Age-related depletion of linoleic acid desaturation in liver microsomes from young spontaneously hypertensive rats.

The present study was designed to investigate the microsomal interconversion of linoleic acid (LA) into arachidonic acid (AA) in young spontaneously hypertensive rats (SHR), in relation to the pathogenesis of hypertension. Our results show lower delta 6 and delta 5 desaturase activities (the limiting steps in the bioconversion of LA into AA) in young SHR, as compared to Wistar Kyoto normotensive rats. This impairment of desaturase activities is raised when the blood pressure increases and is related to the age of animals. The fatty acid composition of liver lipids shows a lower proportion of AA and a higher proportion of LA in SHR than in normotensive rats, confirming the depletion of the enzymatic system studied. Such a loss of desaturase activity may be under the control of hormones involved in the regulation of SHR blood pressure.