Dietary fish protein lowers blood pressure and alters tissue polyunsaturated fatty acid composition in spontaneously hypertensive rats

• Published in: Nutrition (Burbank, Los Angeles County, Calif.) Los Angeles County, Calif.), 2003-04, Vol.19 (4), p.342-346
• Main Authors: Ait-Yahia, Dalila, Madani, Sihem, Savelli, Jean-Luc, Prost, Josiane, Bouchenak, Malika, Belleville, Jacques
• Format: Article
• Language: English
• Subjects: 6-Ketoprostaglandin F1 alpha - urine; Animals; Antihypertensive Agents - administration & dosage; Arterial hypertension. Arterial hypotension; Biological and medical sciences; Blood and lymphatic vessels; Blood pressure; Blood Pressure - drug effects; Body Weight - drug effects; Cardiology. Vascular system; Caseins - metabolism; Clinical manifestations. Epidemiology. Investigative techniques. Etiology; desaturation; Diet; Dietary Fats, Unsaturated - metabolism; Dietary Proteins - administration & dosage; Fatty Acid Desaturases - metabolism; Fatty acids; Fatty Acids, Unsaturated - metabolism; Fish; fish protein; Fish Proteins - administration & dosage; Fish Proteins - pharmacology; hypertension; Hypertension - diet therapy; Lipid Metabolism; Lipids; Lipids - chemistry; Liver; Liver - anatomy & histology; Liver - metabolism; Male; Medical sciences; Metabolites; Microsomes, Liver - enzymology; Organ Size - drug effects; polyunsaturated fatty acid synthesis; Polyunsaturated fatty acids; Prostaglandins F - urine; Proteins; Rats; Rats, Inbred SHR; Rodents; spontaneously hypertensive rats
• ISSN: 0899-9007; 1873-1244
• DOI: 10.1016/S0899-9007(02)00858-4

To investigate the effect of two types of dietary protein on blood pressure, liver fatty acid desaturation and composition, and urine 6-keto-prostaglandin-F (PGF 1α) level, the metabolite of prostacyclin. 5-wk-old spontaneously hypertensive rats were fed 20% casein or purified fish protein. The fat source was 5% ISIO oil, which contains 47.9% (ω-6) and 1.7% (ω-3) total polyunsaturated fatty acids. After 2 mo on the diet, systolic blood pressure was reduced with fish protein compared with casein (189.8 ± 10.5 versus 220.7 ± 8.7). Excretion of 6-keto-PGF 1α in urine was negatively correlated with blood pressure. Liver cholesterol and phospholipid concentrations were 1.71- and 1.27-fold lower with fish protein than with casein, respectively. The fish protein diet lowered the 20:4(ω-6) proportion and the ratio of 20:4(ω-6) to 18:2(ω-6) in liver microsomal lipids and phospholipids, which was due to the reduced microsomal Δ6(ω-6) desaturation activity. Dietary protein source did not affect ω-3 fatty acid composition, and this was associated with a similar activation of Δ6(ω-3) desaturation in liver microsomes. The present data indicated a significant blood pressure–lowering effect caused by fish protein, rather than by casein, that modified the fatty acid composition of liver phospholipids and liver microsomal total lipids.