Carbohydrates PDF

07/11/2024 CARBOHYDRATES JO L O JA M E S CHR I S TI AN N. D A DI O S , R M T, DT A OBJECTIVES AT THE END OF THIS UNIT OF STUDY, THE STUDENTS SHOULD BE ABLE TO: Classify carbohydrates into their respective groups. Discuss the metabolism of carbohydrates in the body and the mode...

07/11/2024 CARBOHYDRATES JO L O JA M E S CHR I S TI AN N. D A DI O S , R M T, DT A OBJECTIVES AT THE END OF THIS UNIT OF STUDY, THE STUDENTS SHOULD BE ABLE TO: Classify carbohydrates into their respective groups. Discuss the metabolism of carbohydrates in the body and the mode of action hormones in carbohydrate metabolism. Diff. the types of diabetes by clinical symptoms and laboratory findings according to the ADA  07/11/2024 CARBOHYDRATES Major food source and energy supply for the body. Stored primarily in the liver and muscle as glycogen. Disease states involving carbohydrates are split into two groups- hyperglycemia and hypoglycemia. Hydrates of aldehyde or ketone derivatives based on the location of the carboxyl group. Carbohydrates: monosaccharides, disaccharides, oligosaccharides, and polysaccharides. CARBOHYDRATES Glucose is the only carbohydrate to be directly used for energy or stored as glycogen with the help of insulin. All sugars must be digested to this monosaccharide.  07/11/2024 GENERAL DESCRIPTION Carbohydrates are compounds containing C, H, and O. The general formula for carbohydrate is Cx(H2O)y. All carbohydrates contain C=O and -OH functional groups. GENERAL DESCRIPTION The classification of carbohydrates is based on four structural properties: The size of the base carbon chain. The location of the CO function group. The number of sugar units. The stereochemistry of the compound.  07/11/2024 CLASSIFICATION Carbohydrates can be grouped into generic classifications based on the number of carbons in the molecule. For example: trioses contain three carbons tetroses contain four pentoses contain five hexoses contain six.  07/11/2024 CLASSIFICATION Carbohydrates are hydrates of aldehyde or ketone derivatives based on the location of the CO functional group ALDOSE FORM KETOSE FORM THE ALDOSE FORM HAS A TERMINAL THE KETOSE FORM HAS A CARBONYL CARBONYL GROUP (O=CH–) CALLED GROUP (O=C) IN THE MIDDLE LINKED AN ALDEHYDE GROUP. TO TWO OTHER CARBON ATOMS O H (CALLED A KETONE GROUP). \\ / CH2OH C | | C=O H– C–OH | | R R STEREOCHEMISTRY Mirror image forms D= right side OH, L= left side OH Same chemical formula different configuration D and L designations are based on the configuration about the single asymmetric C  07/11/2024 STEREOCHEMISTRY Haworth Projection Fischer Projection refers to the position of the refers to the position of -OH in the anomeric C1 hydroxyl group AWAY from ALPHA: below the aldehyde functional BETA: Above group CHEMICAL PROPERTIES OF CARBOHYDRATES REDUCING SUBSTANCES Some carbohydrates are reducing substances; these carbohydrates can reduce other compounds To be reducing, the carbohydrate must contain an active ketone or an aldehyde group.  07/11/2024 CHEMICAL PROPERTIES OF CARBOHYDRATES NON-REDUCING SUBSTANCES Nonreducing carbohydrates do not have an active ketone or aldehyde group. They will not reduce other compounds. The most common nonreducing sugar is sucrose—table sugar. BASIC INFO. All carbohydrates are reducing sugars except SUCROSE The simplest of all common aldose is GLYCERALDEHYDE  07/11/2024 CLASSIFICATION BASED ON THE NUMBER OF SUGAR UNITS IN THE CHAIN Monosaccharides Disaccharides Oligosaccharides Polysaccharides MONOSACCHARIDE Simple sugar that cannot be hydrolyzed to a simpler form Can contain three, four, five, or six or more carbons (trioses, tetroses, etc.) The most common hexose monosaccharides are glucose, galactose and fructose Important pentose sugars include ribose and 2-deoxyribose  07/11/2024 MONOSACCHARIDE Glucose The primary source of energy for humans. Central point of carbohydrate metabolism. Use to assess total carbohydrates for measuring blood glucose level. Fructose Fruit sugar Not synthesized by the body Galactose Galactose ----> Glucose, before it can be used by the body GALACTOSEMIA- condition with difficulty in conversion to glucose OTHERS: Ribose and Deoxyribose MONOSACCHARIDE NICE TO KNOW ABOUT FRUCTOSE aka Levulose component of sucrose