Diabetes-induced and age-related changes in fatty acid proportions of plasma lipids in rats.
Diabetes-induced and age-related proportional changes in plasma fatty acids of triglycerides (TG), phospholipids (PL), and cholesteryl esters (CE) were investigated using streptozotocin-induced diabetic and control rats. Among n-6 fatty acids from diabetic rat plasma, increased proportions of 18:2n-6 and 20:3n-6 in all three lipid classes and of 18:3n-6 in PL at 1-3 months old and in TG at 3-5 months old were observed. The proportions of 20:4n-6 decreased in both PL and CE, but were unchanged in diabetic TG. Among the n-3 fatty acids, in the early stage, diabetes caused increases in the proportions of 18:3n-3 in PL and CE and of 20:5n-3 and 22:6n-3 in TG, while 22:5n-3 was decreased later in the disease course. These results suggest reduced delta 5-desaturase activities on 20:3n-6 but not on 20:4n-3, while delta 6-desaturase activity on 18:2n-6 was essentially unaffected. Furthermore, the reduction in delta 9-desaturase activity in diabetic rats may well explain the decreases in the proportions of 16:1n-7 and 18:1n-7. However, the proportion of 18:1n-9, another product of delta 9-desaturase, was significantly increased in CE and PL as compared to the controls. Thus, there was a discrepancy between our results and those of earlier studies with respect to the n-9, n-6, and n-3 fatty acid proportions of plasma lipids in diabetic rats. We also investigated age-related changes in the proportions of plasma fatty acids. Although rather small, age-related changes were evident in both diabetic and control rats.
Nishida
S
S
Department of Biochemistry, Nihon University School of Medicine, Tokyo Japan.
Kanno
T
T
Nakagawa
S
S
D000367:Age Factors; D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D002788:Cholesterol Esters / Q000097:blood; D003921:Diabetes Mellitus, Experimental / Q000503:physiopathology*; D044943:Fatty Acid Desaturases / Q000378:metabolism; D005227:Fatty Acids / Q000097:blood*; D006442:Glycated Hemoglobin / Q000032:analysis; D008297:Male; D010743:Phospholipids / Q000097:blood; D051381:Rats; D017208:Rats, Wistar; D014280:Triglycerides / Q000097:blood
D001786:Blood Glucose; D002788:Cholesterol Esters; D044943:Fatty Acid Desaturases; D005227:Fatty Acids; D006442:Glycated Hemoglobin; D010743:Phospholipids; D014280:Triglycerides