Oleate, linoleate and cholesterol differently modify aspartyl- and glutamyl-aminopeptidase activities in primary cultures of rat astrocytes

The intake of mono- and polyunsaturated fatty acids has been associated wit h a minor risk of cardiovascular diseases including hypertension. Changes i n levels of fatty acids may also modify the cell activity and may be relate d with alterations in different regulatory processes. Aminopeptidases are z inc-metalloenzymes which metabolise circulating peptide hormones in several tissues. Glutamyl-aminopeptidase (GluAP) and to a lesser extent, aspartyl- aminopeptidase (AspAP), are related with angiotensin metabolism in the reni n-angiotensin system. The present work was designed to study the effect of a range of concentrations (1-100 muM) of oleic and linoleic acids and chole sterol present in the culture medium on the activity of GluAP and AspAP in the culture of rat cerebral cortical astrocytes taken from 21-day-old fetus es. The results showed that oleic acid inhibits, while linoleic acid stimul ates the activity of AspAP. Both fatty acids inhibit the activity of GluAP. Cholesterol stimulates the activity of both enzymes. On the basis of these results, a functional link may exit between the effects of fatty acids on hypertension and the modulation of aminopeptidase activity by these compoun ds in rat astrocytes, as an example of target cell type in the central nerv ous system. (C) 2001 Elsevier Science Inc. All rights reserved.