Respiratory chain complexes and membrane fatty acids composition in rat testis mitochondria throughout development and ageing.
Throughout the maturation of germ cells, a morphological, biochemical and functional differentiation of mitochondria has been shown to occur. Ageing is known to cause changes involved in energy metabolism. These changes have been related to molecular and functional alterations in the properties of biological membranes. Variations in membrane lipid composition and lipid-protein interactions occur with ageing in several tissues. The present paper describes the relationship between these membrane alterations and the activities of lipid-dependent enzymes of isolated testis mitochondria in rats of from 10 days of age to 24 months. The specific activities of these enzymes are lower in preparations from adult and aged rats as compared to those from young rats. Temperature breaks of Arrhenius plots show age-dependent shifts to higher temperatures for the NADH-dehydrogenase, succinate-dehydrogenase, cytochrome c oxidase, and ATPase in senescent animals. Analysis of the membrane fatty acid composition reveals a distinct age-dependent fall in the content of polyunsaturated fatty acids accompanied by an increase in the proportion of saturated fatty acids and a decrease in polyunsaturated fatty acid percentage. The results suggest that during spermatogenesis and the ageing process some changes in the composition of the fatty acids in the surrounding membrane affect the protein-lipid interactions, producing a decrease in mitochondrial enzyme activities.
Instituto Mexicano del Seguro Social, Unidad de Investigación Médica en Genética Humana, Centro Médico Nacional Siglo XXI-IMSS. Apdo Postal 73-032, México, DF CP 06725, Mexico. elisavazquezm@prodigy.net.mx
Martha E
ME
Vázquez-Memije
María J
MJ
Cárdenas-Méndez
Adela
A
Tolosa
Mohammed El
ME
Hafidi
D000251:Adenosine Triphosphatases / Q000378:metabolism; D000375:Aging / Q000378:metabolism*; D000818:Animals; D002462:Cell Membrane / Q000201:enzymology; D004579:Electron Transport / Q000502:physiology; D045222:Electron Transport Chain Complex Proteins / Q000378:metabolism*; D003576:Electron Transport Complex IV / Q000378:metabolism; D005231:Fatty Acids, Unsaturated / Q000032:analysis*; D008297:Male; D008928:Mitochondria / Q000201:enzymology*; D009097:Multienzyme Complexes / Q000378:metabolism; D009245:NADH Dehydrogenase / Q000378:metabolism; D010085:Oxidative Phosphorylation; D010743:Phospholipids / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013091:Spermatogenesis / Q000502:physiology; D013385:Succinate Dehydrogenase / Q000378:metabolism; D013737:Testis / Q000201:enzymology*
D045222:Electron Transport Chain Complex Proteins; D005231:Fatty Acids, Unsaturated; D009097:Multienzyme Complexes; D010743:Phospholipids; D013385:Succinate Dehydrogenase; D009245:NADH Dehydrogenase; D003576:Electron Transport Complex IV; D000251:Adenosine Triphosphatases