Growth Hormone

Question 1

GH secretion

Answer 1

Secreted by somatotrophs

Most abundant hormone of adult anterior pituitary

Question 2

GH release

Answer 2

Stimulated by sleep, exercise, stress

Inhibited by food ingestion

Question 3

GH Hypothalamic influence

Answer 3

GHRH (positive)

Somatostatin (negative)

Question 4

Random GH measurements

Answer 4

Little value
Pulsatile release
Short half life

Question 5

GH stimulates production of

Answer 5

Insulin like growth factor 1 (IGF-1)
–> produced in many tissues, mainly liver
GH has both direct effects and IGF1 mediated effects

Question 6

GH effects

Answer 6

Increase basal metabolism
Promotes growth of long bones
Stimulates muscle growth and protein synthesis
Both GH and IGD1 affect glucose homeostasis

Question 7

GH on glucose homeostasis

Answer 7

Increases hepatic glycogenolysis
Increases lipolysis
Reduces peripheral glucose intake

Question 8

IGF1 on glucose homeostasis

Answer 8

Similar to insulin
Stimulate peripheral glucose uptake
Stimulate glycogen synthesis

Question 9

GH excess in childhood

Answer 9

Gigantism

Question 10

GH excess in adulthood

Answer 10

Acromegaly

Question 11

Acromegaly signs and symptoms

Answer 11

MSK
Cardiovascular
Metabolic
Skin
General
Local tumour effects

Question 12

Acromegaly symptoms- MSK

Answer 12

Protruding mandible (prognathia)
Large tongue (macroglossia)
Enlarged forehead (frontal bossing)
Large hands and feet
Carpal tunnel syndrome
OA from abnormal joint loading

Question 13

Acromegaly symptoms- CV

Answer 13

Dilated cardiomyopathy–> leading cause mortality in acromegaly patients
Cardiac failure
Hypertension

Question 14

Acromegaly symptoms- metabolic

Answer 14

Impaired glucose tolerance

Potentially secondary diabetes

Question 15

Acromegaly symptoms

Answer 15

Excessive sweating

Thickened, greasy skin

Question 16

Acromegaly symptoms- General

Answer 16

Headaches

Tiredness (often v. debilitating)

Question 17

Acromegaly symptoms- local tumour effects

Answer 17

Optic chiasm and visual field defects
Cavernous sinus (CN III, IV and VI)

Question 18

Acromegaly Investigations

Answer 18

Oral glucose tolerance test
MRI pituitary
Insulin tolerance test

Question 19

Acromegaly- OGTT

Answer 19

Growth hormone fluctuates so much hard to test on its own
GH usually suppressed by eating
Unsuppressed GH levels after 75 glucose implies GH excess

Question 20

Acromegaly- insulin tolerance test

Answer 20

GH released in response to hyoglycaemia

Question 21

Acromegaly- management

Answer 21

Trans-sphenoidal surgery may be curative- 1st line if appropriate
Medical
External beam radiotherapy if medical management not effective

Question 22

Acromegaly- medical managment

Answer 22

Somatostatin analogue- Octreotide
Dopamine antagonists (e.g. bromocriptine) may be of benefit, especially when tumour co-secreting prolactin
GH receptor blocker (Pegvisomant)

Question 23

Dopamine antagonist

Answer 23

Bromocriptine

Question 24

Somatostatin analogue

Answer 24

Octreotide

Question 25

GH receptor blocker

Answer 25

Pegvisomant

Question 26

Bromocriptine

Answer 26

Dopamine antagonist

Question 27

Octreotide

Answer 27

Somatostatin analogue

Question 28

Pegvisomant

Answer 28

GH receptor blocker

Question 29

Acromegaly management

Answer 29

Link between acromegaly + development of colonic polyps –> increased risk bowel cancer
Patients should have colonoscopy at diagnosis
Surveillance colonoscopy for those with GH excess