DIETARY LINOLENIC ACID-MEDIATED INCREASE IN VASCULAR PROSTACYCLIN FORMATION

To define vascular effects of an enhanced dietary alpha-linolenic acid intake, 28 spontaneously hypertensive rats were fed a 3% sunflowersee d oil (44% linoleic acid) diet; in 3 groups (7 rats each), the diet wa s supplemented with 1, 2.5 or 5% linseed oil containing 62% alpha-lino lenic acid. alpha-Linolenic acid was incorporated up to 12% in the aor ta of the 5% linseed oil group. The eicosapentaenoic acid content was not significantly increased. The content of arachidonic acid and docos atetraenoic acid was moderately reduced in rats fed 5% linseed oil. Th e generation of 6-keto-PGF(1 alpha) (degradation product of prostacycl in) assessed by HPLC/electrochemical detection was, however, markedly increased (p < 0.05) in rats fed 2.5 and 5% linseed oil. The minor pro stanoids TXB(2), PGE(2) and PGF(2 alpha) were not significantly altere d. The high systolic and diastolic blood pressure of SHR monitored by radio telemetry was more effectively reduced (p < 0.05) in the light, i.e. sleep, cycle. An increased prostacyclin formation and lowered vas cular arachidonic acid content associated with enhanced dietary alpha- linolenic acid intake would thus be expected to prove beneficial in th e prevention of vascular disorders.