Wednesday, July 17, 2024
No menu items!
HomeEndocrine PhysiologyGrowth hormone effects on carbohydrate, fat, and protein metabolism

Growth hormone effects on carbohydrate, fat, and protein metabolism

  • Direct effect by the growth hormone
  • Indirect effect- through insulin-like growth factor-I (IGF-I) or somatomedins C. It is released predominantly from the liver in response to GH. The overall functions of growth hormones are summarized in the picture below.
Actions mediated by growth hormones

Metabolic effect

On carbohydrate metabolism: hyperglycemic effect

  • Increase gluconeogenesis by the liver
  • Decrease glucose uptake by skeletal muscle & fat
  • Induced insulin resistance
  • Ketogenic- it increases circulating FFA and increases ketone bodies (acetoacetate,  hydroxybutyrate, and acetone)

Anabolic effect on protein metabolism

  • Increase amino acid  transport through the cell membrane
  • Increase DNA transcription to form RNA
  • Increase RNA translation 
  • Protein sparer

Catabolic effect on fat metabolism

  • Growth hormone enhances fat utilization by stimulating triglyceride breakdown ( blood FFA).
  • Fat is used for energy in preference to carbohydrates & proteins.

Hyposecretory state of growth hormone

Dwarfism

  • Short stature, due to GHRH, GH, IGF-I deficiency 
  • Laron Dwarfism (GH insensitivity): Plasma concentration of GH normal or elevated but GH receptors are unresponsiveness.
  • African Pigmies: normal plasma GH but the congenital inability to produce normal plasma somatomedin c (IGF-1).
  • Psychosocial dwarfism (Kaspar Hauser syndrome): chronic abuse and neglect cause dwarfism in children.

Hypersecretory state of growth hormone

Gigantism:

  • Caused by the tumor of the anterior pituitary gland before puberty.
  • Epiphyseal growth plates open state.
  • This leads to excessive growth of long bones

Acromegaly

  • If the tumor of the anterior pituitary gland occurs after puberty
  • after the epiphyses of the long bones have fused with shafts
  • soft tissue continues to grow and the bones grow in thickness.

Stimuli that affect GH secretion:

  • Hypoglycemia, fasting    
  • starvation with severe protein deficiency
  • Increase circulating amino acid(protein meal)
  • Decrease FFA
  • Stress (exercise, trauma, excitement)
RELATED ARTICLES

LEAVE A REPLY

Please enter your comment!
Please enter your name here

- Advertisment -

Most Popular

Recent Comments