Energy Balance Flashcards
What are the key hormonal systems involved in humans/animals?
- GH (insulin-like growth factor-1 = IGF-1 axis)
- thyroid hormones
- sex hormones
- androgens
- estrogens
- insulin
What other hormones have powerful modifying effect?
- cortisol
- glucocorticoids
- leptin
- progesterone
What study models can be used to study growth?
- deficiency syndromes (GH/iodine deficiency)
- over-production tumours (pituitary tumours)
- pharmacological stimulation
- nutritional interactions (under/over-feeding studies)
What is leptin from adipose tissue’s effect on?
appetite and growth
When the body cannot produce leptin, what happens?
obese
What is myostatin?
negative regulator of skeletal muscle growth
- its deletion/inhibition causes extreme muscular development in animals/humans
Why is there a need for energy balance?
for net accretion of tissues to take place and growth to occur in muscle/lean/organ/adipose tissues and bone + fat mass
What are the body composition compartments?
- body fat
- skeletal muscle mass
- organs
- water
- bones
What is body fat made up principally of?
adipose tissue made of lipids
What are organs and skeletal muscle made up of?
lean tissue made up of protein and water predominantly
What is bone tissue made up of?
minerals and some protein
What is protein turnover?
takes place everyday, continuous breakdown and renewal of protein
What must be so, for NET protein synthesis to occur?
synthesis MUST be greater than breakdown
Name the anabolic hormones having the positive effect on net protein synthesis in muscle:
- GH-IGF
- androgens
- insulin
Name the catabolic hormones having the negative effect on net protein synthesis in muscle:
- cortisol
- glucocorticoids
- proinflammatory cytokines
Name the hormones that have modulatory effects on growth and protein turnover:
- catecholamines
- thyroid hormone (major impact on fetal growth)
- estrogens
- progesterones
- leptin
- ghrelin
Name the particular amino acids that are essential for protein synthesis to occur:
- essential aa
- branched chain aa (leucine)