Major Hormone Flashcards
Includes
Thyroid hormone Insulin Glucagon Epinephrine Cortisol Aldosterone Somatostatin Parathyroid hormone Calcitriol Growth Hormone
What stimulates & inhibits Thyroxine release?
S] Cold Pregnancy & Exercise
I] Glucocorticoids e.g. cortisol & Somatostatin
What does thyroxine do?
Increases:
- Metabolic rate
- Thermogenesis
- Lipolysis
- Gluconeogenesis
- Proteolysis
- GH receptor expression (permissive)
Involved in foetal brain development
What triggers & inhibits insulin release?
S]
- Blood Glucose
- Blood Amino acids
- Vagal Activity
- Glucagon
- Incretin hormones
I]
- Somatostatin
- Sympathetic (alpha2 receptors)
- Stress e.g. hypoxia
What does insulin do?
Increases:
- Glucose uptake
- Glycogen synthesis
- Amino acid uptake
- Protein synthesis
- TAG synthesis
- K+ Entry to cells
Permissive to GH
Inhibits gluconeogenesis
Antagonizes Cortisol
What is Glucagon?
A peptide hormone produced by Alpha cells in pancreas.
Serves to raise blood glucose
What stimulates/inhibits Glucagon?
S]
- Low blood glucose
- High blood amino acids
- Sympathetic Activity via epinephrine
- Cortisol
- Stressfull stimuli e.g. exercise or infection
I]
- Insulin
- High blood glucose
- Somatostatin
- Free FA/Ketones
What does glucagon do?
- Promotes Gluconeogenesis
- Lipolysis
- Glycogenolysis
What is epinephrine?
A catecholamine produced in adrenal medulla
Serves the fight/flight instinct
What stimulates/inhibits epinephrine?
Sympatetic activity
Functions of epinephrine?
- Peripheral vasodilation
- Lipolysis
- Gluconeogenesis
- Glycogenolysis
What is cortisol?
A steroid hormone (glucocorticoid) produced in the zona fasciculata of the adrenal cortex.
What alters cortisol produciton?
CRH –> ACTH
What does cortisol do?
Immunity:
- Suppresses Immunity
Calcium:
- Inihibits Osteoblasts
- Increases renal Ca2+ excretion
- Decreases Gut Ca2+ Absorption
Thyroid:
- Inhibits TSH release
Glucose:
- Permissive to GLucagon
- Decreases insulin sensitivity
- Proteolysis/Lipolysis/Gluconeogenesis
Water:
- In high concs it functions like aldosterone
Stimulates Somatostatin
Permissive to norepinephrine (vasoconstriction)
How can diabetes cause osteoporosis?
Cortisol inhibits osteoblasts and lowers serum Ca2+
- > More PTH
- > Bone resorption
- > Osteoporosis
Normally insulin antagonizes cortisol, diabetics just get osteoporosis
What is aldosterone?
A steroid hormone (mineralocorticoid) produced in the zona glomerulosa of the adrenal cortex
What stimulates/inhibits aldosterone?
S]
Low blood volume, low BP or hyperosmolar blood through the RAAS
I] opposite
What does aldosterone do?
Increases Na+ reabsorption and K+ excretion at kidney tubule to raise blood volume
What is somatostatin?
AKA GHIH
Trophic peptide hormone produced by the hypothalamus and Delta cells of the pancreas
What stimulates/inhibits somatostatin release?
S] Cortisol REM sleep Free FAs High glucose
What does somatostatin do?
Inhibits GH release
Slows nutrient absorption
Inhibits Glucagon/insulin release
What is parathyroid hormone?
A peptide hormone released by the parathyroid glands
What stimualtes PTH?
Low serum Ca
What does PTH do?
Raises serum calcium by:
- Stimulating calcitriol release from kidney/liver
- inhibits osteoblasts/stimulates osteoclasts
- Increases renal phosphate excretion
- Increases renal Ca2+ reabsorption
What is calcitriol?
aka Active Vit D3 or 1,25-dihydroxycholecalciferol
Steroid hormone released from kidney and liver
What stimulates/inhibits calcitriol?
S]
- PTH
- Prolactin
What does calcitriol do?
Raises serum Ca2+ by:
- Increases Ca2+ absorption from gut
- Increases renal Ca2+ reabsorption
- Stimulates osteoclasts
What is growth hormone?
A trophic peptide hormone releases from the Ant. Pituitary
What stimulates/inhibits Growth Hormone?
S]
- Insufficient energy e.g. hypoglycaemia or exercise/cold
- High Plasma AAs
- Stressfull stimuli (stress.infection)
- Delta sleep
- Sex steroids
I]
- Rem Sleep
- Cortisol
- FAs
- Glucose
What does GH do?
- Cartilage formation in long bones through IGF-1
- Gluconeogenesis
- Decreases insulin sensitivity
- Sensitizes adipocytes to epinephrine (permissive effect)
- Increases AA uptake & protein synthesis
