wk 4- Hormones (steroid and peptide)

Question 1

What is the biochemical mechanism responsible for transmitting extracellular signals across the plasma membrane and throughout the cell?

Answer 1

Signal transduction

Question 2

What are examples of signal transduction?

Answer 2

Flux through metabolic pathways
Ion flow through plasma membrane
Cell mobility
Gene expression

Question 3

Water soluble signalling molecules bins to what type of receptors?

Answer 3

Cell surface receptors

Question 4

What receptors do lipophillic dervived from cholesterol bind to?

Answer 4

Intracellular receptors

Question 5

What ligands mediate hormone signals by altering the expression for specific genes?

Answer 5

Cholesterol-derived

Question 6

What are the multiple categories of steroid hormones?

Answer 6

Glucocorticoids
Mineralcorticoids
Androgens
Estrogens

Question 7

Role of glucocorticoids

Answer 7

Regulation of glucose metabolism

Question 8

Role of mineralcoticoids

Answer 8

Salt and water balances

Question 9

Role of androgens

Answer 9

Regulate the development and maintenance of male characteristics in vertebrates (testosterone)

Question 10

Role of estrogens

Answer 10

Development and regulation of female reproductive system (estradiol)

Question 11

What are synthetic steroids

Answer 11

Agonists that mimic the biological response of the hormone

Question 12

Type of steroids that bodybuilders use

Answer 12

Anabolic steroid (builds up muscles)

Question 13

3 categories of hormones

Answer 13

Endocrine (steroids)
Paracrine (growth factor)
Autocrine

Question 14

What type of cells do steroid hormones exit?

Answer 14

Endocrine cells

Question 15

The cell-specific physiological responses controlled by intracellular/nuclear receptors is governed by what 3 parameters?

Answer 15

Cell specific expression of nuclear receptors
Localized bio-availability of ligands
Differential accessibility of target gene DNA sequences in chromatin nuclear receptor binding

Question 16

Briefly describe the general mechanism of nuclear/intracellular receptor signalling

Answer 16

1) Binding of lipophillic first messengers to ligand binding domain
2) Ligand activated nuclear receptors bind directly or indirectly to hormone regulatory elements in DNA - alters transcription rates in chromatin structure

Question 17

How to steroids receptors bind to inverted repeat DNA sequences?

Answer 17

Head-to-head homodimers (in pairs) - increases specificity meaning more contact

Question 18

Where is the glucocorticoid receptor synthesized?

Answer 18

Adrenal gland

Question 19

What term is also used for inverted repeat?

Answer 19

Palindromic

Question 20

What are the 3 different modes of transcriptional regulation of the glucocorticoid-responsive promoters by glucocorticoid receptors?

Answer 20

Simple transactivation
Tethering
Synergism

Question 21

What are simple and composote promoters?

Answer 21

Simple- Simple transactivation and Tethering

Composite- Synergism

Question 22

What is simple transactivation?

Answer 22

The receptor binds directly to the responsive elements

Question 23

What is Tethering?

Answer 23

The receptor binds to a transcriptional factor before binding to the responsive elements

Question 24

What is Synergism?

Answer 24

A combination of the other two. The transcription factor may have an effect of the receptor binding to the responsive element. vice versa

Question 25

How do glucocorticoid recepors regulate anti-inflammatory responses?

Answer 25

By down regulation the expression of pro-inflammatory proteins

Question 26

What is the definition of hormones?

Answer 26

Any substance elaborated by one cell to regulate another cell. May be delivered by autocrine, paracrine or endocrine routes

Question 27

True or false- Most hormones have effects on multiple targets in the body

Answer 27

True

Question 28

What 3 classes are hormones grouped into based on their structure?

Answer 28

Steroid hormones Amine-derived hormones Peptide hormones

Question 29

What hormones are hydrophilic and transported unbound in blood plasma?

Answer 29

Peptide hormones

Question 30

Where are peptide hormones secreted from?

Answer 30

pituitary, parathyroid, heart, stomach, liver, kidneys

Question 31

Where is mature insulin stored?

Answer 31

Secretory vesicles

Question 32

How can different end hormones be made?

Answer 32

By cleaving a common precursor with a different enzyme

Question 33

What are coactivators?

Answer 33

Proteins that acetylate histones

Question 34

Where is the coregulatory protein binding site located?

Answer 34

On the surface of the GR ligand binding domain (hydrophobic pocket)

Question 35

What is the difference between pharmaceutical glucocoticoids than that of physiologic steroids?

Answer 35

They have a higher binding affinity for the glucocoticoid receptor