Endocrine Regulation of Growth ✅ Flashcards
What exerts the major influence on post-natal growth?
Growth hormone
What kind of molecule is growth hormone?
An amino-acid polypeptide
How does growth hormone exist in the circulation?
Bound to a GH-binding protein
What is the GH-binding protein derived form?
The extracellular component of the GH receptor
Where is GH secreted from?
Somatotroph cells
What regulates the secretion of GH?
Dual control of;
- GH releasing hormone
- Somatostatin
Where is GH-releasing hormone and somatostatin secreted from?
The hypothalamus
Why is dual regulation of GH required?
To produce episodic pulses
At what time of day is GH-releasing hormone and somatostatin released?
Mostly at night
What regulates the release of GH-releasing hormone and somatostatin?
Central neurotransmitters
What stimuli do central neurotransmitters causing release of GH-releasing hormone and somatostatin respond to?
- Nutrition
- Sleep
- Exercise
- Stress
Where does GH act?
Liver and a number of other organs
What does GH stimulate in the liver and other organs?
The synthesis of insulin-like growth factors (IGF-1 and IGF-2)
What is the similarity between insulin-like growth factors and insulin?
They share a degree of structural homology with proinsulin, and may exert weak insulin-like effects
How does IGF-1 circulate?
Bound to IGF binding protein (IGFBP-3)
