Physiological Pharmaceutics

Glossary 289Glucose-6-phosphate dehydrogenase (G-6-PD) Anenzyme which dehydrogenates glucose-6-phosphate to form 6-phopshoglucon. This isthe initial step in the pentose phosphatepathway of glucose catabolism.Glucuronic acid Important acid in humanmetabolism by virtue of its detoxifying action.Glucuronosyltransferases Liver enzymes responsiblefor blucuronidation of xenobiotics.Glutamine The monoamide of aminoglutaric acid.It is present in the juices of many plants and isessential in the hydrolysis of proteins.Glutamic oxaloacetic transaminase A metabolicenzyme found in liver and heart tissue which isreleased into the bloodstream by tissue damage,and hence used as a therapeutic indicator.Glutamic pyruvic transaminase see glutamicoxaloacetic transaminase.Glutathione A tripeptide of glutamic acid, cysteineand glycine. Important in cellular respiration.Glycerol A simple polyhydric alcohol, propane 1,2, 3-triol.Glyceryl trinitrate. See nitroglycerin.Glycine The simplest amino-acid.Glycocalyx A thin layer of glycoprotein andpolysaccharide which covers the surface ofsome cells such as muscle.Glycofurol A polar solvent used mainly in cosmeticsand creams.Glycogen A polysaccharide commonly called animalstarch. The conversion of glycogen to glucoseis called glycogenolysis. Glycogen is the formby which carbohydrate is stored in the body.Glycolipids Lipids with an attached sugar molecule.Glycoprotein A protein with an attachedpolysaccharide chain, often membraneresidentand conferring antigenic properties.Glycosaminoglycan A mucopolysaccharide foundin cell walls and mucus.Goblet cells Secretes mucus in the gastrointestinaland respiratory tracts.Gradient-charged system A controlled release systemin which the concentration of drug variesthroughout its thickness in order to achieve aspecified release profile.Gramicidin D An antibiotic.Greenhouse gases Gases which absorb solar infraredradiation, causing an elevation in the Earth’stemperature.Griseofulvin An antifungal agent. It’s poor watersolubility led to its being used as a model drugfor a wide range of formulation studies.Guar gum A plant polysaccharide used as a viscositymodifier, pharmaceutical excipient, and foodadditive.Guinea pig Small furry animal so widely used forexperimental studies that it has given its nameidiomatically to anyone or anything who isthe subject of a novel experiment or trial.Gut associated lymphoid tissue (GALT) term appliedto all lymphoid tissue associated with thegastrointestinal tract incluuding tonsils,appendix and Payer’s patches. It is responsiblefor controlling the entry of organisms via thegastrointestinal tract.HH + /K + ATPase The active transporter systemresponsible for pumping acid (H - ) into thegastric lumen.H 1receptors Histamine receptors found in the cellsof the bronchiole muscle.H 2receptors Histamine receptors found in the cellsthat secrete gastric acid.Haemoglobin The mammalian oxygen transportprotein located in the erythrocytes.Haemolysis Disintegration of red blood cells withthe release of haemoglobin.Haemorrhoidal plexus The network of blood vesselssurrounding the anal canal.Haustra Sacculated pouches of the colon.Hayfever Hypersensitivity of the eye and upperrespiratory tract to inhaled pollens.Heartburn See gastro-oesophageal reflux.Helicobacter pylori An organism which livesbeneath the mucus layer in the stomach and isassociated with gastritis.HEMA See hydroxyethyl methacrylate.Hemidesmosomes See desmosomes.Heparin A polysaccharide which inhibits bloodcoagulation.Hepatic flexure The junction of the ascending andtransverse colon.Hepatic portal vein See also first pass metabolism.Only main vein in the body which does not godirectly to the heart. It links the gastrointestinaltract to the liver.Hexose transporter system An active transportsystem which transfers hexoses across the cellmembrane.HFAs See hydrofluoroalkanes.Histamine A substance produced from the aminoacid histidine. It is released from injured cells.Histamine increases gastric secretion,dilatation of capillaries and contraction ofbronchial smooth muscle.Histidine An amino acid obtained by hydrolysisfrom tissue proteins, necessary for tissue repairand growth.Histiocytes A macrophage present in all looseconnective tissue.HIV infection Human immunodeficiency virus alsoknown as AIDS (acquired immune deficiencysyndrome).Horseradish peroxidase Used to study aqueouspathways between cells.Housekeeper contractions See migrating myoelectriccomplex.Humidification saturation of air with water, esp. inthe nose, so that the airflow does not dehydratedeeper tissuesHyaluronic acid An acid mucopolysaccharide foundin the ground sustance of connective tissue thatacts as a binding and protective agent. Also