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Biochemistry of Hormones
EXAM 2
51
Medical
Professional
09/02/2010

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Term
what are the three general classes of hormones?
Definition
peptide, tyrosine derivatives, and steroid hormones
Term
which non steroid can diffuse through the membrane and bind to nuclear receptors?
Definition
thyroid
Term
where are steroids derived from?
Definition
cholesterol
Term
what are the classes of the steroid hormones
Definition
glucocorticoid, mineralcorticoid, and sex hormones
Term
what is an example of glucocorticoid?
Definition
cortisol
Term
which non steroidal hormones belong to the steroid receptor super family?
Definition
thyroid, active metabolite of vit D3, and retinoic acid.
Term
where does a hormone stimulus originate?
Definition
external environment, or chemical signals and AP
Term
what is the pathway of the hormone signaling
Definition
limbic system-->hypothalamus-->pituitary-->target gland
Term
what is the function of cortisol?
Definition
it promotes reabsorption of Na in the kidney by acting on a Na/H antiporter
Term
corticosteroids have three functions and they are
Definition
Na uptake, stress adaptation, anti-inflammatory and immunosuppresive effects
Term
what gene produces the ACTH
Definition
POMC which is cleaved by AP to release ACTH and B-lipotropin.
Term
what product can be derived from the POMC gene?
Definition
ACTH, MSH, B-lipotropin, and beta endorphins
Term
where does ACTH stimulate specifically in the adrenal gland?
Definition
zona fasiculata-->GCs, cortisol and corticosterone.
Term
binding of ACTH causes what pathway?
Definition
adenylate cyclase-->cAMP-->PKA
Term
what is the effect of PKA in the adrenals?
Definition
increases mobilization and delivery of cholesterol to the inner mitochondrial membrane.
Term
what is converted to cortisol once PKA is activated
Definition
Pregnelol
Term
what does increased cAMP promote in the adrenals?
Definition
transcription of the StAR protein
Term
what is the function of the StAR protein
Definition
facilitates the translocation of cholesterol from the outer to inner membrane
Term
what does cortisol induce the release of
Definition
epinephrine
Term
where is epinephrine located?
Definition
chromaffin cells of the medulla
Term
what is the function of PNMT
Definition
converts NEP to EP
Term
what effect does cholesterol have on bone?
Definition
it increases turnover which can lead to osteoporosis.
Term
how does TSH bind in the cell
Definition
Adenylate Cyclase pathway
Term
where are TG vesicles secreted from?
Definition
Golgi
Term
When TG crosses over the apical membrane, TG combines with Iodine to form T3,4 complex. what is the enzyme that catalyzes this
Definition
peroxidase
Term
what removes DIT and MIT from the T3,4 complex inside the cell
Definition
deiodinase, which removes the iodine.
Term
how is DIT and MIT cleaved from the complex?
Definition
proteases
Term
synthesis and structure of the thyroid hormone
Definition
1. Iodine is oxidized by peroxidase
2. I2 + tyrosine->MIT or DIT
3. DIT + DIT->T4
4. DIT + MIT->T3
Term
how does T3, 4 increase metabolic rate
Definition
increasing activity of Na/K ATPase and mitochondrial oxidative metabolism
Term
what cells do FSH act on?
Definition
Sertoli cells
Term
what is the function of FSH in the seminiferous tubules?
Definition
it increases the production of androgen binding protein
Term
what is the function of ABP?
Definition
helps maintain high androgen levels in the testis important for development of sperm
Term
what does the hypothalamus release in response to growth hormone
Definition
release of somatostatin
Term
explain the GH pathway?
Definition
GH->IGFs (from liver)->somatic cell growth
Term
what is the effect of GH on adipose tissue
Definition
fat mobilization
Term
what is the effect of GH on muscle
Definition
increased protein synthesis
Term
what effect does the GH have on the liver?
Definition
increased gluconeogenesis
Term
what is the pathway of GH
Definition
Adenylyl Cyclase
Term
how are GH deficiencies corrected in adults?
Definition
GH replacement therapy
Term
Vasopressin is encoded with this other gene
Definition
neurophysin II
Term
how is ADH released?
Definition
stimuli from OSMORECEPTORS resulting in an increase in extracellular salt conc.

baroceptors responding to fall in BP.
Term
where are ADH and neurophysin stored?
Definition
nerve endings of hypothalamic neurons that project to the posterior pituitary gland
Term
function of ADH
Definition
causes water reabsorption into the blood stream which causes increase in blood pressure
Term
where specifically does ADH act on the kidney?
Definition
distal tubule
Term
what is the pathway of ADH
Definition
Adenylyl cyclase
Term
what is pituitary diabetes insipidus due to
Definition
lack of vasopressin (mutaions, head trauma)
Term
nephrogenic diabetes insipidus is
Definition
decreased renal response to ADH secretion
Term
these hormones induce aldosterone release by the glomerulosa
Definition
angiotensin 1 and 2
Term
how does angiotensin 2 increase BP
Definition
constricts vascular smooth muscle
Term
angiotensin pathway
Definition
PLC
Term
what is the effect of Ach on aldosterone secretion
Definition
increase secretion of aldosterone
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