INVESTIGADORES
GIUSTO Norma Maria
artículos
Título:
Effects of aging on the composition and metabolism of docosahexaenoate-containing lipids of retina
Autor/es:
ROTESTIN, N.P.; ILINCHETA DE BOSCHERO, M.G.; GIUSTO, N.M.; AVELDAÑO, M.I.
Revista:
LIPIDS
Editorial:
SPRINGER HEIDELBERG
Referencias:
Año: 1987 vol. 22 p. 253 - 260
ISSN:
0024-4201
Resumen:
The amount of docosahexaenoate (22:6n-3)-containing phospholipid species
decreases with aging in the rat retina. Most lipids, but especially
choline and serine glycerophospholipids, show a significant fall in
22:6n-3, which is not compensated by increases in other polyenoic fatty
acids. The decrease not only affects 22:6 but also various very long
chain n-3 hexaenoic fatty acids which, in phosphatidylcholine, have up
to 36 carbon atoms, and which are probably synthesized by successive
elongations of 22:6n-3. The in vitro incorporation of [2-3H]glycerol
into retinal lipids indicates that the de novo biosynthetic pathways are
not impaired by aging. The incorporation of [1-14C]docosahexaenoate is
significantly stimulated into all lipids of aged retinas, but to the
largest extent in those showing the largest decreases in 22:6,
especially in choline glycerophospholipids. The results indicate that
the decreased levels of 22:6 with aging are due not to an impaired
activity of the enzymes involved in the synthesis and turnover of
phospholipids but to a decreased availability of this polyene in the
retina. It is suggested that this may stem from a defect in some of the
enzymatic steps that lead to the synthesis of 22:6n-3, probably that
catalyzed by delta 4 desaturase, the effect on longer hexaenes being
secondary to the decreased synthesis of 22:6.