Endocrine

Question 1

List some amines

Answer 1

Catecholamines, serotinin, thyroxine

Question 2

List steroids

Answer 2

Cortisol, aldosterone, androgens, oestrogens, progesterones, vit D

Question 3

List some peptides

Answer 3

Everything else - made of amino-acids

Question 4

Features of amines/peptides

Answer 4

Short half life (minutes).

Secretion can be pulsatile.

Act on cell surface receptor

Act via secondary messenger often

Question 5

Features of steroids

Answer 5

Longer half life (hours)

Act on intracellular receptor

Act on DNA to alter gene expression

Question 6

Which peptide/amine hormones are transmitted via cAMP?

Answer 6

Adrenaline

Pituitary hormones (except GH, PRL)

Glucagon

Somatostatin

e.g assume all except insulin or ‘growth’

Question 7

Which peptide/amine hormones are transmitted via rise in intracellular calcium levels?

Answer 7

GnRH
TRH

Adrenaline

Question 8

Which peptide/amine hormones are transmitted via receptor tyrosine kinases?

Answer 8

Insulin
GH, PRL
Growth factors - IGF-1 EGF

Question 9

How to hormone receptors linked to cAMP work?

Answer 9

Interact with adenylate cyclase which generates cAMP.

All but somatostatin increase cAMP intracellularly by acting on Gs (stimulatory G protein)

Somatostatin reduced cAMP levels and acts via inhibitory g-protein Gi

Question 10

Which diseases are associated with mutations in Gs?

Answer 10

Acromegaly
McCune-Albright
Pseudohypoparathyroidism

Question 11

Role of intracellular ca

Answer 11

Some hormones release calcium as secondary messenger.

Receptors activate different G proteins > activate phospholipase C >release of IP3 from phospholipids >IP-3 which triggers calcium release > Calcium affects cell metabolism by binding to calmodulin

Question 12

How do receptor tyrosine kinase work?

Answer 12

No secondary messengers (insulin, GF, PRL)

Receptors can act as enzymes that phosphorylate other proteins when hormone is bound -> gene transcription in nucleus is modulated.

Question 13

Which hormones can diffuse directly through cell membrane?

Answer 13

Vit D
Steroids
Thyroxine

Bind to receptors in cytoplasm > hormone-receptor complex migrates to nucleus > alters gene transcription

Question 14

Hormone response in illness/stress?

Answer 14

TSH, T3/4, LH, FSH, testosterone, oestrogen, insulin (starvation) all FALL

GH, ACTH, Glucocorticoids, adrenaline, glucagon, PRL RISE

Question 15

Hormones in starvation?

Answer 15

All fall except glucagon

Question 16

Hormones in anorexia nervosa (starvation & stress)

Answer 16

Glucagon, GH, glucocorticoids rise

All others fall

Question 17

Hormone changes in obesity

Answer 17

Hyperinsulinaemia
Increased androgens in women
Reduced GH
Androgens converted to oestrogens
Bad lipid changes (lowHDL, high LDL, triglycerides)

Question 18

What is leptin?

Answer 18

Polypeptide released from fat cells > acts on receptors in hypothalamus to reduce appetite

Question 19

Role of grehlin

Answer 19

Released from stomach & triggers hunger (fall after gastric bypass)

Question 20

Role of peptide YY

Answer 20

Released from small and large bowel after meals to reduce appetite (e.g fullness)

Question 21

Role of GLP-1

Answer 21

Released from intestine after meals > stimulates insulin secretion

Question 22

Hormones in hypothalamus that affect appetite?

Answer 22

Neuropeptide Y and agouti-related peptide increase appetite

alpha-MSH reduces appetite

Question 23

Hormone changes in pregnancy

Answer 23

Gradual increase in prolactin in prep for lactation. Big surge after birth the drops to normal within 2 weeks.

Rise in T3/T4 in 1st trimester

Question 24

What are suppression tests used for?

Answer 24

To test for hormone excess

Question 25

What are stimulation tests used for?

Answer 25

Test for hormone deficiency

Question 26

Causes of raised prolactin?

Answer 26

Prolactinoma Typical antipsychotics Metoclopramide Pregnancy Nipple stimulation Oestrogens PCOS Stress Negatively controlled by dopamine (reduced dopamine stumates increase in prolactin)

Question 27

Example of dopamine agonist

Answer 27

Bromocriptine (reduces prolactin)

Question 28

What is the role of 11-beta hydroxysteroid dehydrogenase

Answer 28

Alters cortisol to prevent it from binding to aldosterone (mineraloscortcoid) receptors Mutations in the enzyme or inhibition by liquorice causes apparent aldosterone excess as cortisol can then bind

Question 29

Half life of T4 and T3

Answer 29

7 days and 1 day respectively

Question 30

Raised T3 in sick patient

Answer 30

Thyrotoxicosis Everything should be low (TSH, T3, T4)

Question 31

Role of ANP

Answer 31

Synthesised by myocytes in RA/RV and released due to hypervolaemia (stretch of RA/RV) Causes natriuresis (urinary excretion of sodium) to lower circulating volume

Question 32

Commonest thyroid cancer?

Answer 32

Papillary (70%) Young people, slow growing

Question 33

Cells affected in medullary thyroid cancer?

Answer 33

c-cells (calcitonin) Serum calcitonin is a tumour marker Associated with MEN 2

Question 34

Follicular thyroid cancer?

Answer 34

F>M Asymmetric thyroid nodule

Question 35

Anaplastic thyroid cancer?

Answer 35

Aggressive Tends to affect elderly Thyroid mass Can cause pressure symptoms/locally invasive

Question 36

HLA antigen associated with narcolepsy?

Answer 36

HLA DR2

Question 37

Gitelmans syndrome Presentation Cause

Answer 37

Normotensive Hypokalaemia Hypocalciuria Hypomag Metabolic alkalosis

Question 38

HPV 11

Answer 38

Genital warts

Question 39

HPV 16,18

Answer 39

Cervical cancer

Question 40

Chromosome abnormality in klinefelters

Answer 40

47 XXY