found in high concentration seminal fluid not classified as a blood sugar (non-saccharoid)  07/11/2024 QUESTION 1 The only monosaccharide that is directly used for energy by the cells is: A. Galactose B. Fructose C. Glucose D. Lactose DISACCHARIDES Formed by the interaction of two monosaccharides Separated by hydrolysis (process), hydrolase (enzyme), hydrogen bond (cutting) Sucrose Glucose + Fructose Table sugar Enzyme: sucrase Lactose Glucose + Galactose Milk sugar Enzyme: lactase Maltose Glucose + Glucose Cooked sweet potato Enzyme: maltase  07/11/2024 QUESTION 2 Hydrolysis of lactose by lactase will yield: A. 2 molecules of glucose B. Glucose and Fructose C. Glucose and Galactose D. Galactose and Fructose LACTOSE INTOLERANCE Due to lactase enzyme deficiency on or in the intestinal lumens, which is needed to metabolize lactose. (INABILITY TO DIGEST LACTOSE) Results in an accumulation of lactose in the stomach as waste lactic acid- causing stomach upset and discomfort  07/11/2024 OLIGOSACCHARIDES Most oligosaccharides act as a soluble fiber, which may help prevent constipation Ingestion of large amount of oligosaccharides can result in abdominal bloating and excessive gas (flatulence) Raffinose Galactose + Glucose + Fructose Beans, cabbage, broccoli Stachyose 2 Galactose + Glucose + Fructose cannot be digested well by humans. Beans and legumes POLYSACCHARIDES Starch Primary carbohydrates in the diet and found in most plants. Numerous glucose Glycogen The storage form of CHO many connected glucose glycogen is broken down to release glucose into the bloodstream to be used as fuel for the cells. Cellulose (Plants) Main substance for plant cells. It cannot digest by humans, but important in the diet as fiber. Hundreds to thousands of C, H, O  07/11/2024 QUESTION 3 Starch is hydrolyzed by amylase to produce what immediate product A. Glycogen B. Maltose C. Glucose D. Lactose GLUCOSE METABOLISM After glucose is absorbed it can go into one of three metabolic pathways The ultimate goal is to convert glucose to CO2 and H2O Requires ATP and ADP, O2 in the final step NADH acts as intermediate--> ATP is gained  07/11/2024 GLUCOSE METABOLISM Salivary Amylase source: salivary glands Inactivated by acid pH as it arrives in the stomach Pancreatic Amylase source: Pancreas Route: small intestine-pH is increased Intestinal Enzymes DIGESTION OF DISACCHARIDES Sucrose -> Fructose + Glucose Lactose -> Galactose + Glucose Maltose -> Glucose + Glucose GLUCOSE METABOLISM  07/11/2024 GLUCOSE METABOLISM 1st step in all pathway is Glucose is converted to glucose-6-phosphate using ATP-catalyzed by hexokinase. Glucose-6-phosphate enters the pathways: Embden_Meyerhoff (glucose  pyruvate) Hexose Monophosphate Glucogenesis (storage of glucose as glycogen) EMBDEN-MEYERHOFF  07/11/2024 HORMONE REGULATION Hormones affect the entry of glucose into cells and fate in the cells within the body. As needed hormones regulate the release of glucose Hormones work together to meet 3 requirements: A steady supply of glucose Store excess glucose Use stored glucose as needed PANCREAS Two functionally different tissue Endocrine (Hormone releasing) Consists of the Islet of Langerhans- 4 cell types Secrete 4 hormones: Insulin (BETA), glucagon (ALPHA), gastrin, and somatostatin (DELTA) Exocrine (enzyme secreting)  07/11/2024 PANCREATIC DISORDER The major disorders of the pancreas are: Endocrine pancreas Diabetes Mellitus (DM) Islet Cell Tumors Exocrine pancreas Acute pancreatitis and chronic pancreatitis Pancreatic cancer Cystic fibrosis  07/11/2024 HORMONES THAT REGULATE GLUCOSE METABOLISM Glucagon ACTH (Adrenocorticotropic hormone) Growth Hormone Cortisol Human Placental Lactogen Epinephrine Thyroxine Insulin INSULIN Primary hormone responsible for the entry of glucose into cell and therefore reducing blood glucose levels. Synthesized by the Beta cells of Islets of Langerhans Regulate blood glucose by increasing: Glycogenesis Glycolysis Lipogenesis Decreases: Glycogenolysis  07/11/2024 GLUCAGON Primary hormone responsible increasing blood glucose Synthesized by the alpha cells of the islets of langerhan Regulates blood glucose by increasing: Glycogenolysis Gluconeogenesis EPINEPHRINE Produced by the adrenal medulla, increase blood glucose Released during