Biochem 1: hormone action Flashcards

1
Q

Where are endocrine hormones secreted into

A

the blood

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2
Q

True or False: endocrine hormones travel to distant sights of action

A

True

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3
Q

What is an endocrine hormone

A

chemical secreted by cell or group of cells into the blood

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4
Q

What are the general characteristics of endocrine hormones

A
  1. work on multiple tissues
  2. work at relatively low concentrations
  3. Have to bind to receptors on either cell surfaces or intracelluar
  4. Ellicit non-genomic or genomic responses
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5
Q

What are the 2 major classes of hormone receptors

A
  1. cell surface receptor

2. intracellular receptor

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6
Q

Intracellular receptors can be subdivided into 2 types, what are they

A
  1. cytosolic

2. nuclear

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7
Q

What do hormonal responses depend on?

A
  1. R availability
  2. hormone concentration
  3. affinity for the receptor
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8
Q

What happens with cytosolic receptors

A

translocates to the nucleus after binding of ligand

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9
Q

What happens with nuclear receptors

A

since its already in teh nucleus, it is directly associated with DNA and gene they are regulating

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10
Q

cell surface receptors lead to…

and how do they do it

A

rapid, non genomic responses
by altering protein functions

however, can have genomic response BUT often occurs through a CASCADE EFFECT

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11
Q

Intracellular receptors lead to…

and how do they do it

A

delayed, genomic responses

by altering gene expression

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12
Q

How many transcription factors domains are associated with intracellular steroid receptor

A

4

DNA binding domain 
ligand biding domain
Dimerization domain 
Trans-activation domain 
(cytosolic only) nuclear localization signal
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13
Q

What is the DNA binding domain

A
  1. binds the receptor/ligand complex to the DNA sequence needed to regulate the gene of interest
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14
Q

What are also seen in the DNA binding domain

A

Zinc fingers - allows for binding to DNA in proper oreintation
so that the TF’s can bind the recptor complex and regulate gene expression

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15
Q

What is the Ligand binding domain

A

the portion of the receptor that binds the hormone

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16
Q

What is the dimerization domain

A

allows for the dimerization of receptor/ligand complex

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17
Q

Dimerization is often needed for…

A

the correct function of TF/R complexes

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18
Q

TRUE or FALSE : is dimerization domain seen in all steroid receptors

A

FALSE

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19
Q

What is the trans-activation domain

A

portion that binds to transcriptional regualtor proteins

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20
Q

What is the nuclear localization signal

A

allows for the targeting of the ligand/receptor complex to the NUCLEUS

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21
Q

Where are the sites of hormone production in the Endocrine system

A
  1. hypothalamus and pituitary gland
  2. thyroid and parathyroid
  3. adrenal
  4. pancreas
  5. ovaries and testes
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22
Q

What are the 3 main categories of hormones based on chemical classification

A
  1. protein/peptide
  2. steriod
  3. amino acid
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23
Q

What are the 3 main categories of hormones based on chemical classification

A
  1. protein/peptide
  2. steriod
  3. amino acid
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24
Q

what are protein/peptide made from

A

gene expression of protein expressing genes (In other words they are made of Proteins)

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25
Q

The majority of hormones are (BLANK) hormones

A

protein/peptide

especially those from the pituitary

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26
Q

what are protein/peptide made from

A

gene expression of protein expressing genes

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27
Q

The majority of hormones are (BLANK) hormones

A

protein/peptide

especially those from the pituitary

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28
Q

Are protein/peptide hormones water soluble or insoluble

A

soluble

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29
Q

TRUE or FALSE: protein/peptide hormones have a quick half-life

A

TRUE; minutes

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30
Q

Which receptors do they usually bind to

A

cell surface receptors

and leads to rapid response

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31
Q

channels, enzymes, transport can be altered by which hormone

A

protein/peptide

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32
Q

protein/peptide hormone response is dependent on what 3 facotrs?

A
  1. hormone concentration
  2. availability
  3. affinity of receptor for ligand
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33
Q

can protein hormones be made in advanced? why?

A

yes, bc they can be stored in vesicles and released when needed

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34
Q

What is the first step in synthesizing protein/peptide hormone

A

pre-prohormone is made in the RER

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35
Q

how is pre-prohormone made

A

mRNA on ribosome binds aa into a peptide chain

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36
Q

What happens to pre-prohormone

A

its modified in the ER to PROHORMONE due to removal of a signal sequence, which makes it inactive

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37
Q

Where do the prohormones go to next

A

goes through the Golgi complex

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38
Q

after the golgi, what happens to the prohormone

A

secretory vesicles bud off the golgi containing prohormone and enzymes

the enzymes cut the prohormone in active peptides (hormone)

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39
Q

how are peptide hormones secreted

A

vesicles fuses with cell membrane which releases the hormone into the blood

40
Q

where do steroid hormones derive from

A

cholesterol

41
Q

Are steroid hormones water soluble or lipid soluble

A

lipid soluble

42
Q

How do they enter the cell

A

via diffusion

43
Q

What is the half-life of steroids

A

usually hours

they have long half-lives

44
Q

Why do steroid hormones typically have long half-lives

A

bc they bind to plasma protein (Albumin) –> leads to ‘reserve pool’

steroids attached to proteins are NOT CLEARED from the blood readily

45
Q

Steroid receptors bind to which receptor

A

intracellular receptor

46
Q

What do steroid hormones act on once inside the nucleus

A

Chromatin (as TF) ; regulating gene expression

47
Q

steroid hormone lead to delayed, genomic response; true or false

A

TRUE

48
Q

how are steroid hormones usually secreted as

A

pre-prohormone, which have to be cleaved to an active hormone

49
Q

Can steroid hormones be stored in vesicles, why?

