Hypothyroidism in rats decreases mitochondrial inner membrane cation permeability

• Published in: FEBS letters Vol. 248; no. 1-2; pp. 175 - 178
• Main Authors: Hafner, Roderick P., Leake, Michael J., Brand, Martin D.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 08.05.1989; Elsevier
• Subjects: Acetates - metabolism; Acetic Acid; Animals; Biological and medical sciences; Cation leak; Cell physiology; Fundamental and applied biological sciences. Psychology; H+/O, number of protons released to the external bulk phase/oxygen atom reduced; Hypothyroidism - metabolism; Intracellular Membranes - metabolism; Membrane and intracellular transports; Membrane potential; Membrane Potentials; Mitochondria; Mitochondria - metabolism; Mitochondrial Swelling; Molecular and cellular biology; Oxygen Consumption; Ph3MeP+, methyltriphenylphosphonium cation; Phosphorylation; potassium; Proton leak; Protons; Quaternary Ammonium Compounds - metabolism; Rats; Respiration rate, non-phosphorylating; thyroid hormone; Thyroid hormone action; Mitochondria; Proton leak; Membrane potential; Cation leak; Respiration rate, non-phosphorylating; Ph3MeP+, methyltriphenylphosphonium cation; Thyroid hormone action; H+/O, number of protons released to the external bulk phase/oxygen atom reduced; Membrane electrode; Rat; Liver; Rodentia; Peptide hormone; Proton transfer; Theoretical study; Ion transport; Biomembrane; Thyroid gland; Hypothyroidism; Biological activity; Internal membrane; Vertebrata; Mammalia; Cations; Potassium; Cell respiration; Ultraviolet visible spectrometry
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/0014-5793(89)80455-7

We investigated the cation permeability of liver mitochondria isolated from hypothyroid or euthyroid rats by measuring the rate of swelling of respiring mitochondria in acetate salts as a function of membrane potential. Mitochondria from hypothyroid rats have a decreased permeability of roughly 3-fold in the presence of monovalent cations K and tetramethylammonium at any (measured) membrane potential. Since the monovalent cation leak and the proton leak are known to respond similarly to membrane potential our results support the theory that the difference in non-phosphorylating respiration rate between mitochondria from hypothyroid and euthyroid rats is due to a difference in proton leak.