Absorptive & Post-Absorptive State & Diabetes Flashcards
Absorptive state =
nutrients being absorbed into blood (fed)
Post-absorptive state =
nutrients not being absorbed into blood (fasting)
Glucose transporter responsible for glucose uptake in to pancreatic beta cells
GLUT-2
Glucose transporter unregulated on body cells by insulin
GLUT-4
What is happening to nutrients in the absorptive state
insulin is stimulating their conversion to storage products
glycogen, protein, triglycerides
What is happening to nutrients in the post-absorptive state
storage products are being broken down to preserve blood glucose level
Absorptive state:
What effect does insulin have on the liver?
stimulates glycogen synthesis, lipogenesis, protein synthesis
- glucose is stored as glycogen and triglycerides
- protein synthesis
inhibits glycogenolysis, lipolysis and protein catabolism
Absorptive state:
What effect does insulin have on adipose tissue?
stimulates lipogenesis
- glucose is stored as triglycerides
- free fatty acids are stored as triglycerides
inhibits lipolysis
Absorptive state: What effect does insulin have on the muscle?
stimulates glycogen synthesis and protein synthesis
- glucose is stored as glycogen
- amino acids are stored as protein
inhibits glycogenolysis and protein catabolism
Why is there metabolic disturbance in diabetes
Lack/resistance to insulin
- high blood glucose as glucose not taken into cells by GLUT4 transporter
- compounded by no inhibition of glyogenolysis or lipolysis by insulin
Which hormones are associated with the post-absorptive state
adrenaline, glucagon and growth hormone
action of glucagon in the post-absorptive state
increased glycogen breakdown in liver
action of adrenaline in the post-absorptive state
increased glycogen breakdown in liver, muscle, adipose tissue
action of growth hormone in the post-absorptive state
decreased glucose uptake to
Symptoms of diabetes
large volume of urine (polyuria) due to osmotic diuresis
thirst (polydipsia) due to dehydration
blurred vision
infections eg thrush due to impaired immune response
weight loss due to breakdown of fat and muscle
ketosis (high level of ketone bodies)
confusion
coma
What energy sources does the body use in diabetes
protein and fat
triglycerides degraded to free fatty acids (lipolysis) - FFAs are put through beta oxidation in the liver to make (energy +) acetyl coA which is used in the krebs cycle or converted to ketone bodies
protein catabolism
why do you get glycosuria in diabetes
renal threshold for glucose reabsorption is met
What do ketone bodies do
Made in the liver, from acetyl CoA
Circulate in blood and taken into tissues, converted back to acetyl coA and used in krebs cycle
Why is hypokalaemia a side effect of insulin treatment
Insulin activates Na/K ATPases on cells which causes K influx into the cell
This lowers plasma K level
How to treat uncontrolled diabetes
Rehydration with IV saline - fluid loss may be massive
Insulin
Monitor electrolytes (hypokalaemia)
Microvascular complications in diabetes include
retinopathy - Inappropriate angiogenesis in retina creates poor quality vessels leading to vision loss & blindness
nephropathy - damage to the kidney which can lead to chronic renal failure, eventually requiring dialysis. COMMON
neuropathy - abnormal and decreased sensation initially with feet later often fingers and hands. When combined with damaged blood vessels this can lead to diabetic foot (delayed wound healing, infection or gangrene of the foot)
Explain how atherosclerosis is a complication of diabetes
Hyperlipidaemia common in diabetes. (high circulating fatty acid concentration)L. ipids are released into the circulation as VLDL and LDL – these are atherogenic
How can diabetes cause a fatty liver?
Fatty acids taken up by liver and converted to triacylglycerol. This can be deposited
in the liver and lead to tissue damage – hepatic steatosis “fatty liver”
How do ketone bodies cause ketoacidosis
They dissociate in the blood producing H+ which causes acidosis