A

no they can’t bc they are lipophilic so they would seep out
therefore
made as needed

50
Q

where are steroid hormones made

A

adrenal cortex, gonads, placenta

51
Q

What two hormones classes are Tyr based

A

Thyroid and Catecholamines

52
Q

What hormones are made in the gonads

A

estradiol and other sex hormones

53
Q

what are the some thyroid hormone properties

A

long half-life

nuclear hormones –> act on chromatin

54
Q

What two hormones are Tyr based

A

Thyroid and Catecholamines

55
Q

what hormone is Trp based

A

Melatonin

56
Q

what are the some thyroid hormone properties

A

long half-life

nuclear hormones –> act on chromatin

57
Q

name 2 thyroid hormones

A

Thyroxine (T4)

Triiodothyronine (T3)

58
Q

name 3 Catecholamines

A

dopamine, NE, Epi

59
Q

what are the some Catecholamine properties

A

neurohormones
short half life
acts on cell surface receptors

60
Q

what is short neg feedback

A

the ant. pituitary hormone feeds back on the hypothalamus to inhibit secretion of hypothalamic-releasing hormone
e.g: GH inhibits GHRH

61
Q

what is long neg feedback

A

from the gland the hormone feeds back all the way to the hypothalamic-pit axis
e.g: insulin-like growth factor 1 (IGF-1) is stimulated to be released by GH. IGF-1, in turn, inhibits GHRH and GH

62
Q

what is ultrashort neg feedback

A

hypothalamic hormone inhibits its own secretion

e.g: GHRH inhibits GHRH secretion

63
Q

what is short neg feedback

A

the ant. pituitary hormone feeds back on the hypothalamus to inhibit secretion of hypothalamic-releasing hormone

64
Q

what is long neg feedback

A

from the gland the hormone feeds back all the way to the hypothalamic-pit axis

65
Q

what does positive feedback do

A

product stimulated by hormone release –> eventually cause an increase in hormone release

enhance stimulus
culminates in events

66
Q

Give an example of positive feedback

A

oxytocin during labor

culminates in childbirth

67
Q

Give examples of negative feedback

A

EPO, ANP, aldosterone, ADH/AVP, insulin, leptin

68
Q

What is regulated in peptide hormones

A

BOTH synthesis and release

69
Q

Are steroid hormone synthesis regulated? release?

A

yes synthesis is regulated

no release isn’t bc no storage of steroid hormone

70
Q

What is regulated in amino acid hormones

A

only synthesis

( She put that in her slide, but catecholamines are always put into vesicles and then released upon proper stimulus, not entirely sure if she made a mistake or not).

71
Q

the intended response element will inhibit hormone release, is what type of feedback mech?

A

simple

72
Q

Example of simple feedback

A

glucagon is released in response of low blood sugar. The release then stimulates an increase in blood sugar. Then the increased sugar level causes inhibition of glucagon release

73
Q

what are the major signaling pathways

A
  1. intracellular receptors
  2. jak/stat
  3. GPCR
  4. PI-3 Kinase pathway
  5. RAS pathway
74
Q

What are the properties of intracellular receptors

A

they are inside the cell and have hydrophobic ligands

they act in the nucleus by binding to DNA –> regulating genes

have delayed, genomic response

75
Q

name some hydrophobic ligands

A

Vit D3, cortisol, aldosterone, estrogen

76
Q

jak/stat is a membrane spanning receptor; true or false

A

TRUE

77
Q

which ligands bind to jak/stat

A

prolactin, GH

78
Q

Does STAT activate JAK

A

NOPE!

JAK activates STAT

79
Q

what does STAT do

A

translocates to the nucleus after being activated by JAK and regulates gene expression

80
Q

STAT

A

Signal Transducer and Activator of Transcription

81
Q

JAK

A

Janus Kinase

82
Q

Are GPCR a membrance spanning receptor

A

yes, they bind to ligands at the cell membrane

83
Q

What 3 variants do GPCR activate

A

Gs, Gq, Gi

84
Q

How does Gs work

A

activate adenlyl cyclase –> producing cAMP –>activates PKA –> phosphorylate effector molecules either inhibiting it or activating it

85
Q

what hormones works on Gs

A

Epinephrine (among other, ADH does as well for V2 receptors)

86
Q

Gs has only cellular effects; TRUE or FALSE

A

FALSE

they have both cellular and genomic effects (through CREB)

87
Q

What does Gi do

A

inhibits Gs

88
Q

What does Gq do

A

activates PLC –> PLC will cleave membrane lipids to DAG and IP3 –> leads to an increase in Ca2+ –> activates PKC –> phosphorylate effector molecules

89
Q

Gq only has genomic effects; TRUE or FALSE

A

FALSE, sucka

they have both cellular and genomic effects (through CREB)

90
Q

How does PI-3 kinase work

A

tyrosine kinase (TK) activates PI3 –> activates PKB

91
Q

what kind of effect does PKB have

A

genomic effect

92
Q

what hormone binds to PI-3 kinase

A

insulin

93
Q

How does RAS pathway work

A

TK activates RAF –> activates MEK –> activates ERK –> ERK translocates to the nucleus and has genomic effects

94
Q

What disorder is associated with hyposecretion

A

DM1

95
Q

Cushings is associated with…

A

Hypersecretion (too much cortisol)

96
Q

what disorder is associated with abnl tissue respsonse

A

DM2