Development of cytochrome-c oxidase activity in rat heart: downregulation in newborn rats.
Cytochrome-c oxidase (COX) activity of the rat heart was two- to sevenfold activated when the membrane integrity was disrupted by hypotonic swelling, freezing-thawing, or a detergent, indicating that a large portion of COX capacity in intact mitochondria is not active. The effect of detergent was tested in heart mitochondria isolated from 1-, 5-, 15-, 29-, and 60-d-old rats; activation by detergent was up to 20-fold in 1-d-old animals, whereas in mitochondria from 60-d-old rats it was only 7-fold. Our data indicate that the rat heart exhibits significant developmental changes dependent on downregulation of COX activity in the neonatal period.
Drahota
Z
Z
Center for Integrated Genomics, Academy of Sciences of the Czech Republic, Videnska 1083, 142 20 Prague 4, Czech Republic.
Milerova
M
M
Stieglerova
A
A
Skarka
L
L
Houstek
J
J
Ostadal
B
B
D000375:Aging / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D000831:Animals, Newborn; D002478:Cells, Cultured; D003902:Detergents / Q000008:administration & dosage; D015536:Down-Regulation / Q000187:drug effects; D003576:Electron Transport Complex IV / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects / Q000502:physiology*; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects / Q000502:physiology*; D006321:Heart / Q000187:drug effects; D008297:Male; D008929:Mitochondria, Heart / Q000187:drug effects / Q000201:enzymology*; D009206:Myocardium / Q000201:enzymology*; D051381:Rats; D017208:Rats, Wistar
D003902:Detergents; D003576:Electron Transport Complex IV