Growth Hormone (GH) Flashcards
What is the major regulatory hormone of growth?
Growth hormone
What is another name for the growth hormone?
Somatotropin (ST)
What category of hormone is growth hormone in?
Protein hormone
Where does the production of the growth hormone take place?
Anterior pituitary
What are the direct target organ/s for the growth hormone?
Liver (mainly), and other organs
What are the indirect target organ/s for the growth hormone?
Bone, muscle, fat, others - through IGF-1
What kind of effect does growth hormone have?
Anabolic
Growth hormone is secreted during _________. What time period is it most secreted?
- sleep
- between 12am-2am
What are the functions of the growth hormone?
How does the growth hormone control these processes?
- Increases growth of most tissues
- Mobilizes energy required for growth
- With direct and indirect effects
What are the direct effects of the growth hormone?
Mediated through growth hormone receptors
What are the indirect effects of the growth hormone?
Modulated through the release of other hormones or growth factors.
What is the category of hormone, production, direct target organs, and effect of the Insulin-like Growth Factor-1 (IGF-1)?
Category: Protein hormone
Production: LIVER, skeletal muscle, kidney, adipose, bone
Direct target organs: Liver, skeletal muscle, kidney, adipose, bone
Effect: Anabolic
What does IGF-1 bind to?
IGF binding proteins
True or False: Different versions of IGF-1 have the same levels of activity
FALSE - Different versions of IGF-1 have different levels of activity
that’s why there’s a difference between miniature and standard size
Tell me the specific actions GH and IGF-1 do for bone. Which are indirect or direct actions?
GH: (direct actions)
- promotes chondrocyte proliferation
- promotes longitudinal bone growth
IGF-1: (indirect actions)
- promotes chondrocyte proliferation
- promotes osteoblast activity
- promotes longitudinal bone growth
- promotes periosteal growth
- promotes bone mass
Largely indirect actions
Tell me the specific actions GH and IGF-1 do for muscle. Are these direct or indirect actions?
GH: (direct actions)
- promotes protein synthesis
- inhibits protein degradation
- promotes amino acid absorption
IGF-1: (indirect actions)
- promotes glucose absorption
- promotes amino acid absorption
- promotes protein synthesis
Tell me the specific actions GH and IGF-1 do for adipose. Which are direct or indirect actions?
GH:
- promotes lipolysis (direct)
- inhibits insulin stimulation of glucose uptake (indirect)
- promotes catecholamine-stimulated lipolysis (indirect)
No IGF-1
Describe four strategies that enhance livestock growth and performance.
1) The growth hormone is administered as an injection frequently and systemically. This strategy enhances livestock growth and performance by increasing body weight, improving feed conversion, decreasing feed intake, and having carcasses contain more muscle and less fat.
2) Administration of the Growth Hormone-Releasing Hormone (GHRH) is a strategy used to enhance livestock growth and performance. This strategy results in similar composition differences compared with exogenous GH and is administered very frequently, considering that it is a peptide.
3) Immunizing animals against somatostatin is another strategy used to enhance livestock growth and performance. This strategy increases the growth hormone secretion by releasing the suppressive effects of somatostatin, which increases growth.
4) Creating transgenic animals is another strategy used to enhance livestock growth and performance. We can create transgenic animals by inserting an extra copy of the growth hormone gene that can be turned off and on. The overexpression of the growth hormone results in an increased amount of growth in the animal.
