Biochemistry perspective Essay

Diabetes is an ailment which is ca drilld due to high occur of glucose (sugar) in the blood. The main(prenominal) reason for high glucose levels in blood is due to the inability of body to utilize it properly. Glucose comes from the digestion of sugar and foods rich in carbohyd esteems that enable the liver-colored to pee glucose. The high concentration level of glucose in blood is termed as Hyperglycemia. In 1910, Sir Edward Albert Sharpey-Schafer suggested people with diabetes were deficient in a single chemical that was normally decl bed by the pancreas. He proposed calling this substance insulin.The term is derived from the Latin insula, message island, in reference to the islets of Langerhans in the pancreas that produce insulin. (Patlak, 2002) Insulin An Introduction Insulin is a polypeptide containing 51 amino venereal infections arranged in two chains. The chain A contains 21 amino acids and chain B contains 30 residues. These two chains argon cross linked by two sulph ur bridges by cysteine residues. Insulin is tracked by proteolytic cleavage of its 84 amino acid prescursor Proinsulin. Insulin has a molecular weight of 5808 Da. It has the molecular formula C257H383N65O77S6.Insulin structure varies meagerly between species. Its carbohydrate metabolism regulatory flow strength in humans excessively varies. Porcine which is pig insulin is close to humans. The image preceding(prenominal) is computer-generated image of insulin hexamers. The zinc ions holding it together and the histidine residues argon involved in zinc binding. Insulin Action A pharmacological fill of insulin includes carbohydrate metabolism, protein metabolism, lipoid metabolism and other actions. Insulin attachs the use of sugar in the tissue and stimulates theodolite of glucose into the electric cells.Insulin also stimulates protein synthesis and ripening. It increases synthesis of messenger RNA and decreases gluconeogenesis. A gluconeogenesis is a formation of glucose from animal starch. It also increases amino acid usance in the muscle. In adipose tissues, insulin increases eke outty acid synthesis, glycerol phosphate synthesis and triglyceride deposition. other(a) action of insulin includes prevention of ketone boy formation and increases potassium uptake. After the consume of insulin from the pancreatic beta cell into the interstitial compartment, it enters the circulation subsequently crossing endothelial barrier.Insulin action effect at the cellular level is gaind by spark off and suppressing the activity of enzyme. It scum bag also be achieved by changing the rate of synthesis of enzymes at the level of transcription and translation. Insulin stimulate glucose uptake into fat cells by glucose transporters. Glucose transporters are small vesicles which contain specialised protein macromolecules. Insulin increases the rate of optical fusion of these vesicles with the plasma membrane, and activates the transporters to transfer gluco se across the plasma membrane into the cell.Insulin synthesize hoxokinase, an enzyme which phosporylates glucose as soon as it enters the cell. Insulin is an anabolic hormone. It encourages the storage of fats and the synthesis of proteins. Each sensory receptor of insulin contain a pair of of import subunits, which are located on the outer surface of the membrane, and a pair of beta subunits which crosses the membrane and truss out at both the outer and inner surfaces. Both alpha and beta subunits are held together by disulphide (S-S) bonds to form an aggregate. In humans, the insulin receptor gene is located on chromo well-nigh 19.Insulin binds to the receptor at a specific site on the alpha subunit. This causes increased phosphorylation of the receptor by ATP, by and large tyrosine residues of the intracellular portion of the beta subunit. Increased phophorylation of these tyrosine residues activates the beta subunit to function as a kinase enzyme. Some intracellular effects of insulin that occur after insulin-receptor binding may be mediate through nucleotide regulatory proteins (G proteins) a family of proteins associated with the inner surface of the plasma membrane.Cyclic AMP also has some intracellular effects of insulin. The major function of insulin is to counter the concerted action of a number of hyperglycaemia-generating hormones and to maintain low blood glucose levels. Because thither are numerous hyperglycemic hormones, un case-hardened disorders associated with insulin generally lead to severe hyperglycaemia and shortened life span. In addition to its role in adjust glucose metabolism, insulin stimulates lipogenesis, diminishes lipolysis, and increases amino acid transport into cells.Insulin also modulates transcription, altering the cell message of numerous mRNAs. It stimulates dumbfoundth, DNA synthesis, and cell replication, effects that it holds in universal with the insulin-like growth factors (IGFs) and relaxin. Specific prot ease activity cleaves the center third of the molecule, which dissociates as C peptide, leaving the amino terminal B peptide disulfide bonded to the carboxy terminal A peptide. Insulin secernment from beta cells is principally regulated by plasma glucose levels. Increased uptake of glucose by pancreatic b-cells leads to a concomitant increase in metabolism.The increase in metabolism leads to an elevation in the ATP/ADP ratio. This in turn leads to an inhibition of an ATP-sensitive K+ channel. The net emergence is a depolarization of the cell confidential information to Ca2+ influx and insulin secretion. In fact, the role of K+ convey in insulin secretion presents a viable therapeutic target for treating hyperglycemia due to insulin insufficiency. Insulin, secreted by the beta-cells of the pancreas, is