Biomaterial Database

Effect of hyperthyroidism on the transport of pyruvate in rat-heart mitochondria. 1988

G Paradies, and F M Ruggiero

Department of Biochemistry and Molecular Biology, University of Bari, Italy.

A comparative study of the transport of pyruvate in heart mitochondria from normal and triiodothyronine-treated rats has been carried out. It has been found that the rate of carrier-mediated (alpha-cyanocinnamate-sensitive) pyruvate uptake is significantly enhanced in mitochondria from triiodothyronine-treated rats as compared with mitochondria from control rats. The kinetic parameters of the pyruvate uptake indicate that only the Vmax of this process is enhanced whilst there is no change in the Km value. The enhanced rate of pyruvate uptake is not dependent on the increase of the transmembrane delta pH value (both mitochondria from normal and triiodothyronine-treated rats exhibit the same delta pH value) neither does it depend on the increase of the pyruvate carrier molecules (titration of these last with alpha-cyanocinnamate gives the same total number of binding sites). the pyruvate-dependent oxygen uptake is stimulated by 35-40% in mitochondria from hyperthyroid rats when compared with mitochondria from control rats. There is, however, no difference in either the respiratory control ratios or in the ADP/O ratios between these two types of mitochondria. The heart mitochondrial phospholipid composition is altered significantly in hyperthyroid rats; in particular, negatively charged phospholipid such as cardiolipin and phosphatidylserine were found to increase by more than 50%. Minor alterations were found in the pattern of fatty acids with an increase of 20:4/18:2 ratio. It is suggested that the changes in the kinetic parameters of pyruvate transport in mitochondria from hyperthyroid rats involve hormone-mediated changes in the lipid composition of the mitochondrial membranes which in turn modulate the activity of the pyruvate carrier.

UI	MeSH Term	Description	Entries
D006980	Hyperthyroidism	Hypersecretion of THYROID HORMONES from the THYROID GLAND. Elevated levels of thyroid hormones increase BASAL METABOLIC RATE.	Hyperthyroid,Primary Hyperthyroidism,Hyperthyroidism, Primary,Hyperthyroids
D007425	Intracellular Membranes	Thin structures that encapsulate subcellular structures or ORGANELLES in EUKARYOTIC CELLS. They include a variety of membranes associated with the CELL NUCLEUS; the MITOCHONDRIA; the GOLGI APPARATUS; the ENDOPLASMIC RETICULUM; LYSOSOMES; PLASTIDS; and VACUOLES.	Membranes, Intracellular,Intracellular Membrane,Membrane, Intracellular
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D008297	Male		Males
D008929	Mitochondria, Heart	The mitochondria of the myocardium.	Heart Mitochondria,Myocardial Mitochondria,Mitochondrion, Heart,Heart Mitochondrion,Mitochondria, Myocardial
D010743	Phospholipids	Lipids containing one or more phosphate groups, particularly those derived from either glycerol (phosphoglycerides see GLYCEROPHOSPHOLIPIDS) or sphingosine (SPHINGOLIPIDS). They are polar lipids that are of great importance for the structure and function of cell membranes and are the most abundant of membrane lipids, although not stored in large amounts in the system.	Phosphatides,Phospholipid
D011773	Pyruvates	Derivatives of PYRUVIC ACID, including its salts and esters.
D011919	Rats, Inbred Strains	Genetically identical individuals developed from brother and sister matings which have been carried out for twenty or more generations or by parent x offspring matings carried out with certain restrictions. This also includes animals with a long history of closed colony breeding.	August Rats,Inbred Rat Strains,Inbred Strain of Rat,Inbred Strain of Rats,Inbred Strains of Rats,Rat, Inbred Strain,August Rat,Inbred Rat Strain,Inbred Strain Rat,Inbred Strain Rats,Inbred Strains Rat,Inbred Strains Rats,Rat Inbred Strain,Rat Inbred Strains,Rat Strain, Inbred,Rat Strains, Inbred,Rat, August,Rat, Inbred Strains,Rats Inbred Strain,Rats Inbred Strains,Rats, August,Rats, Inbred Strain,Strain Rat, Inbred,Strain Rats, Inbred,Strain, Inbred Rat,Strains, Inbred Rat
D011956	Receptors, Cell Surface	Cell surface proteins that bind signalling molecules external to the cell with high affinity and convert this extracellular event into one or more intracellular signals that alter the behavior of the target cell (From Alberts, Molecular Biology of the Cell, 2nd ed, pp693-5). Cell surface receptors, unlike enzymes, do not chemically alter their ligands.	Cell Surface Receptor,Cell Surface Receptors,Hormone Receptors, Cell Surface,Receptors, Endogenous Substances,Cell Surface Hormone Receptors,Endogenous Substances Receptors,Receptor, Cell Surface,Surface Receptor, Cell
D002352	Carrier Proteins	Proteins that bind or transport specific substances in the blood, within the cell, or across cell membranes.	Binding Proteins,Carrier Protein,Transport Protein,Transport Proteins,Binding Protein,Protein, Carrier,Proteins, Carrier