenal cells for steroid synthesis
LDL binds to LDL receptors (clathrin coated pits) on the plasma membranes of adrenal cortical cells
17
LDL is transported into the cells by what process
endocytosis (endosomal membrane trafficking)
18
In lysosomes cholesterol is released from the receptors
ok
19
Cholesterol is then esterified and stored in cytoplasmic vesicles until it is needed for steroid synthesis
ok
20
Key enzyme in steroid synthesis
KNOW
cholesterol desmolase (cyp11A1) part of the P450 superfamily
- facilitates the conversion of cholesterol to pregnenolone
21
What controls steroidogenesis
ACTH stimulates CYP11A1
- also stimulates cholesterol uptake by upregulating LDL receptors
22
Besides Desmolase, what is the other key enzyme in mineralocorticoid biosynthesis
Aldosterone Synthase
23
What upregulates desmolase activity?
ACTH...you know this
24
What upregulates aldosterone synthase
Ang II
25
What is the final step of mineralocorticoid biosynthesis?
corticosterone to aldosterone
26
Target organs for aldosterone
kidneys, brain, lungs, heart, vascular
27
What is the mechanism of mineralocorticoid effect?
Upregulates gene expression:
1) binds to MR's in the cytoplasm
2) The hormone receptor complex translocates to the nucleus
3) Binding to the promoter area of specific genes
4) Upregulation of gene expression (Na/K ATPase, Na, K transporters
28
Genes that are upregulated by the mineralocorticoids?
- Na/K ATPase...ATP dependent transport of Na and K
- Epithelial sodium channel (ENaC
- Serum and Glucocortocoid regulated kinase 1 (SGK1)
- Renal outer medullary K channel
---Important to note that SGK1 activates Na/K ATPase, ENac, and ROMK)
29
GLucocorticoids are produced where?
Zona Reticularis and Zona Fasiculata (main site of synthesis)
30
most potent glucocorticoid
Cortisol (hydrocortisone)...95% os glucoccorticoid activity
31
Corticosterone
modest potency
32
What are the key enzymes in cortisol biosynthesis that we should know
- cholesterol desmolase
- 11beta hydroxylase
33
What drug inhibits desmolase action?
ketaconazole
34
What drug inhibits 11beta hydroxylase action
Metapyrone and Etomidate
35
Glucoccorticoids (cortisol) affect on the liver
promotes gluconeogenesis from amino acids, mobilization of amino acids from muscle into blood
36
Cortisol on pancreas?
upreg insulin production
37
cortisol's affect on various organs?
Upregulate insulin resistance
38
KNOW that glucocorticoids stimulate protein catabolism in all organs except the liver
ok. This means that proteins are broken down to amino acids, you have more amino acids in the blood, decreased protein synthesis mean sloss of body wt. and immune function suppresed
39
Gluccocorticoids and fat metabolism
Promotes lipolysis, enhance mobilization and oxidation of fatty acids as an alternative enrgy source.
-Redistribution of body fat (paradoxical fat deposits in the body)
40
High doses of oral cortisol can lead to what?
Cushing's syndrome
41
What does Cortisol do to immune function
Suppresses it
42
EFFEcts of Cortisol on other tissues
notes
43
Describe transactivation and transpression as they apply to glucocorticoid effect on gene expression
transactivation- stimulation or repression of gene expression
transpression- suppression of genes via transcriptional factors
44
Adrenal sex hormones and males
weak effects
45
Adrenal sex hormones in women
The major Androgens (excess leads to suppression of gonadal function and masculinization) This is called adrenogenital syndrome
46
The hormones of the adrenal medulla are?
Epinephrine, Norepinephrine
47
What is the structure of epinephrine and norepinephrine?
amino acid derivatives (tyrosine)
48
Remember that the cells of the medulla are neuroectodermal in origin and therefore are modified neurons
ok
49
Targets of catecholamines?
heart, lungs, muscles, vessels
50
Hypothalamic pituitary adrenal axis does what?
manages tress response, energy usage, immune response, digestion
51
Corticotrophin releasing hormone stimulates the pituitary to secrete ACTH
ACTH stimulates the adrenal cortex to produce its hormones....KNOW
52