glucose Flashcards
(29 cards)
how many hormones regulate glucose
at least six
where is insulin produced
beta cells of islets of langerhans
where is glucagon produced
alpha cells of the islets of langerhans
does glucagon affect muscle or hepatic glycogen
hepatic glycogen - no effect on muscle glycogen
apart from glucose what else does insulin work on
stimulates production of proteins and fatty acids
what is on the criteria for blood glucose testing
BMI >25 , physically inactive, family history of diabetes, hypertension, high TGCs, high cholesterol, women birthing baby >9lbs, PCOS, abnormal diet, renal damage, frequent thirst
what are the regular blood glucose levels
4.7.5mmol/L
2hrs after lunch = 4.5 - 8.5
morning (fasting) = 4 - 6
how to convert mmol/L glucose to mg/dL
multiply by 18.02
what is the preferred specimen for glucose assay
fasting serum, sodium fluoride
whole blood can be used in patients where a limited sample is present i.e paediatrics
what happens to monosaccharides when used as a reduced agent
reducing agent where carbonyl (C=O) is oxidsed to a carboxyl group (COOH)
write a note on Folin-Wu copper reduction method
hot alkaline solution - glucose reduces cupric to cupric ions, where cupric ions are oxidised to cuprous oxide.
cuprous oxide reduces phosphomolybdic acid to molybdenum blue. this complex is measured at 430nm
what are sources of error of Folin-Wu copper reduction method
this method measures all reducing substances present such as uric acid, creatinine, and sulphydrl compounds to cause a positive error
write a note on Ferricyanide method
yellow ferricyanide ion = reduced by glucose to colourless ferrocyanide ion where the decrease in yellow = measured
glucose + Fe(CN)3-6 > Fe(CN)4-6
these ions can also be measured directly with reaction via excess ferric ions to form blue ferric ferrocyanide
sources of error with ferricyanide method?
specificity affected by other reducing substances - not ideal for uremic patients
what type of acids are carbs oxidised to with Br2, Tollens and Benedict’s reagent
aldonic acids i.e gluconic acid
write note on glucose oxidase
glucose + water + o2 <–glucose oxidase–> gluconic acid + H2O2
O-dianisidine + H2O2 <–peroxidase–> oxidised o-dianisidine + H2O
measured at 500nm - brown colour produced
what is a different reaction for glucose oxidase
glucose + water + o2 <–glucose oxidase–> gluconic acid + H2O2
H2O2 + phenol + 4-aminoantipyrine <–peroxidase–> quinone dye (pink) + 4H2O
write note on hexokinase method
transferral of phosphate group from ATP to glucose to form glucose - 6- phosphate and ADP where G6P is used in coupled reaction
G6P —G6P dehydrogenase–> 6-phosphogluconate
release of NADPH from reduction of NADP+ read at 340nm
write note on glucose dehydrogenase
glucose + NAD+ <–GDH–> gluconolactone + NADH + H+
NADH generated = measured at 340nm
highly specific, no interference with normally present substances
when do symptoms of hyperglycaemia emerge
levels 15-20mmol/L
write note on hypoglycaemia
biochemical sign for diseases: endocrine disorders, liver disease, metabolic disorders, GI surgery.
rapid onset = sweating, shaking, weakness, anxiety
slow onset = headache, irritated, lethargy
causes = diabetic patients (excess insulin, low carb intake, alcohol consumption), kidney failure, sepsis, liver disease, medicine
write note on T1D
loss of B cells in pancreas, autoimmune, early development in life, insulin deficiency
T2D
stage 1 = insulin resistance via insulin receptors becoming defectively responsive
stage 2 = inc demand for insulin = pancreas loses ability to secrete enough to respond to meals
peripheral tissues become resistant to actions of insulin - insulin levels may be high or normal
write note on gestational diabetes
pregnancy, associated with high BP and high Glucose levels. usually resolves after birth, more likely to develop T2DM later
