Main Hormones Regulating Blood Glucose Levels Flashcards
Which organ is most dependent on extracellular glucose concentration
Brain
Which cells are most damaged by hyperglycaemia
Endothelial cells
Normal blood sugar level
4-5.4 mmol/L before eating
Less than 8 mmol/L 2 hrs after eating
What molecules is glucose converted to for storage
Glycogen
Triglycerides
What is the process of insulin secretion
Glucose enters beta cells -> glucokinase senses glucose -> ATP/ADP ratio incr -> ATP sensitive K channels close -> membrane depolarisation -> voltage gated Ca channels open -> inctracellular Ca incr -> insulin containing granules secreted
What cells secrete insulin
Beta cells
Increase in what intracellular concentration triggers insulin secretion in beta cells
Calcium
What is the role of glucokinase in insulin secretion
Glucose sensor
Which amino acids can stimulate insulin release
Leucine
Arginine
How do amino acids increase intracellular ATP/ADP ratio
Catabolism
What molecules can cause insulin release other than glucose
Leucine
Arginine
Glucagon like peptide 1 GLP1
Glucose dependent insulinotrophic peptide GIP
Fatty acids
ACh
Cholecystokinin
How do muscles and adipocytes take up glucose in response to insulin
GLUT4 translocates to the plasma membrane
What enzyme is activated in muscles in response to insulin
Glycogen synthase
What does glycogen synthase kinase do
Inhibits glycogen synthase
What does insulin stimulate in muscles
Glucose uptake
Glycogen synthesis
What does processes does insulin stimulate and inhibit in adipocytes
Stim Lipogensis
Inhibit lipolysis
How does insulin stimulate lipogenesis
Incr glucose uptake
AcetylCoA carboxylase activation
Incr lipogenic gene expression
How does insulin inhibit lipolysis in adipocytes
Inhibits hormone sensitive lipase preventing hydrolysis of triglycerides
What molecule inhibits beta oxidation of FFAs in adipocytes
Malonyl CoA
What processes does insulin effect in the liver
Incr glucose uptake
Incr glycogenesis
Incr lipogenesis
Inhibits Gluconeogenesis
Which processes are activated in the post absorptive state
Processes releasing glucose and fatty acids
Which hormones are active in the post absorptive state
Glucagon
Insulin counter regulatory hormones
Which cells secrete glucagon
Alpha cells of islets of langerhans
What stimulates glucagon secretion
Low blood glucose concentration
Increased blood amino acids
Exercise
What inhibits glucagon secretion
Hyperglycaemia
GLP-1
Somatostatin
Insulin
Zinc
What type of receptor is the glucagon receptor
G protein coupled receptor
What is the key signalling cascade activated by glucagon
Adenylyl cyclase pathway
How can insulin effect glucagon dependent signalling
Switch off signalling
Which organ does glucagon mainly act on
Liver
Which processes does glucagon stimulate and inhibit
Stim glycogenolysis
Inhibit glycogensis
How does glucagon affect amino acid uptake in liver cells
Increase
How does glucagon affect FA beta oxidation
Increase
How does glucagon affect de novo lipogenesis
Inhibits
What happens to excess acetyl CoA
Converted to ketone bodies
What processes does glucagon increase in the liver
Glycogenolysis
Gluconeogenesis
Lipolysis
What processes does glucagon inhibit in the liver
Glycolysis
Glycogenesis
Lipogenesis
What hormones affect blood glucose concentration other than glucagon and insulin
Catecholamines
Glucocorticoids
Growth hormones
Thyroid hormones
GLP-1
Which cells synthesise catecholamines
Chromaffin cells in adrenal medulla
What molecules are catecholamines synthesised from
Phenylalanine
Tyrosine
Does adrenaline respond to hyper or hypoglycaemia
Hypo
What molecules are corticosteroids formed from
Cholesterol
What regulates glucocorticoid secretion
Hypothalamus/pituitary/adrenal axis
Which hormone is important in resisting stress and inflammation
Glucocorticoids
How does cortisol resist stress and inflammation
Maintains BP
Suppresses inflammation
Does cortisol increase or decrease blood sugar concentration
Increase
What cells secret growth hormone
Somatotroph cells in anterior pituitary
What hormones stimulate and inhibit growth hormone release
Stim by growth hormone releasing hormone
Inhibited by somatostatin
What receptors does growth hormone act on
GH receptor
Prolactin receptor
Which tissues have prolactin receptors
Liver
Muscle
Bone
Adipose
What is the effect of growth hormone in the liver
Incr production and uptake of IDL LDL HDL
What is the overall effect of thyroid hormones
Increase basal metabolic rate
How do thyroid hormones increase basal metabolic rate
Incr HbF and activity of mitochondria
Stim carbohydrate metabolism
Stim fat metabolism
What are Incretins
Group of GI hormones secreted immediately after eating to regulate insulin secretion and decrease blood glucose
What type of hormone is glucagon like peptide 1
Incretin
What tissues does GLP-1 affect
Pancreas
Skeletal muscles
Liver
Adipose
Stomach
