Daily variations of the biosynthesis and composition of fatty acids in rats fed on complete and fat-free diets |
| |
Authors: | I N T de Gómez Dumm M J T de Alaniz R R Brenner |
| |
Affiliation: | (1) CONICET-UNLP, Facultad de Ciencias Médicas, Instituto de Investigaciones Bioquímicas de La Plata (INIBIOLP), calles 60 y 120, 1900 La Plata, Argentina;(2) Present address: Carrera del Investigador Científico, Consejo Nacional de Investigaciones Científicas y Técnicas, Argentina |
| |
Abstract: | This report describes the daily changes in fatty acid composition and fatty acid desaturation in rats feeding on a complete
diet and a fat-free diet successively. Rats on a complete diet showed a good homeostasis in the percentage of fatty acid in
plasma, with a possible palmitic acid rhythm, but the fat-free diet initiated an essential fatty acid-deficient pattern in
a few hours. The light-dark period in animals feeding on a complete diet motivates a feeding rhythm that causes changes in
linoleic and arachidonic acids in the whole liver and microsomes that are related to Δ6 and Δ5 desaturase activities. The
patterns of Δ6 and Δ5 desaturase changes were different. Linoleic acid intake during the dark periods (complete diet feeding)
caused a decrease of Δ6 desaturase activity and the activation of Δ5 desaturation that led to an increase of arachidonic acid
biosynthesis. The feeding of a fat-free diet eliminated the rhythm observed in linoleic and arachidonic acid composition in
the liver and changed the desaturase rhythms. The Δ9 desaturase activity in the liver also showed a daily rhythm in the complete-diet
period that disappeared with the change to a fat-free diet, while the activity increased markedly. A negative correlation
existed between the percentage of linoleic acid in the liver and the Δ9 desaturase activity. However, no correlation was found
between Δ9 desaturase activity and the percentage of 16∶1 and 18∶1 in the complete-diet period. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|