The fatty acid pattern of spleen phospholipids and triglycerides was examined in fed or overnight fasted normal rats, streptozotocin-induced diabetic animals (type-1 diabetes) and Goto-Kakizaki rats (type-2 diabetes). In both phospholipids and triglycerides, differences were observed in the relative contribution of several fatty acids, as well as in the ratio between distinct fatty acids, when comparing fed to fasted rats, normal to diabetic animals and male to female Goto-Kakizaki rats. Diabetes increased to a greater extent the C22:6ω3 content of phospholipids in the spleen than in either the liver or the brain. However, the diabetes-induced changes in the C22:6ω3 content of triglycerides was closely comparable in the spleen, liver and brain. These findings suggest that the incorporation of fatty acids into triglycerides is controlled by comparable regulatory factor(s), e.g. insulinemia, in the spleen, liver and brain. In the case of phospholipids, however, an apparent adaptation to diabetic stress was more marked in the spleen than in the liver, and virtually absent in the brain. The proposed dichotomy in the environmental regulation of fatty acid synthesis and incorporation into phospholipids and triglycerides was further supported by distinct diabetes-related changes in the apparent activity of Δ9-desaturase in these two classes of lipids.

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