Feedback Loop: Growth Hormone (GH)

Growth Hormone:

 • Liver -> GHR activates JAK-STAT pathway -> Incr IGF1

 • Bone - IGFIR activates osteoblasts and chondrocytes -> Incr ossification

 • Muscle -> GHR activates JAK-STAT pathway -> Incr gene expression/protein synthesis of IGF1R -> Activation of AKT pathway -> Incr cell growth & survival

 • Adipose Tissue -> GHR activates lipolysis

Signs/Symptoms:

 • GH deficiency: 

    - Short stature

    - Decr strength

    - Incr fat mass, abn lipid 

 • GH excess: 

    - Giantism or acromegaly, widening of hands/feet

    - Soft tissue expansion (e.g. carpal tunnel, OSA, Incr skin thickness)

    - metabolic abn



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