Molecular Mechanisms of Signal Transduction Flashcards Preview

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Flashcards in Molecular Mechanisms of Signal Transduction Deck (43):
1

What does Radioimmunoassay (RIA) allow detection of?

Tiny quantities of hormones in the blood stream
It is landmark technique for endocrinology

2

7 Major Endocrine Glands

Hypothalmus
Pituitary
Thyroid
Kidneys
Ovaries/Testes
Adrenals
Pancreas

3

What does the Anterior Piuitary secrete?

Tropic Hormones including
ACTH
Thyrotropin
FSH
LH

4

What does the hypothalamus secrete?

Releasing factors that target the pituitary gland

5

What does the posterior pituitary secrete?

Oxytocin and Vasopressin (ADH)

6

What else can the CNS stimulate other than the Hypothalmus?

The adrenal medulla which secretes epinephrine

7

What does changes in blood glucose do to the body?

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

8

What are the 4 main types of Ligands?

Eicosanoids
Steroids
Amines
Peptides

9

What are some examples of protein hormones?

Hypothalmic hormones
Pituitary hormones
Pancreatic Hormones
Leptin
Renin
ANF

10

What are oxytocin and vasopressin?

Nona peptides which differ at only 2 amino acid residues

11

How do oxytocin and vasopressin reach their target tissues?

Each is secreted into general circulation and transported directly

12

What does ADH deficiency result in?

Diabetes insipidus

13

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

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

14

What signals hormone release in the pancreas?

[Blood Glucose]

15

Where are Epinephrine and Norepinephrine derived from and produced?

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

16

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

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

17

What do the gonads release?

They release androgens and estrogens which are sex steroids

18

What do sex steroids target and what is their action?

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

19

What kind of hormones are adrenocortical hormones?

Steroid hormones

20

What does the adrenal cortex release?

Corticosteroids:
Glucocorticoids - carb metabolism
Mineralocorticoids - blood electrolytes

21

What are the three types of Eicosanoids/Paracrine Hormones?

Prostaglandins
Leukotrienes
Thromboxanes

22

What happens when the ligand binds to its receptor?

It initiates a series of events that amplifies the signal

23

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

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

24

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

A very rapid & transient response

25

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

A slower & prolonged response

26

Signals are...

Specific
Amplified
Desensitized
Integrated
Transient

27

What does specificity mean?

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

28

What does amplification mean?

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

29

What does desensitization mean?

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

30

What does repeated signaling lead too?

Desensitization

31

What does integration mean?

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

32

What does transient mean?

Signals are self-limiting

Many transient systems are disrupted in disease.

33

What are the 6 major classes of hormone receptors?

Gated ion channels
Receptor enzymes
Serpentines
Adhesion
Steroid
Orphan

34

What are the major classes of G proteins?

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

35

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

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

36

What toxins interfere with G proteins?

Cholera Toxin
Pertussis Toxin

37

What are transcription factors?

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

38

What are some examples of Transcription factors

NFB
Myc
STAT
p53
Steroid hormone receptors

39

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

They are carrie by specific globulins in the blood

40

Do steroid hormones pass readily through the plasma membrane?

Yes

41

What do steroid hormones bind to?

Cytosolic and nuclear receptors

42

What are HREs?

Hormone response elements

43

What does the steroid/receptor complex interact with?

Specific DNA elements in genome