times of physical and emotional stress Regulates blood glucose by increasing: Inhibition of insulin secretion Glycogenolysis Lipolysis  07/11/2024 CORTISOL Produced by the adrenal cortex in response to ACTH, increased plasma glucose Regulates blood glucose by: decrease intestinal entry of glucose into the cell Increase gluconeogenesis and lipolysis Decrease glycogenesis GROWTH HORMONE Produced by the anterior pituitary gland increased plasma glucose regulates blood glucose by: Decrease intestinal entry of glucose into the cell Increase glycogenolysis  07/11/2024 THYROXINE (T4) Produced by the thyroid gland Increase plasma glucose Regulates blood glucose by: Increase gluconeogenesis, glycogenolysis, and glucose intestinal absorption SOMATOSTATIN Acts like insulin Produced by the Delta cells of the islet of langerhans in the pancreas and hypothalamus Increases plasma glucose by inhibition of insulin, glucagon, and growth hormone  07/11/2024 ACTH Enhances release of cortisol Enhances release of fatty acids from adipose tissue Promotes gluconeogenesis HUMAN PLACENTAL LACTOGEN Increases during pregnancy Main function: Increase gluconeogenesis Promotes insulin resistance  07/11/2024 QUESTION Which inhibit growth hormone secretion? A. Glucose loading B. Amino acids C. Thyroxine deficiency D. Insulin deficiency E. A, B, and C HYPERGLYCEMIA Increase in blood glucose concentration Toxic to beta cell function and impairs insulin secretion. Causes: stress, severe infection, dehydration or pregnancy, pancreatectomy, insulin deficiency, or abnormal insulin receptor FBS level= greater than or equal to 126 mg/dl Diagnosis by glucose tolerance and postprandial glucose testing Adult >45 yrs old should have routine FBS every 3 years  07/11/2024 CHARACTERISTICS OF UNCONTROLLED HYPERGLYCEMIA: Polyuria Ketonuria Glycosuria CLASSIFICATION OF DIABETES Diabetes can be classified into the following general categories: 1. Type I Diabetes (due to autoimmune b-cell destruction, usually leading to absolute insulin deficiency) 2. Type II Diabetes (due to progressive loss of b-cell insulin secretion frequently on the background of insulin resistance) 3. Gestational Diabetes Mellitus (diabetes diagnosed in the second or third trimester of pregnancy that was not clearly overt diabetes prior to gestation) 4. Specific Type of Diabetes due to other causes: E.g., monogenic diabetes syndromes (such as neonatal diabetes and maturity-onset diabetes of the young [MODY]), diseases of the exocrine pancreas (cystic fibrosis), and drug-or chemical-induced diabetes (such as with glucocorticoid use, in the treatment of HIV/AIDS, or after organ transplantation.  07/11/2024 RISK FACTORS FOR DIABETES Obesity Family History in 1st degree relative History of GDM or > 9 lb baby Hypertension >140/90 Low HDL cholesterol 250 mg/dL) METABOLIC SYNDROME Central obesity Dyslipidemia Prehypertension Elevated fasting glucose levels  07/11/2024 CLASSIFICATION OF DIABETES Type 1 Diabetes AKA: Juvenile onset, Brittle DM Ketosis prone Diabetes and IDDM Characterized by insulinopenia Require treatment with insulin to sustain life. Most individuals exhibit it as an autoimmune disorder Genetic association with HLA DR3 and DR4 Primary symptoms include polyuria, polydipsia, polyphagia, rapid weight loss, hyperventilation, and confusion. Ketosis-prone: can produce excess ketones. CLASSIFICATION OF DIABETES Type 1 Diabetes Absence of insulin with excess glucagon. It requires absolute INSULIN REPLACEMENT to prevent ketosis Has a genetic association with HLA DR3 and DR4 of MHV complex chromosome 6  07/11/2024 CLASSIFICATION OF DIABETES Type 1 Diabetes Autoantibodies Anti-islet cells Anti-glutamic acid decarboxylase (GAD65) Anti-insulin Anti-Tyrosine phosphatase IA-1, IA-2B, and ZnT8 Source: Diabetes Care, ADA Guideline  07/11/2024 Criteria for Screening for Diabetes or Prediabetes in Asymptomatic Adults 1. Testing should be considered in adults with overweight or obesity (BMI ≥25 kg/m2 or ≥23 kg/m2 in Asian American individuals) who have one or more of the following risk factors:  First-degree relative with diabetes  High-risk race/ethnicity (e.g., African American, Latino, Native American, Asian American, Pacific Islander)  History of CVD  Hypertension (≥130/80 mmHg or on therapy for hypertension)  HDL cholesterol level 250 mg/dL (2.82 mmol/L)  Individuals with polycystic ovary syndrome  Physical inactivity  Other clinical conditions associated with insulin resistance (e.g., severe obesity, acanthosis nigricans) 2. People with prediabetes (A1C ≥5.7% [39 mmol/mol], IGT, or IFG) should be tested yearly. 