FATTY-ACID METABOLISM IN NORMOTENSIVE AND HYPERTENSIVE RATS .2. DISTRIBUTION AND OXIDATION OF DIETARY [1-14C]-18-2N-6 AND [1-14C]-18-3N-3

To determine whether genetically normotensive and hypertensive rats differentially oxidize and incorporate dietary n-3 and n-6 fatty acids, male Wistar Kyoto (WKY) and spontaneously hypertensive (SHR) rats (n=36/strain) were placed on fat-free semi-purified diet for 8 weeks following weaning. After a 12 hr fast they received an i.g. bolus of [1-14C]-18:2n-6 or [1-14C]-18:3n-3 (28μg) in 0.4 ml olive oil. Animals were killed at 2, 8, and 24 hr post administration (n=6/strain) and tissues were collected for assessment of 14C incorporation. Also, the 24 hr group was placed in metabolic boxes and expired 14CO2 was measured at 2, 4, 6, 8, and 24 hr post administration in order to approximate whole body oxidation. In WKY and SHR, oxidation of 18:3 exceeded that of 18:2. In SHR, 18:2 and 18:3 oxidation was greater than that of WKY, and the ratio of oxidized 18:3 vs. 18:2 was greater than in the WKY. In addition, in adipose tissue, incorporation of [1-14C]-18:3-derived 14C, but not of [1-14C]-18:2-derived 14C, was reduced in the SHR vs. WKY. Incorporation of 14C from [1-14C]-18:2 was increased in liver, lung, skeletal muscle, heart, and brain of SHR vs. WKY and that from [1-14C]-18:3 was increased in kidney, heart, and brain of SHR vs. WKY. These data suggest that the hypertensive SHR exhibits differences in its utilization of n-3 and n-6 fatty acids vs. the normotensive WKY. These differences suggest that the SHR may be less responsive to dietary n-3 fatty acid manipulation than the WKY, and that the dietary requirements for n-3 fatty acids may be higher in the SHR than the WKY. © 1990 Pergamon Press plc. All rights reserved.