Glucose regulators + Chemical Methods Flashcards
Together with the hormones epinephrine, cortisol and GH oppose many actions of insulin.
- It increases glucose by stimulating glycogenolysis and gluconeogenesis in the liver.
Glucagon
It increases blood glucose by activating adenylate cyclase to produce cAMP which further activates the enzyme phosphorylase causing increased glycogenolysis .
- Like glucagon, it is responsible for short-term glucose regulation.
Epinephrine
- It increases blood glucose primarily by stimulating gluconeogenesis by promoting
protein catabolism and deamination and it inhibits glucose metabolism in peripheral tissues. - Like the GH, it promotes long-term regulation of blood glucose.
Cortisol
- It increases blood glucose by inhibiting uptake of glucose by cells and due to its antagonistic action on insulin.
Growth Hormone
- It inhibits both insulin and glucagon.
Somatostatin
- It increases blood glucose by stimulating glycogenolysis, accelerating degradation of insulin and promoting absorption of glucose in the intestinal tract..
Thyroid Hormone
- It is produced by the chromaffin cells of the adrenal medulla.
Epinephrine
- It is produced by the alpha-cells of the islets of Langerhans of the pancreas.
Glucagon
- It is produced by the fascicular cells of the adrenal cortex upon stimulation by adrenocorticotropic hormone (ACTH).
Cortisol
- It is produced by the anterior pituitary gland.
Growth Hormone
- It is synthesized by the thyroid follicles of the thyroid gland.
Thyroid Hormone
- It is produced by the delta-cells of the islets of Langerhans of the pancreas.
Somatostatin
Specimens for blood glucose determination (4)
serum
plasma
whole blood
CSF
Serum or plasma normal glucose range
50-110mg/dL (2.8 - 6.2 mmol/L)
-the conversion factor from mg% to mM is 0.055
NOTE:
Delay in glucose testing would requirePrompt separation of clot from serum is a must since glucose is utilized by the RBCs lowering the value by 5% per hour of serum-clot contact.
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CSF normal glucose range
40 – 70 mg/dL
(60 – 75% of the level in serum or plasma)
Delay in glucose testing would require?
fluoride or iodoacetate.
Two (2) mg of NaF per ml of whole blood to prevent glycolysis for 48 hours at 4 deg Celsius.
test employed in testing urine sugars.
Benedict – modification of Folin-Wu
(reduction method)
titrimetric method using iodine to oxidize cuprous oxide formed and the excess iodine in the blank and the sample is titrated with thiosulfate.
Schaeffer-Hartmann-Somogyi
(reduction method)
adapted to automation; mple is deproteinized
Neocuproine -
(reduction method)
whole blood is deproteinized using 10%
Folin-Wu
(reducing method)
Serum is deproteinized
Somogyi-Nelson
(reduction method)
uses ferricyanide ions instead of cupric ions
Hagedorn-Jensen
- considered as the most specific nonenzymatic for glucose
Dubowski (Ortho-toluidine method
(condensation method)
- glucose is converted into hydroxymethylfurfural in hot strong acid and reacts with the enol tautomer of anthrone to form a green product
Anthrone condensation
vitamin C interferes in the test.
Glucose Oxidase (GOD) Coupled Reaction
This is based on the consumption of oxygen
Polarographic GOD Method
The most specific method and therefore the reference method for glucose determination.
Hexokinase Method
