Impaired catecholamine inactivation. A prohypertensive stimulus after dietary linoleate deficiency in salt-loaded rats?
Experiments were carried out on salt-loaded rats (1.5% NaCl as drinking fluid) to further explore the mechanisms by which blood pressure increases after a linoleic acid-deficient (LAd) diet. In 4-week-old LAd rats (0.5 cal% LA, hydrogenated palm kernel fat) compared to linoleic acid-rich rats (LAr, 13.3 cal% LA, sunflower oil), we observed, from the base of a reduced content of omega-6-polyunsaturated fatty acids in the tissues, an increase in blood pressure by 12 mm Hg (p less than 0.001), a diminished formation of prostaglandin E (PGE), and an unchanged formation of PGF in the aorta as well as a reduction in the in vitro uptake of 14C-norepinephrine into cardiac, aortic, and renal tissues, and a reduced degradation rate of 14C-norepinephrine in cardiac tissue. These differences in LAr vs LAd rats were not exaggerated. With respect to aortic PGE formation, 14C-norepinephrine uptake into aortic and renal tissues and 14C-norepinephrine degradation even lessened when the diet was begun prenatally, although the reduction of omega 6-polyunsaturated fatty acids in the tissues was aggravated. Our conclusion is that a fault in catecholamine inactivation may be involved in the pathogenesis of increased sympathetic activity and blood pressure elevation in LAd-fed, salt-loaded rats, possibly via alterations of endogenous prostanoid formation.
D000818:Animals; D001011:Aorta / Q000378:metabolism; D001794:Blood Pressure; D001835:Body Weight; D002250:Carbon Radioisotopes; D004032:Diet; D015232:Dinoprostone; D005231:Fatty Acids, Unsaturated / Q000378:metabolism; D005260:Female; D006973:Hypertension / Q000209:etiology*; D007668:Kidney / Q000378:metabolism; D019787:Linoleic Acid; D008041:Linoleic Acids / Q000172:deficiency*; D008297:Male; D009206:Myocardium / Q000378:metabolism; D009638:Norepinephrine / Q000378:metabolism*; D011247:Pregnancy; D011458:Prostaglandins E / Q000096:biosynthesis; D011460:Prostaglandins F / Q000096:biosynthesis; D051381:Rats; D011919:Rats, Inbred Strains; D012965:Sodium Chloride / Q000008:administration & dosage
D002250:Carbon Radioisotopes; D005231:Fatty Acids, Unsaturated; D008041:Linoleic Acids; D011458:Prostaglandins E; D011460:Prostaglandins F; D012965:Sodium Chloride; D019787:Linoleic Acid; D015232:Dinoprostone; D009638:Norepinephrine