title: Differential effects of thyroid status on regional H₂O₂ production in slow- and fast-twitch muscle of ducklings.
abstract: Birds seem to employ powerful physiological strategies to curb the harmful effects of reactive oxygen species (ROS) because they generally live longer than predicted by the free radical theory of aging. However, little is known about the physiological mechanisms that confer protection to birds against excessive ROS generation. Hence, we investigated the ability of birds to control mitochondrial ROS generation during physiologically stressful periods. In our study, we analyzed the relationship between the thyroid status and the function of intermyofibrillar and subsarcolemmal mitochondria located in glycolytic and oxidative muscles of ducklings. We found that the intermyofibrillar mitochondria of both glycolytic and oxidative muscles down regulate ROS production when plasma T₃ levels rise. The intermyofibrillar mitochondria of the gastrocnemius muscle (an oxidative muscle) produced less ROS and were more sensitive than the pectoralis muscle (a glycolytic muscle) to changes in plasma T₃. Such differences in the ROS production by glycolytic and oxidative muscles were associated with differences in the membrane proton permeability and in the rate of free radical leakage within the respiratory chain. This is the first evidence which shows that in birds, the amount of ROS that the mitochondria release is dependent on: (1) their location within the muscle; (2) the type of muscle (glycolytic or oxidative) and (3) on the thyroid status. Reducing muscle mitochondrial ROS generation might be an important mechanism in birds to limit oxidative damage during periods of physiological stress.
authors: Laboratoire de Biométrie et Biologie Evolutive, Université de Lyon, CNRS-UMR 5558 Université Lyon 1, Villeurbanne Cedex, France. benjamin.rey@univ-lyon1.fr
authors: Benjamin
authors: B
authors: Rey
authors: Damien
authors: D
authors: Roussel
authors: Jean-Louis
authors: JL
authors: Rouanet
authors: Claude
authors: C
authors: Duchamp
mesh_terms: D000064:Acclimatization; D000818:Animals; D017849:Animals, Inbred Strains; D002463:Cell Membrane Permeability / Q000187:drug effects; D003080:Cold Temperature / Q000009:adverse effects; D004372:Ducks / Q000097:blood / Q000378:metabolism*; D005602:France; D006019:Glycolysis / Q000187:drug effects; D020249:Hormone Replacement Therapy / Q000662:veterinary; D006861:Hydrogen Peroxide / Q000378:metabolism*; D007037:Hypothyroidism / Q000188:drug therapy / Q000503:physiopathology / Q000662:veterinary*; D008297:Male; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D008931:Mitochondria, Muscle / Q000187:drug effects / Q000378:metabolism; D018656:Muscle Fibers, Fast-Twitch / Q000187:drug effects / Q000378:metabolism*; D018657:Muscle Fibers, Slow-Twitch / Q000187:drug effects / Q000378:metabolism*; D010085:Oxidative Phosphorylation / Q000187:drug effects; D018384:Oxidative Stress / Q000187:drug effects; D011201:Poultry Diseases / Q000188:drug therapy / Q000503:physiopathology*; D011897:Random Allocation; D017382:Reactive Oxygen Species / Q000378:metabolism; D013961:Thyroid Gland / Q000187:drug effects / Q000378:metabolism / Q000503:physiopathology*; D014284:Triiodothyronine / Q000097:blood / Q000378:metabolism / Q000627:therapeutic use
chemical_list: D017382:Reactive Oxygen Species; D014284:Triiodothyronine; D006861:Hydrogen Peroxide