|
|
||||||||
AJP - Regulatory, Integrative and Comparative Physiology, Vol 261, Issue 6 1438-R1445, Copyright © 1991 by American Physiological Society
ARTICLES |
C. Duchamp, H. Barre, J. L. Rouanet, A. Lanni, F. Cohen-Adad, G. Berne and P. Brebion
Laboratoire de Thermoregulation et Energetique de l'Exercice, Centre National de la Recherche Scientifique, Lyon, France.
In cold-acclimatized (CA) king penguin chicks exhibiting nonshivering thermogenesis (NST), protein content and cytochrome oxidase (CO) activity of tissue homogenates were measured together with protein content, CO, and respiration rates of isolated mitochondria from skeletal muscle (gastrocnemius and pectoralis) and liver. The comparison was made with chicks reared at thermoneutrality (TN) for at least 3 wk. In CA chicks showing a NST despite the lack of brown adipose tissue, an increase in thermogenic capacity was observed in skeletal muscle in which the oxidative capacity rose (+28% and +50% in gastrocnemius and pectoralis muscles, respectively), whereas no change occurred in the liver. Oxidative capacity of skeletal muscle increased together with the development of mitochondrial inner membrane plus cristae in muscles of CA chicks contrary to their TN littermates (+30 to +50%). Subsarcolemmal mitochondria of CA chicks had a higher protein content (+65% in gastrocnemius muscle) and higher oxidative capacities than in controls. The lower respiratory control ratio of these mitochondria might result from a low ADP phosphorylation rate. No change occurred in the intermyofibrillar fraction nor in liver mitochondria. These findings together with earlier results obtained in cold-acclimated ducklings indicate the marked and suited adaptation of skeletal muscle and in particular of subsarcolemmal mitochondria allowing them to play a role in NST.
This article has been cited by other articles:
![]() |
B. Rey, L. G. Halsey, V. Dolmazon, J.-L. Rouanet, D. Roussel, Y. Handrich, P. J. Butler, and C. Duchamp Long-term fasting decreases mitochondrial avian UCP-mediated oxygen consumption in hypometabolic king penguins Am J Physiol Regulatory Integrative Comp Physiol, July 1, 2008; 295(1): R92 - R100. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. L. Barger, B. M. Barnes, and B. B. Boyer Regulation of UCP1 and UCP3 in arctic ground squirrels and relation with mitochondrial proton leak J Appl Physiol, July 1, 2006; 101(1): 339 - 347. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |