Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biochem ENDO > Hormone Action II > Flashcards

Hormone Action II Flashcards

1
Q

what is the “master control center” of the endocrine system?

why is this the case?

A

the hypothalamus

is the integration of the nervous system + endocrine system

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is the target organ of the hypothalamus?

A

the pituitary gland

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

discuss the chemical structure of hypothalmic hormones.

why is this important?

A
  • N - terminus: is cyclic: this bulkiness protects hypothalmic hormones (which are small) from degradation in the blood
  • C - terminus: is an amide group that links a hormone specific peptide chain through its carbonyl. as a result, there is no “free” COOH group

both of these features extend the half life of hypothalmic hormones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

hypothalmic hormones bind to:

  • what receptors?
  • inducing an intracellar response in what way?
A
  • GCPRs (Gq) on the ant pituitary (adenohypophysis)
  • Gq –> PLC –> IP3 + DAG –> increasing Ca++ and PKC
    • ​this stimulates exocytosis of pre-existing vesicles into blood stream
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

list the ant pituitary (adenohypophysis) hormones released by the following hypothalmic hormones:

  • TRH
  • PRF
  • PIH
  • CRH
  • GnRH
  • GHRH
  • Somatostatin
A
  • thyrotropin releasing hormone –> TSH (+ prolactin?)
  • prolactin stimulating hormone –> prolactin
  • prolacting nhibiting hormone (dopamine) –> inhibits prolactin release
  • corticotropoic releasing hormone –> ACTH
  • gonadotropin releasing hormone –> LH & FSH
  • growth hormone releasing hormone –> GH
  • somatostatin –> inhibitrs GH release
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

whwat are the six hormones released by the ant pituitary (adenohypophysis) and where do they each act?

A

acidophiles = lactotrophes (prolactin) & somatotrophes (GH)

basophiles = corticotrophes (ACTH), gonadotrophes (LH & FSH) & thyrotrophes (TSH)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

which pituitary hormones act on the JAK-STAT receptor?

what chemical structure category do these hormones fit into?

A

both are proteins

  1. GH
  2. prolactin

induces dimerization –> JAK-P - intracellular chain-P - STAT recruitement - STAT-P (by JAK)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

which pituitary hormones act on the Gs receptor?

what chemical structure categorization do these hormones they fall into? describe their structure.

A
  1. TSH
  2. FSH
  3. LH
  • all are glycoproteins ​made of alpha-beta dimer:
    • a subunits are the same for all three each hormones
    • b subunits have the unique. hormone-dependent aa sequence
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q
  • what is POMC?
  • where is it produced?
  • what is its purpose?
A
  • pro-opiomelanocortin
  • produce in ant pituitary (adenohypophysis) & intermediate pituitary
  • serves as a precursor hormone for:
    • ACTH
    • MSH
    • lipotropin
    • endodorphins
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

pro-opiomelanocortin (POMC) is a precursor for which hormones?

breifly, what do each of these horones do?

A
  1. ACTH: made in response to CRH, acts on adrenal cortex to induce glucocorticoid synthesis
  2. MSH (melanin stimulating hormone): stimulates melanin synthesis in skin
  3. endorophin: decrease pain reception causing euphoria
  4. lipotropin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

POMC processing involves

  • what modifications?
  • at what sequences?
  • based on?
A
  • glycosylations + acetylations + extensive proteolytic cleavage
  • basic protein sequences
  • POMC cleavages (and product produced) based on proteolytic activity expressed by the ant pituitary cell type receiving it
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

the posterior pituitary (neurophysis) produces what hormones?

what do these hormones have in common?

what are their individual roles?

A
  • technically does not produce any hormones
  • stores two hormones produced by hypothalmic neurons:
    • which are:
      1. oxytocin - stimulates lactation and uterine contraction (during delivery)
      2. vasopressin (ADH) - regulate body osmolarity
    • both:
      • are cyclic nonaptides
      • are bound by neurophysins (carrier proteins) in the blood
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what are neurophysins?

A

carrier proteins that associated with oxytocin and vasopressin (ADH)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

how would a dietary deficiency of iodide affect the thyroid hormone cascade?

A
  • would decrease production of T3 & T4 which would
    • increase production of TRH (hypothalamus)
    • increase production of TSH (anteiror pituitary)

(negative feedback)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

discuss the steps & molecules involved in iodide oxidation

A
  • iodide taken up into folliclular cell cytoplasm using a Na/K ATPase
  • iodide oxidaized to iodine to thyroperoxidase
  • iodine secreted into lumen, then added to tyrosine residues on thyroglobulin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

after thyroglobulin gets iodinated - what steps occur next in the synthesis of thyroid hormones?

A
  • ionization of residues forms DIT and MIT molecules (DIT = two Is on a tyrosine residue, MIT = one I on a tyrosine residue)
  • ionidonated thyroglobulin is stored in the colloid until TSH stimulates follicular cells to:
    • uptake colloid to bring along iodinated thyroglobulin, which becomes fused to vesicles
    • lysosomes degrade the iodonated thyroglobulin to release T3 (MID + DIT) and T4 (DIT + DIT)
17
Q

is T3 or T4 more active?

A

T3

18
Q

how are T4 and T3 transported to target tissues & why is this significant?

what kind of receptors do they bind to?

describe this binding.

A
  • T3 and T4 are thyroid hormones and thus lipophillic
    • they require protein carriers - thyroxin binding globulin (TBG) and thyroxin binding pre-albumin (TPBA) which will
      • increase their half life by 99%
      • then drop them off at their receptors, which are
        • nuclear receptors (subclass II)
          • binding is “non-covalent”
          • if T4 (less active thyroid hormone) is bound, it will be converted to T3 by a deiodinase
19
Q

what is the role of diodinase and where is it found?

A
  • found in target tissues of thyroid hormones
  • convert T4 to T3 (more active form)
20
Q

what is rT3?

A

the inactive form of thyroid hormones

21
Q

what are the means by which thyroid hormones inactivated?

A
  • conversion of T4 –> rT3
  • glucaronidation
  • de - ionidation / carboxylation / amination

Biochem ENDO (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions