Biomaterial Database

Hypothyroid state and membrane fatty acid composition influence cardiac mitochondrial pyruvate oxidation. 1995

D J Pehowich

Department of Oral Biology, University of Alberta, Edmonton, Canada.

Pyruvate oxidation was measured in cardiac mitochondria from euthyroid and hypothyroid rats fed diets enriched with either omega-6 or omega-3 fatty acids. Both State 4 and State 3 rates of pyruvate-dependent respiration were markedly reduced in hypothyroid mitochondria, regardless of diet consumed, compared to euthyroid controls. Respiratory control ratios and ADP/O ratios were the same under all treatments. While there was no significant effect of diet on respiration in euthyroid mitochondria, pyruvate oxidation was 28% higher in hypothyroid mitochondria from animals fed the omega-3 diet compared to those fed the omega-6 diet. Depressed respiration in the hypothyroid state was correlated with 18% more phosphatidylcholine in the inner mitochondrial membrane whereas phosphatidylethanolamine was 17% lower and cardiolipin 32% lower compared to controls. The total phospholipid fatty acid composition was not affected by the hypothyroid state. However, enhanced respiration in hypothyroid animals fed the omega-3 diet was associated with a 3-fold increase in monounsaturated fatty acids in the cardiolipin fraction, and a 12-fold increase in omega-3 fatty acids, primarily 22:5(omega-3) and 22:6(omega-3). The data suggest that membrane levels of cardiolipin and its omega-3 fatty acid content modulate pyruvate transport in hypothyroid mitochondria.

UI	MeSH Term	Description	Entries
D007037	Hypothyroidism	A syndrome that results from abnormally low secretion of THYROID HORMONES from the THYROID GLAND, leading to a decrease in BASAL METABOLIC RATE. In its most severe form, there is accumulation of MUCOPOLYSACCHARIDES in the SKIN and EDEMA, known as MYXEDEMA. It may be primary or secondary due to other pituitary disease, or hypothalamic dysfunction.	Central Hypothyroidism,Primary Hypothyroidism,Secondary Hypothyroidism,TSH Deficiency,Thyroid-Stimulating Hormone Deficiency,Central Hypothyroidisms,Deficiency, TSH,Deficiency, Thyroid-Stimulating Hormone,Hormone Deficiency, Thyroid-Stimulating,Hypothyroidism, Central,Hypothyroidism, Primary,Hypothyroidism, Secondary,Hypothyroidisms,Primary Hypothyroidisms,Secondary Hypothyroidisms,TSH Deficiencies,Thyroid Stimulating Hormone Deficiency,Thyroid-Stimulating Hormone Deficiencies
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
D008297	Male		Males
D008563	Membrane Lipids	Lipids, predominantly phospholipids, cholesterol and small amounts of glycolipids found in membranes including cellular and intracellular membranes. These lipids may be arranged in bilayers in the membranes with integral proteins between the layers and peripheral proteins attached to the outside. Membrane lipids are required for active transport, several enzymatic activities and membrane formation.	Cell Membrane Lipid,Cell Membrane Lipids,Membrane Lipid,Lipid, Cell Membrane,Lipid, Membrane,Lipids, Cell Membrane,Lipids, Membrane,Membrane Lipid, Cell,Membrane Lipids, Cell
D008929	Mitochondria, Heart	The mitochondria of the myocardium.	Heart Mitochondria,Myocardial Mitochondria,Mitochondrion, Heart,Heart Mitochondrion,Mitochondria, Myocardial
D010084	Oxidation-Reduction	A chemical reaction in which an electron is transferred from one molecule to another. The electron-donating molecule is the reducing agent or reductant; the electron-accepting molecule is the oxidizing agent or oxidant. Reducing and oxidizing agents function as conjugate reductant-oxidant pairs or redox pairs (Lehninger, Principles of Biochemistry, 1982, p471).	Redox,Oxidation Reduction
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
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.
D004041	Dietary Fats	Fats present in food, especially in animal products such as meat, meat products, butter, ghee. They are present in lower amounts in nuts, seeds, and avocados.	Fats, Dietary,Dietary Fat,Fat, Dietary