The Metabolic Basic Of Disase

The Metabolic Basic Of Disase

1. the metabolic pathways in living organisms has been a prerequisite to understanding the nature of many diseases

   • 1908 Archibald Garrod appreciated that diseases can be caused by the genetically determined absence or modification of specific enzymes
     • Garrod reported only four cases
       • These hereditary defects of metabolism are rare, can have disastrous consequences for the young children who are affected, for example:
         • Phenylketonuria, cystic fibrosis and galactosaemia.

2. Metabolic fuels derived of

   • Carbohydrates, fats and proteins

3. Diagnosis of an inherited metabolic disorder can involve measuring the activity of a given enzyme in a sample taken from an accessible tissue, such as blood cells.

4. ·

   • If a patient lacks enzyme consequences may be observed.d, the following Reduced formation of E and X. If either o condition may result r both are essential cell products, with no alternative route for their synthesis, a deficiency ccumulation of C and possibly A. If these substances are toxic, cell damage mayresult Increased levels of Z.
     • The production of this molecule is now enhanced and it may be toxic.The increased amounts of C and Z may accumulate in the blood and, subsequently, can be excreted in the urine.
       • example of a metabolic disorder
         • phenylketonuria, which results from the inability to convert the amino acid phenylalanine (C) into tyrosine (E).This is due to the lack of phenylalanine hydroxylase (enzyme d) activity, which is normally present in the liver.
   • cystic fibrosis
     • he defective gene is associated with a chloride ion channel in epithelial cells, which results in abnormal elec- trolyte reabsorption

5. Cholera a usurper of intestinal metabolism

   • is an infectious disease, contracted by drinking water containing the bacterium Vibrio cholerae.
     • The vibrios colonize and adhere to the sma secrete a protein exotoxin called choleragen
       • The toxine molecule is made in two parts, knows as subunits A and B. Subunit B Binds strongly to a specific, complex lipid repector in the cell membrane. Subunit A,wich is responsible for cell toxicity, then gains entry to the cell.

6. Diabetes mellitus: catabolic disease

   • principal characteristic
     • High blood golucose concentrations
       • In the kidneys, filtered glucose isas exceeded reabsorbed, but when blood glucose levels of 10 mM a gh blood glucose concentrations (hyper- rom an increased ke by muscle and reab- normally mpl sorption becomes saturated and glucose appear osmotically enhances water excretion and stimulae classical symptoms of the diseases in the urine
       • In non-diabetics, the blood glucose will havereturned normal levels, whereas in the diabetic it will remain high above 11 mM.
   • insulina
     • be an anabolic hormone that functions to coordinate the metabo processes in a number of body tissues. A lack of insulin will, therefore lead to enhanced catabolism

7. Alcoholic liver disease: damage by metabolism

   • increased formation of fibrous tissue destroys the normal liver lobule structure and seriously disturbs hepatic functions
     • alcohol abuse aver a period of 10-20 years can result in cirrhosts
   • The principal enzymes involved are alcohol dehydrogenase (ADH), located in the cytoplasm and aldehyde dehydrogenase (ALDH), predominantly associated with mitochondria
     • Alcohol metabolism inhibit liver gluconeogenesis from lactate and amino acids This can be explained as a result of alcohol oxidation by the ADH reaction increasing the amount of NADH relative to NAD in the cytolpasm.
       • Through the reaction catalysed by LDH, this will reduce the availability of pyruvate, thereby restricting its involvement in gluconeo- genesis.

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