Effect of Temperature on Fatty Acid Metabolism in Dissociated Cell Cultures of Developing Brain

Abstract

ExtractThe effect of hypothermia on the incorporation and metabolism of essential fatty acids (linoleic and linolenic acids) by dissociated cell cultures of developing brain was examined. When the ambient temperature was reduced to 30°, chain elongation of linolenic acid (1 8 : 3) to 20 : 3, and elongation of 20 : 5 to 22 : 5 was slowed. Desaturation of 20: 3 to 20 :4 and 20: 5 remained unaffected even a t 22'. Incorporation of (1-14C)linolenic acid into the fraction containing ethanolamine phosphoglycerides and ethanolamine plasmalogens (EPG) was significantly reduced by hypothermia, whereas labeling of choline phosphoglycerides (CPG) was greater at 30' and 22' than at 37', and fell only slightly at 15'. These observations suggest that EPG labeling depends on the availability of the higher polyunsaturated fatty acids (22:5 and 22 : 6), whereas CPG labeling is nonspecific. Because ethanolamine plasmalogens are major myelin constituents, the importance of hypothermia in inducing a deficiency of the higher polyunsaturated fatty acids within the developing nervous system, and thus interfering with the biosynthesis of EPG and indirectly with membrane deposition, needs to be clarified. SpeculationThese studies suggest that hypothermia may induce a deficiency of the higher polyunsaturated fatty acids in the developing nervous system, which, in turn, could induce a defect in the formation of cell membranes. Increases in the concentration of essential fatty acids for formulas intended for low birth weight infants might compensate for this relative deficiency.