3. People who were diagnosed with GDM should have lifelong testing at least every 3 years. 4. For all other people, testing should begin at the age of 35 years. 5. If results are normal, testing should be repeated at a minimum of 3-year intervals, with consideration of more frequent testing depending on initial results and risk status. 6. People with HIV. CLASSIFICATION OF DIABETES Type 2 Diabetes AKA: Adult type, Maturity onset, Stable diabetes, Ketosis resistant, and receptor-deficient DM Defects in insulin secretion and cellular resistance to insulin Individuals are not dependent on treatment with insulin Associated with strong genetic predisposition but not related to autoimmunity: Geneticist’s nightmare Milder than type DM 1 Non-ketosis prone  07/11/2024 CLASSIFICATION OF DIABETES Type 2 Diabetes Hyperglycemia is controlled often without insulin replacement TYPE II DIABETES  07/11/2024 TYPE II DIABETES DIABETES MELLITUS COMPLICATIONS Nephropathy Neuropathy Retinopathy Cardiovascular Disease  07/11/2024 LABORATORY FINDINGS IN HYPERGLYCEMIA Increased glucose in plasma and urine If urine glucose is present, the appropriate follow-up test is KETONES Increased urine specific gravity Increased serum and urine osmolality Ketones in serum and urine Decreased blood and urine pH (acidosis) Electrolyte imbalance  07/11/2024 Serum osmolality Urine Osmolality Diabetes insipidus (no ADH) Inc Dec SIADH (excess ADH) Dec Inc DM Inc Inc TESTS FOR LONG TERM DM COMPLICATIONS Serum BUN Serum Creatinine Urine albumin Lipids  07/11/2024 RECOMMENDED TEST FOR DM EVERY YEAR Blood Glucose HBA1c- Microalbumin Estimated Glomerular Filtration Rate POCT GESTATIONAL DIABETES MELLITUS Onset of diabetes mellitus during pregnancy due to metabolic or hormonal changes Glucose intolerance that is induced by pregnancy After birth, the individual generally returns to normal metabolism. However, there is an increased chance that type 2 diabetes mellitus may develop later in life (5-10 years post-natal in 30-40% of cases) Risk factors: macrosomia, hypoglycemia, hypocalcemia, polycythemia, hyperbilirubinemia Screening: 24-28 weeks Repeat Testing: 6-12 weeks after delivery  07/11/2024 GESTATIONAL DIABETES MELLITUS CHARACTERISTICS: Insulin resistance and decreased insulin secretion result in hyperglycemia Obese women Women greater than 25 years old Previous gestational diabetes Ethnic group GESTATIONAL DIABETES MELLITUS  07/11/2024 Guidelines for Administration of OGTT 1. Patient is asked to consume 150 g carbohydrate a day for 3 days prior to test 2. Patient to fast overnight and avoid excessive physical activity 3. Measure fasting glucose level before giving glucose 4. If fasting glucose >140 mg/dL: Terminate or stop the test 5. If fasting glucose phosphomolybdic acid or phosphomolybdenum blue  07/11/2024 NON-ENZYMATIC METHODS I. Alkaline Copper Reduction Method: C. Neocuproine Cuprous ions + neocuproine --> cuprous neocuproine complex (yellow/yellow-orange) D. Benedict’s Method Detection and quantitation of reducing substances in body fluids like blood and urine. Use citrate or tartrate as a stabilizing agent. NON-ENZYMATIC METHODS II. Ferric Reduction Method A. Hagedorn-Jensen Ferric reduction method (inverse colorimetry) Glucose + ferricyanide (yellow) --> Ferrocyanide (colorless) III. Ortho-toluidine (Dubowski Method) Condensation of carbohydrates with aromatic amines producing Schiff bases (green)  07/11/2024 ENZYMATIC METHODS I. Colorimetric Glucose oxidase (Saifer Gernstenfield) B-D-glucose + O2 +H2O --glucose oxidase --> gluconic acid + H2O2 H2O2 + reduce chromogen (o-Dianisidine) --peroxidase --> oxidized (o-Dianisidine) chromogen -red dye +H2O II. Hexokinase Glucose+ ATP- hexokinase --> glucose 6-PO4 +ADP Glucose 6-PO +NADP+ -G-6-PD --> NADPH +H+ +6- phosphogluconate III. Glucose dehydrogenase Glucose + NAD -- Glucose Dehydrogenase (mutarotase) --> NADPH + H+ + D-gluco-g-Lactone THANK YOU FOR LISTENING