directly infused via the portal vein to the liver, where it exerts profound metabolic effects.These effects are the solution of the energizing of the insulin receptor which belon gs to the class of cell surface receptors that exhibit intrinsic tyrosine kinase activity as shown in the figure. Insulin produces its action through specific insulin receptors which consist of two subunits ? and ?. Insulin receptor complex indeed initiates a chain of biochemical reaction involving cAMP, protein phosphorylase, protein kinase, phosphatase and lipase. A diabetic status go out when receptor of insulin is desensitization. Therefore, Insulin is used medically in diabetes mellitus.Patients with type 1 diabetes mellitus depend on insulin (comm altogether injected subcutaneously) for their survival because they make no hormone. Patients with type 2 diabetes mellitus produce either low insulin production or insulin ohmic resistance or both. Therefore, they require insulin administration when other medications become inadequate in haughty blood glucose levels. Actions of insulin-insulin receptor interactions at the level of IRS1 and activation of the kinase cascade lead ing to altered activities of glycogen phosphorylase and glycogen synthase.The insulin receptor is a heterotetramer of 2 excess cellular alpha-subunits disulfide bonded to 2 transmembrane beta-subunits. With respect to hepatic glucose homeostasis, the effects of insulin receptor activation are specific phosphorylation events that lead to an increase in the storage of glucose with a concomitant decrease in hepatic glucose disclose to the circulation. Only those responses at the level of glycogen synthase and glycogen phosphorylase are represented.This image shows Insulin-insulin receptor actions on glycogen homeostasis showing the role of protein targeting glycogen, PTG in complex formations involving many of the enzymes and substrates together. as well diagrammed is response of insulin at the level of glucose transport into cells via GLUT4 translocation to the plasma membrane. GS/GP kinase = glycogen synthase glycogen phosphorylase kinase. PPI = protein phosphatase inhibitor. Arro ws denote either direction of flow or coercive effects, T lines represent inhibitory effects.In most nonhepatic tissues, insulin increases glucose uptake by increasing the number of plasma membrane glucose transporters GLUTs. Glucose transporters are in a continuous state of turnover. Increases in the plasma membrane content of transporters motif from an increase in the rate of recruitment of refreshful transporters into the plasma membrane, lineage from a special pool of preformed transporters localized in the cytoplasm. GLUT1 is present in most tissues, GLUT2 is found in liver and pancreatic b-cells, GLUT3 is in the originator and GLUT4 is found in heart, adipose tissue and skeletal muscle.In liver glucose uptake is dramatically increased because of increased activity of the enzymes glucokinase, phosphofructokinase-1 (PFK-1), and pyruvate kinase (PK), the key regulatory enzymes of glycolysis. Lack of Insulin Usually the inefficiency and lack of insulin are bracketed together, as both situations result in diabetes. There are two types of diabetes, diabetes insipidus and diabetes melitus, which is by far, the most common. Diabetes mellitus in turn has two types casing 1, also known as insulin aquiline diabetes mellitus, IDDMType 1 is characterized by decreased productions of insulin so must(prenominal) be treated with insulin. It is most often found in children and adolescents. Type 2, also known as non-insulin dependent diabetes melitus, NIDDM Type 2 is caused by either decreased insulin production or abnormal cell sensitiveness to the insulin that is present. It may be treated with diet alone, with oral examination hypoglycaemic agents, or with insulin. It is much commonly diagnosed in adults. (Perspective Press, 240-43) Insulin does not cure diabetes. It is and a treatment for the diabetes. Over time, many complications squeeze out occur in diabetic patients taking insulin.Some of these are coronary heart diseases, off-base vascular diabetes , eye disorders, renal failure, and limb amputations. Because of reduced circulation and nerve damage, diabetic patients are essentially prone to developing instauration ulcers, a major cause of amputations. They are able to feel foot infections, which allow it to grow and cause permanent damage. Proper foot care is essential and includes avoiding injuries oral restricting circulations, cleaning wounds, controlling infections, relieving weight from the ulcer area, and improving circulation.A new genetically engineered drug, becaplermin, promotes the healing process in diabetic foot ulcer. Lack of insulin or ineffectiveness of it may induction some response from the body. The predominant tissue responding to signals that indicates fluctuating blood glucose levels is the liver. One of the most central functions of the liver is to produce glucose for circulation. Both elevated and reduced levels of blood glucose trigger hormonal responses to initiate pathways designed to restore gluc ose homeostasis. Low blood glucose triggers bother of glucagon from pancreatic Alpha-cells.High blood glucose triggers release of insulin from pancreatic Beta-cells. In time-honored people pancreas either fails or does not secrete right amount of insulin. In this patient insulin per dig becomes drug of choice when oral antidiabetics have failed. Insulin was also used to induce shocks in schizophrenics. Insulin secretion is controlled by concentrations spread glucose, amino acids, and fatty acids, various hormones and neuron-transmitter agents. In the fasting state, when glucose concentrations are low, insulin secretion is minimal.As glucose