Basics of endocrine

Question 1

What are the different types of hormone receptors?

Answer 1

GPCR
RTK
Nuclear

Question 2

What is the structure of GPCR?

Answer 2

7 transmembrane domain

Question 3

What are the major intracellular signalling molecues?

Answer 3

cAMP

IP3

Question 4

What are the effectors of GCRP receptors?

Answer 4

Adenylyl cyclase
Phospholipase C
GIRk
PI3 kinase

Question 5

What hormones are released by the anterior pituitary?

Answer 5

GH
LH/FSH
ACTH
TSH
PRL

Question 6

What hormones are released from the posterior pituitary?

Answer 6

ADH

Oxytocin

Question 7

What needs to be taken into consideration when measuring hormones?

Answer 7

Pattern of secretion
Presence of carrier proteins
Intefering agents
Stability of hormone (consisder half life) 
Absolute concentrations

Question 8

What hormones commonly require evaluation?

Answer 8

Thyroid
Steroid - cortisol
GH evaluation 
Reproductive and sex hormones
Prolactin 
Calcium and PTH 
Renin/ aldosterone
Catecholamines
Gut hormones

Question 9

Raised TSH suggests what?

Answer 9

Hypothyroid

Question 10

Supressed TSH sugests what?

Answer 10

Hyperthyroid

Question 11

When might TSH not be a reliable marker of thyroid status?

Answer 11

In secondary thyroid disease where the issue arises from the pituitary and therefore the levels of TSH will be off

Question 12

How is pituitary function assessed?

Answer 12

9am cortiol
TSH, fT4/3
Prolactin
IGF1 (GH)
LH, FSH, E2 (females)/ testosterone (males) 
U&E, plasma/urine osmolality

Question 13

What rhythm does cortisol secretion follow?

Answer 13

Circadian rhythm

Diurinal

Question 14

When are cortisol levels at their highest and lowest?

Answer 14

Highest at 9am

Lowest at midnight

Question 15

What axis will 9am cortisol give an indication of?

Answer 15

HPA axis - ACTH release

Question 16

How is growth hormone measured?

Answer 16

IGF-1 to indicate GH hypersecretion

Formal GH axis requires dynamic testing

Question 17

What pattern will female sex hormones show?

Answer 17

Menstrual cycle

Question 18

When should testosterone be measured?

Answer 18

9am

Question 19

What is prolactin secreted by?

Answer 19

Lactotroph cells of the anterior pituitary

Question 20

What inhibits the production of prolactin?

Answer 20

Dopamine

Question 21

What mediates the effects of prolactin?

Answer 21

Prolactin receptor (PRLR)

Question 22

What will act on the hypothalamus in the regulation of thirst and water?

Answer 22

Hyperosmolarity
Angiotensin 2
Sympathetic stimualtion
Decreased atrial firing

Question 23

What is the action of vasopressin 1?

Answer 23

Constriction of blood vessels
Increased systemic vascualr resistance
Increased arterial pressure

Question 24

What is the action of vasopressin 2?

Answer 24

Acts on the kidneys to increased fluid reabsorption increasing the blood volume
This increases arterial pressure

Question 25

What is the common precursor of all steroid hormones?

Answer 25

Pregenolone

Question 26

What dynamic test is used for hormone excess?

Answer 26

Suppression test

Question 27

What dynamic test is used for hormone deficiency?

Answer 27

Stimulation test

Question 28

What condition is characterised by primary cortisol deficiency?

Answer 28

Addisons disease

Question 29

What is cushings syndrome?

Answer 29

Cortisol excess

Question 30

What can cause cushings syndrome?

Answer 30

Pituitary origin Adrenal origin Ectopic ACTH Exogenous steroids

Question 31

What is synacthen tests?

Answer 31

A stimulation test - used for addisons

Question 32

When is the dexamethasone suppression test used?

Answer 32

In cushings syndrome

Question 33

What are the signs and symptoms of cushings syndrome?

Answer 33

``` Cushoingoid faces Acne Hirsutism Abdominal striae Obesity Interscapular and suprascapular fat pads Proximal myopathy Osteoporosis Hypertension Impaired glucose tolerance ```

Question 34

What is cushings disease?

Answer 34

Tumour arising from the corticotroph cells of the anterior pititary

Question 35

Where does cushings DISEASE originate?

Answer 35

Pituitary

Question 36

Where does ACTH independent cushings originate?

Answer 36

Adrenal adenoma/carcinoma

Question 37

What happens to the adrenal gland in ACTH-independent cushings?

Answer 37

Bilateral macronodular adrenal hyperplasia

Question 38

What causes ectopic ACTH?

Answer 38

Malignancy - commonly lung cancer

Question 39

What causes exogenous cushings?

Answer 39

Oral, inhaled, topical, injectable steroid use

Question 40

What will hapen to the ACTH levels in ACTH-independent cushings?

Answer 40

Levels should be undetectable

Question 41

What are the screening tests for cushings?

Answer 41

1mg overnight dexamethasone suppression test 24 hour urinary free cortisol Midnight cortisol

Question 42

What is the formal diagnostic test for cushings??

Answer 42

Low dose dexamethasone supression test - failure to suppress = cushings

Question 43

What type of cushings will a low ACTH show?

Answer 43

Adrenal origin

Question 44

What type of cushings will a raised ACTH show?

Answer 44

Need to disinguish between cushings disease (pituitary origin) and ectopic ACTH

Question 45

What is the formal diagnostic test for cushings disease?

Answer 45

Rise in cortisol and ACTH on CRH (corticortophic releasing hormone) test indicates a pituitary source

Question 46

What is an inferior petosal sinus sampling?

Answer 46

Used to lateralize the tumour prior to surgery