Growth Hormone Flashcards
GH secretion
Secreted by somatotrophs
Most abundant hormone of adult anterior pituitary
GH release
Stimulated by sleep, exercise, stress
Inhibited by food ingestion
GH Hypothalamic influence
GHRH (positive)
Somatostatin (negative)
Random GH measurements
Little value
Pulsatile release
Short half life
GH stimulates production of
Insulin like growth factor 1 (IGF-1)
–> produced in many tissues, mainly liver
GH has both direct effects and IGF1 mediated effects
GH effects
Increase basal metabolism
Promotes growth of long bones
Stimulates muscle growth and protein synthesis
Both GH and IGD1 affect glucose homeostasis
GH on glucose homeostasis
Increases hepatic glycogenolysis
Increases lipolysis
Reduces peripheral glucose intake
IGF1 on glucose homeostasis
Similar to insulin
Stimulate peripheral glucose uptake
Stimulate glycogen synthesis
GH excess in childhood
Gigantism
GH excess in adulthood
Acromegaly
Acromegaly signs and symptoms
MSK Cardiovascular Metabolic Skin General Local tumour effects
Acromegaly symptoms- MSK
Protruding mandible (prognathia) Large tongue (macroglossia) Enlarged forehead (frontal bossing) Large hands and feet Carpal tunnel syndrome OA from abnormal joint loading
Acromegaly symptoms- CV
Dilated cardiomyopathy–> leading cause mortality in acromegaly patients
Cardiac failure
Hypertension
Acromegaly symptoms- metabolic
Impaired glucose tolerance
Potentially secondary diabetes
Acromegaly symptoms
Excessive sweating
Thickened, greasy skin