concentrations rise after the utilizing carbohydrates meal the raised glucose concentration stimulates insulin secretion. Insulin resistance develops over time. Therefore, processs have to be increased. This occurs because of the development of insulin antibodies in the blood. This also posterior be somewhat corrected by changing the type o f insulin injection and by giving cortiscosteroids which are immunity suppressant drugs. Yet, it also produces disallow effect by increasing blood sugar and this is why they are not used. Types of InsulinThere are many types of insulin and many salt forms of it. It jakes be derived synthetically of from different animal sources such as sound off and pork. There is now genetically engineered human insulin available. Different insulin differs in the tone-beginning of action and the duration of action. Some are mixed together to achieve a desired effect such as a loyal onset but a longer duration of action. The most common mixtures is stiff insulin with NPH insulin (70units NPH and 30 units constant insulin per milliliter) The different categories of insulins are 1.Short-acting insulin types regular insulin (crystalline zinc insulin), semilente insulin (prompt insulin zinc suspension), insulin lipsor 2. Intermediate acting insulin types NPH (isophane insulin suspension) and lin te insulin (insulin zinc suspension) 3. Long-acting insulin types PZI (protamine zinc insulin suspension) and ultralente insulin (extended insulin zinc suspension). Administration Insulin is injection instead of giving orally because it is done for(p) in the gastrointestinal tract. Also, the molecule is too large to be draped by the intestinal membrane.Therefore, injection of soluble crystalline insulin is given by subcutaneous injection which is readily cloaked. Peak effects of insulin are achieved quickly and also excreted quickly within a few hours. However some insulin such as simelente is absorbed slowly. The peak is reached slowly and is sustained. This type of insulin excretory product is also very slow and sometimes partly destroyed by insulinase enzyme in the liver. Controlling glucose level with insulin injections is a complex task since a) Glucose concentrations veer based on food ingestion. b) Cell sensitivity to insulin changes.Exercise increases sensitivity while stress, pregnancy, and some drug decrease insulin sensitivity. As a result some diabetic patients take multiple injections for a short-acting insulin preparation to produce peaks in insulin concentrations and a long acting formulation to establish a baseline concentration. Variable rate infusion pumps are also used. Patients who use insulin need to be instructed on the rotation method of taking their medication. Insulin is absorbed more rapidly with administration in the arm or thigh, particularly with exercise. The abdomen is used for more consistent absorption.Glucose levels should be checked as per physician orders. All insulin must be checked for expiration catch and clarity of the solution. Insulin should not be given if it appears cloudy. Vials should not be shake but rotated in between the hands to mix contents. If regular insulin is to be mixed with NPH or lente insulin, the regular insulin should be drawn into the syringe first. Unopened vials should be stored in the re frigerator, and freezing should be avoided. The vial in use can be stored at room temperature. Vials should not be put in glove compartments, suitcase, or trunks.Humulin is a new type of insulin and is often the patients preference because it can be taken orally. It is imperative that the physician be called if any adverse reactions to the medications are observed. (Jahangir Moini, P 150-154) Undesirable Effects Insulin The main undesirable effect of insulin is hypoglycemia. This is common, and can cause brain damage. Intensive insulin therapy results in a threefold increase in severe hypoglycemia. The treatment of hypoglycemic is to take a sweetish drink or snack, or, if the patient is unconscious, to give intravenous glucose (50% w/v solution) or intramuscular glucagon.Rebound hypergly (Somogyi effect) can follow excessive insulin administration. This results from the release of the insulin-opposing or counter-regulatory hormones in response to insulin-induced hypoglycemia. This can cause hypercemia before eat following an unrecognized hypoglycemic attack during sleep in the early hours of the morning. It is essential to recognize this possibility to avoid the mistake of increasing (rather than reducing) the dose of insulin in this situation. Allergy to insulin is unusual but may take the form of local or systemic reactions.Severe insulin resistance as a consequence of antibody formation is rare. A high tire of circulating anti-insulin antibodies is more likely to occur with bovine than with porcine insulin. Note, however, that virtually all patients treated with animal insulin have antibodies against the hormone, albeit usually flow. Human insulin is less immunogenic than animal insulin but may still evoke an antibody response, since the source of the hormone is not the only determinant of immunogenicity insulin undergo physical changes before and after injection which can increase their potential for provoking an immune response.(HP Rang et al, 200-270) References 1. Patlak M. 2002. New weapons to combat an old-fashioned disease treating diabetes. Available on http//www. fasebj. org/cgi/content/full/16/14/1853e 2. Perspective Press. 2003. The Pharmacy Technician 1st edition Morton Publishers. P 240- 243. 3. Jahangir Moini. 2005. Comprehensive testing Review for the Pharmacy Technician Thomson Delmar. P 150-154 4. H. P. Rang, M. Maureen Dale, James M. Ritter, Philip Moore. 2001. Pharmacology Churchill Livingstone. P 200-270