Exam2Lec7Cortisol,ThyroidHormones&GrowthHormone Flashcards
The adrenal coretx secretes what three hormones?
- Aldosterone (sodium-potassium balances)
- Cortisol
- DHEA
What is the main endogenous glucocorticoid?
Cortisol
What is the control pathway of secretion for cortisol?
Hypothalamic-pituitary-adrenal pathway
What plaus a role in mediation of long term stress?
Cortisol
Is cortisol continosly secreted?
Yes with a diurnal rhythm
Cortisol has a protective effect against ____ though permissive effect
hypoglycemia
interacts with glucagon and norepi
What are the 6 metabolic effects of cortisol?
- Promotes gluconeogenesis
- causes breakdown of skeletal muscle proteins
- enhances lipolysis
- supresses the immune system
- Causes negative calcium balance
- Influences brain fxn
- b/c its an anti0inflamatory and helps prevent organ rejection
What are the 5 regions of the adrenal gland and what does it secrete?
- Capsule
- Zona glomerulosa (aldosterone)
- Zona fasiculata (glucocorticoids)
- Zona reticularis (sex hormones)
- adrenal medulla (catecholamines)
What enzyme is important in order for cholesterrol to turn in to cortisol?
21-hydroxylase
cp450 family
A baby is born with a genetic mutation that results in a deficient of the enxyme 21-hydroxylase. Based on the the role of this enzyme in the pathway, what symptoms might you predict in the baby?
virilization because low cortisol, so less neg feedbacl inhibition
virilization: male physical features presenting on a female
Would men or women have more aromatase activity?
Women have more because we need more estrogen. It esp impt for post menop women
Briefly explain the HPA pathway for cortisol?
- Stress stimulus goes though crh in hypothal
- Ant pit releases POMC which is a larger peptide that is cleaved in ACTH
- cortisol is produced and released
- released to diff tissues like the liver for gluconeogeneis, adipose tissue for lipolysis, etc
reelased into muscle for protein catabolism, and immune system where its fxn is supressed
If you wanted to treat hyperthyroidsm what pathwayh would you want to mimic?
The circadiam rhythm (b/c cortisol concentration varies throughout the day)
Cortisol/HPA summary
a. origin
b. chemical nature
c. biosynthesis
d. factors affecting release
e. control pathway
f. whole body or tissue rxn
g. action at cellular level
h. feedback regulation
a. origin: adrenal cortex
b. chemical nature: steroid
c. biosynthesis: from chol, made on demand, not stores
d. factors affecting release: circadiam rhytm and stress incr release
e. control pathway: CRH (hypoth)->ACTH (ant pit)-> cortisol (adrenal cortex)
f. whole body or tissue rxn: incr gluc, decr immune fxn
g. action at cellular level: incr gluconeogensis and lysis, incr protein catab, blocks cytokine
h. feedback regulation: neg feedback to hypo and ant pit
What are 4 immunosupressant effects of cortisol as a therapeutic drug?
- supreses the IS
- inhibits the inflammatory respone
- treats allergies
- helps prevent rejection of organ transplant
If you give endogenous cortisol (glucocorticoid) what can occur?
Shut down ACTH production and adrenal cells producing adrenal cells atrophy (no atrophine)
What cortisol pathology can result from hypercortisolism?
too much cortisol
- Adrenal tumor that autonomously secretes cortisol
- Pit tumor that autonomouslty secretes ACTH-Cushings
- Iatrogenic (physician caused)-cushinfs
What cortisol pathology can result from hypocortisolism?
too little cortisol
Hyposecretion of all adrenal steroid hormones-addison disease
what are 2 clinical manifestations of cushings?
moon face (red cheeks)
abdominal fat with striations
Association b/w stress and immune fxn appears to be mediated through?
CRH and ACTH
What are 3 characteristics of CRH?
- decr food intake
- association with signals that mark the onset of labor
- links to several mood disorders (anxiety and depression)
ACTH and melanocortins
____ undergoes post-translational processing to produce a variety of biologically active peptides
POMC (pro-opiomelanocortin)
What is apart of POMC?
- ACTH and B-endorphin (endog opido), peptides produces in pituitary
- Non pituitary tissues create MSH
- Melanocortins: MSH hormones and ACTH
msh- melanocyte stimulting hormone
melanocirtins is resp for the “tan” color in addison disease
What is the fxn of alpha-MSH?
Inhibits food intake and acts on melanocytes which contain pigments called melanins
Explain the HPA pathway for post-translational processing of POMC
- POMC gets cleaves and in pituitary becomes ACT, gamma liptropin, and gamma endorphon.
- ACTH can get cleaves and in non-pit tissues becomes alpha MSH.
- Alpha MSH can do melanin synthesis, initiate immune respnse, and decr food intake
what can have long term effects on metabolism, less essential in adullts, but is very essential for growth and development in children and infants?
Thyroid hormones
Where is thyroid hormone synthesized and what is the center filled with?
- Synthesis takes place in the colloid of thyroid follicles
- Center is filled with colloid (string of T3/T4) which holds supply of hormones
colloid is a glycoprotein
What secretes thyroid hormone?
Follicular cells
What is thyroglobulin?
A glycoprotein made in follicular cells (outside colloid)
polymer of T3 and T4
What molecule is concentrated in the colloid with the help of NIS and pendrin?
Iodine
very impt b/c added to tyrosine
NIS is a Na+ and Iodine supporters that moves iodine into follicle and pendrine moves iodine into colloid
Where is the thyroid gland locates and what does it secrete?
Located below the larynx and secretes thyroid hormones and calcitonin
calcitonon-another hormone produced by thyroid
