Biomaterial Database

Effects of ethacrynic acid and furosemide on isolated rat kidney mitochondria: inhibition of electron transport in the region of phosphorylation site II. 1976

M A Manuel, and M W Weiner

Previous reports that ethacrynic acid and furosemide inhibit the respiration of isolated mitochondria suggested a direct action of these diuretics on oxidative metabolism. To explore this possibility further, the effects of ethacrynic acid and furosemide on the oxygen consumption of mitochondria isolated from the cortex and outer medulla of rat kidneys were investigated. Both diuretics inhibited state 3 and uncoupled respiration supported by glutamate-malate (which enters the electron transport chain prior to site I) and succinate (which enters prior to site II); respiration supported by tetramethyl phenylene diamine-ascorbate (which enters prior to site III) was relatively unaffected. Biochemical bypass of site II significantly alleviated the respiratory inhibition by both agents. Confirmation of these findings was provided by measurement of the electron transport carriers by dual wavelength spectroscopy, which showed that both diuretics caused a reduction of flavoproteins and an oxidation of the cytochromes. It is concluded that ethacrynic acid and furosemide inhibit oxidative phosphorylation in vitro by inhibiting electron transport through phosphorylation site II.

UI	MeSH Term	Description	Entries
D007668	Kidney	Body organ that filters blood for the secretion of URINE and that regulates ion concentrations.	Kidneys
D008297	Male		Males
D008928	Mitochondria	Semiautonomous, self-reproducing organelles that occur in the cytoplasm of all cells of most, but not all, eukaryotes. Each mitochondrion is surrounded by a double limiting membrane. The inner membrane is highly invaginated, and its projections are called cristae. Mitochondria are the sites of the reactions of oxidative phosphorylation, which result in the formation of ATP. They contain distinctive RIBOSOMES, transfer RNAs (RNA, TRANSFER); AMINO ACYL T RNA SYNTHETASES; and elongation and termination factors. Mitochondria depend upon genes within the nucleus of the cells in which they reside for many essential messenger RNAs (RNA, MESSENGER). Mitochondria are believed to have arisen from aerobic bacteria that established a symbiotic relationship with primitive protoeukaryotes. (King & Stansfield, A Dictionary of Genetics, 4th ed)	Mitochondrial Contraction,Mitochondrion,Contraction, Mitochondrial,Contractions, Mitochondrial,Mitochondrial Contractions
D010085	Oxidative Phosphorylation	Electron transfer through the cytochrome system liberating free energy which is transformed into high-energy phosphate bonds.	Phosphorylation, Oxidative,Oxidative Phosphorylations,Phosphorylations, Oxidative
D010101	Oxygen Consumption	The rate at which oxygen is used by a tissue; microliters of oxygen STPD used per milligram of tissue per hour; the rate at which oxygen enters the blood from alveolar gas, equal in the steady state to the consumption of oxygen by tissue metabolism throughout the body. (Stedman, 25th ed, p346)	Consumption, Oxygen,Consumptions, Oxygen,Oxygen Consumptions
D003576	Electron Transport Complex IV	A multisubunit enzyme complex containing CYTOCHROME A GROUP; CYTOCHROME A3; two copper atoms; and 13 different protein subunits. It is the terminal oxidase complex of the RESPIRATORY CHAIN and collects electrons that are transferred from the reduced CYTOCHROME C GROUP and donates them to molecular OXYGEN, which is then reduced to water. The redox reaction is simultaneously coupled to the transport of PROTONS across the inner mitochondrial membrane.	Cytochrome Oxidase,Cytochrome aa3,Cytochrome-c Oxidase,Cytochrome Oxidase Subunit III,Cytochrome a,a3,Cytochrome c Oxidase Subunit VIa,Cytochrome-c Oxidase (Complex IV),Cytochrome-c Oxidase Subunit III,Cytochrome-c Oxidase Subunit IV,Ferrocytochrome c Oxygen Oxidoreductase,Heme aa3 Cytochrome Oxidase,Pre-CTOX p25,Signal Peptide p25-Subunit IV Cytochrome Oxidase,Subunit III, Cytochrome Oxidase,p25 Presequence Peptide-Cytochrome Oxidase,Cytochrome c Oxidase,Cytochrome c Oxidase Subunit III,Cytochrome c Oxidase Subunit IV,Oxidase, Cytochrome,Oxidase, Cytochrome-c,Signal Peptide p25 Subunit IV Cytochrome Oxidase,p25 Presequence Peptide Cytochrome Oxidase
D004579	Electron Transport	The process by which ELECTRONS are transported from a reduced substrate to molecular OXYGEN. (From Bennington, Saunders Dictionary and Encyclopedia of Laboratory Medicine and Technology, 1984, p270)	Respiratory Chain,Chain, Respiratory,Chains, Respiratory,Respiratory Chains,Transport, Electron
D004976	Ethacrynic Acid	A compound that inhibits symport of sodium, potassium, and chloride primarily in the ascending limb of Henle, but also in the proximal and distal tubules. This pharmacological action results in excretion of these ions, increased urinary output, and reduction in extracellular fluid. This compound has been classified as a loop or high ceiling diuretic.	Edecrin,Etacrynic Acid,Ethacrinic Acid,Ethacrynate Sodium,Ethacrynic Acid, Sodium Salt,Hydromedin,Acid, Etacrynic,Acid, Ethacrinic,Acid, Ethacrynic,Sodium, Ethacrynate
D005665	Furosemide	A benzoic-sulfonamide-furan. It is a diuretic with fast onset and short duration that is used for EDEMA and chronic RENAL INSUFFICIENCY.	Frusemide,Fursemide,Errolon,Frusemid,Furanthril,Furantral,Furosemide Monohydrochloride,Furosemide Monosodium Salt,Fusid,Lasix
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia