Glucose, quantitative determination

Hormonal regulation of blood glucose

Methods Chemical Enzymatic

CHEMICAL METHODS Oxidation - Reduction Methods Condansation Methods Folin – Wu Somogyi - Nelson Condansation Methods Orto - Toluidine

Benedict reaction

Glucose + Cu2+ >>>Gloconate + Cu+ Folin - Wu Glucose + Cu2+ >>>Gloconate + Cu+ pH > 7 , heat Cu+ + phosphomolybdate Blue molybdenium complex λ = 660 nm

Glucose + Cu2+ >>> Gloconate + Cu+ Somogyi - Nelson Glucose + Cu2+ >>> Gloconate + Cu+ pH > 7 , heat Cu+ + arsenomolybdate >>> blue molybdenium complex λ = 660 nm

O - Toluidine Method o - Toluidine + Glucose >>> Glycosylamine pH < 7 , heat Schiff Base λ = 630 nm color complex NH2 CH3

Interference Bilirobin Galactose Mannose Hemoglobin

Enzymatic Methods Glucose Oxidase Hexokinase Glucose dehydrogenase

Glucose Oxidase α -D-Glucose β-D-Glucose O2 Gluconic acid + H2O2 Mutarotase α -D-Glucose β-D-Glucose O2 glucose oxidase Gluconic acid + H2O2 Peroxidase H2O2 + chromogen Color complex (o-dianisidine) + H2O (phenylamine) λ = 520 nm

Glucose oxidase Inhibited by High concentrations of uric acid, ascorbic acid, bilirubin, glutathione, creatinine. L-cysteine, L-dopa. Dopamine, methyldopa and citric acid

Hexokinase method

Glucose dehydrogenase method

Clinical Significance F.B.S (Fasting Blood Suger) Fasting 12 - 14 hours Normal Range 70 - 110 mg/dL Decrease Hypoglycemia Increase Hyperglycemia

Criteria for the diagnosis of diabetes mellitus

Diagnosis of Pre-Diabetes and Diabetes Mellitus

Hyperglycemia FBS > 140 mg/dL Primary (Diabetes Mellitus) IDDM (type I) NIDDM (type II)

Insulin Dependent Diabetes Mellitus (IDDM) Absolute deficiency of insulin Make up about 10% of all patients with D.M. IDDM persent at an early age (usually before 30) Clinical signs : Blood glucose Insulin (decreased) Ketosis Loss of body weight

Noninsulin Dependent Diabetes Mellitus (NIDDM) Deficiency of insulin receptor Patients are commonly obese NIDDM is the most common from of D.M. ( 80-90%) Usually first present at an age over 40 Clinical signs Blood glucose Insulin Osmotic diuresis Dehydration

Characteristics of Type 1 and Type 2 Diabetes

Response of plasma insulin to glucose stimulation

Secondary hyperglycemia Pancratectomy Acromegaly Cushing’s syndrome Glucagonoma

Hypoglycemia Adult < 45 - 50 mg/dL in fasting Infant Preterm < 25 mg/dL Fullterm < 35 mg/dL

Causes of hypoglycemia Insulinoma (islet cell tumors) Glycogen Storage Diseases (GSD) Addison’s disease

OGTT Fasting 80 mg/dL 0.5 155 mg/dL 1 165 mg/dL 2 140 mg/dL 3 80 mg/dL

Oral Glucose Tolerance Tests (OGTT)

Screening and diagnosis of gestational diabetes mellitus

OGTT curve

2hpp 2hpp (two hours postprandial plasma glucose) To screen for diabetes mellitus To monitor glucose control

Glycated hemoglubin HbA1c

an index of average blood glucose levels over the past 2-4 months. People without diabetes have HbA1c levels between 4-6%. Measure HbA1C levels every 3-6 months to monitor glycemic control

Put 10 minute in boil water bath read at 630 nm Ct = At / Ast * Cst