Glyceride distribution of fatty acids assimilated by adipose tissue

Palmitic acid, stearic acid, oleic acid and linoleic acid assimilated by epididymal fat pads of mice are primarily esterified at the α-positions of triglycerides. A similar glyceride distribution is observed for fatty acids synthesized from acetate or glucose. Increasing the supply of α-glycerylphosphate by glucose addition did not appreciably affect the fatty acid distribution of the saturated fatty acids. In the presence of glucose the distribution of linoleic acid was uniform and oleic was variable. With palmitate, oleate and stearate, tissues from fasted animals demonstrated an increased disproportionality in α-esterification. This trend was only partially reversed by the addition of glucose to the medium. These results indicate at least two modes of incorporation of fatty acids into the triglycerides by adipose tissue. One provides for complete synthesis de novo and the other carries a high degree of specificity toward incorporation at the α-positions.