Molecular Mechanisms of Signal Transduction

Question 1

What does Radioimmunoassay (RIA) allow detection of?

Answer 1

Tiny quantities of hormones in the blood stream

It is landmark technique for endocrinology

Question 2

7 Major Endocrine Glands

Answer 2

Hypothalmus
Pituitary
Thyroid
Kidneys
Ovaries/Testes
Adrenals
Pancreas

Question 3

What does the Anterior Piuitary secrete?

Answer 3

Tropic Hormones including
ACTH
Thyrotropin
FSH
LH

Question 4

What does the hypothalamus secrete?

Answer 4

Releasing factors that target the pituitary gland

Question 5

What does the posterior pituitary secrete?

Answer 5

Oxytocin and Vasopressin (ADH)

Question 6

What else can the CNS stimulate other than the Hypothalmus?

Answer 6

The adrenal medulla which secretes epinephrine

Question 7

What does changes in blood glucose do to the body?

Answer 7

It’s stimulates the pancreas which will either secrete Insulin or Glucagon

Question 8

What are the 4 main types of Ligands?

Answer 8

Eicosanoids
Steroids
Amines
Peptides

Question 9

What are some examples of protein hormones?

Answer 9

Hypothalmic hormones
Pituitary hormones
Pancreatic Hormones
Leptin
Renin
ANF

Question 10

What are oxytocin and vasopressin?

Answer 10

Nona peptides which differ at only 2 amino acid residues

Question 11

How do oxytocin and vasopressin reach their target tissues?

Answer 11

Each is secreted into general circulation and transported directly

Question 12

What does ADH deficiency result in?

Answer 12

Diabetes insipidus

Question 13

What 3 protein hormones are secreted by the pancreas and what cells are the produced from?

Answer 13

They are produced in the islets of langerhans:
alpha cells: glucagon
beta cells: insulin
gamma cells: somatostatin

Question 14

What signals hormone release in the pancreas?

Answer 14

[Blood Glucose]

Question 15

Where are Epinephrine and Norepinephrine derived from and produced?

Answer 15

They are amine hormones derived from tyrosine and produced in the adrenal medulla

Question 16

What are the thyroid amine hormones and how do they behave?

Answer 16

T3 and T4 are hormones that behave like steroids to regulate BMR

Question 17

What do the gonads release?

Answer 17

They release androgens and estrogens which are sex steroids

Question 18

What do sex steroids target and what is their action?

Answer 18

They target reproductive organs controlling gene expression to regulate sexual development and behavior

Question 19

What kind of hormones are adrenocortical hormones?

Answer 19

Steroid hormones

Question 20

What does the adrenal cortex release?

Answer 20

Corticosteroids:
Glucocorticoids - carb metabolism
Mineralocorticoids - blood electrolytes

Question 21

What are the three types of Eicosanoids/Paracrine Hormones?

Answer 21

Prostaglandins
Leukotrienes
Thromboxanes

Question 22

What happens when the ligand binds to its receptor?

Answer 22

It initiates a series of events that amplifies the signal

Question 23

What are the two possible ultimate goals of the ligand binding to the receptor?

Answer 23

1) activate kinases to alter activity of existing proteins
or
2) activate transcription factors to alter gene expression

Question 24

Is activating kinases a rapid or slow and transient or prolonged response?

Answer 24

A very rapid & transient response

Question 25

Is activating transcription factors a rapid or slow and transient or prolonged response?

Answer 25

A slower & prolonged response

Question 26

Signals are…

Answer 26

Specific
Amplified
Desensitized
Integrated
Transient

Question 27

What does specificity mean?

Answer 27

A signal molecule only binds to one site that no other signals fit into

Question 28

What does amplification mean?

Answer 28

When the enzymes activate, the number of affected molecules increases geometrically in an enzyme cascade

Question 29

What does desensitization mean?

Answer 29

Receptor activation triggers a feedback circuit that shuts off the receptor or removes it from the cells surface

Question 30

What does repeated signaling lead too?

Answer 30

Desensitization

Question 31

What does integration mean?

Answer 31

Two signals of opposite effects gives a summed response from both receptors

Question 32

What does transient mean?

Answer 32

Signals are self-limiting

Many transient systems are disrupted in disease.

Question 33

What are the 6 major classes of hormone receptors?

Answer 33

Gated ion channels
Receptor enzymes
Serpentines
Adhesion
Steroid
Orphan

Question 34

What are the major classes of G proteins?

Answer 34

Gs: stimulates adenylate cyclase
Gi: inhibits adenylate cyclase
Gq: stimulates phosphlipase c

Question 35

What does cell response depend on when it comes to G proteins?

Answer 35

The type of G protein coupled to the hormone receptor and available intracellular target for phosphorylation by activated protein kinase

Question 36

What toxins interfere with G proteins?

Answer 36

Cholera Toxin

Pertussis Toxin

Question 37

What are transcription factors?

Answer 37

Proteins that bind to specific DNA sequences within gene promoter regions and enhance or repress transcription of that gene.

Question 38

What are some examples of Transcription factors

Answer 38

NFB
Myc
STAT
p53
Steroid hormone receptors

Question 39

What are steroid hormones carried by to reach their target tissues?

Answer 39

They are carrie by specific globulins in the blood

Question 40

Do steroid hormones pass readily through the plasma membrane?

Answer 40

Yes

Question 41

What do steroid hormones bind to?

Answer 41

Cytosolic and nuclear receptors

Question 42

What are HREs?

Answer 42

Hormone response elements

Question 43

What does the steroid/receptor complex interact with?

Answer 43

Specific DNA elements in genome