Growth Hormone (GH)Growth Hormone (GH)Holly FarrisHolly Farris

What Is It?What Is It?

191-amino acid, single chained 191-amino acid, single chained polypeptidepolypeptide

Synthesized, stored, and secreted Synthesized, stored, and secreted by somatotrophic cellsby somatotrophic cells

Anterior Pituitary glandAnterior Pituitary gland

FunctionFunction

Increased height in childhood and adolescents –most Increased height in childhood and adolescents –most known effectknown effect

Increases mineralization of bonesIncreases mineralization of bones

Muscle massMuscle mass

Stimulates growth of internal organs- excluding the brainStimulates growth of internal organs- excluding the brain

Immune systemImmune system

Positive or Negative?Positive or Negative?

NegativeNegative High blood levels of IGF-I leads to decreased High blood levels of IGF-I leads to decreased

secretion of GHsecretion of GH IGF-1 directly suppresses the somatotrophic IGF-1 directly suppresses the somatotrophic

cellscells

HyperHyper

Gigantism- excessive growth, usually in Gigantism- excessive growth, usually in childhood childhood

Most commonMost common Pituitary Tumor - causes headaches, impair Pituitary Tumor - causes headaches, impair

vision by pressure on the optic nervesvision by pressure on the optic nerves

HypoHypo

In children:In children: Growth failure Growth failure Short statureShort stature

In adults:In adults: Increase in fat massIncrease in fat mass Decrease muscle mass, energy and quality of Decrease muscle mass, energy and quality of

lifelife