MATERNAL LOW-PROTEIN DIET IN RATS PROGRAMS FATTY-ACID DESATURASE ACTIVITIES IN THE OFFSPRING

Numerous studies show an association between poor fetal growth and adu lt insulin resistance. Recent studies have shown relation between the long chain polyunsaturated fatty acid composition of skeletal muscle m embranes and insulin sensitivity. More detailed analysis has indicated that the activity of Delta 5 desaturase is inversely correlated to in sulin resistance. The amount of docosahexaenoic acid (C22,6n3) is also thought to play a part in determining insulin sensitivity. The purpos e of this study was to test the hypothesis that early growth retardati on in the fat, as a result of maternal protein restriction, would lead to alterations in desaturase activities similar to those observed in human insulin resistance. There were no differences in phospholipid fa tty acid composition in liver or muscle from control and low protein r ats. In both muscle and liver the ratio of docosahexaenoic acid to doc osapentaenoic acid was, however, reduced in low protein offspring. Dir ect measurement of Delta 5 desaturase activity in hepatic microsomes s howed a reduction (p < 0.03) in the low protein offspring which was ne gatively corrrelated (r = -0.855) with fasting plasma insulin. No corr elation was observed in controls. These results show that it is possib le to programme the activity of key enzymes involved in the desaturati on of long chain polyunsaturated fatty acids. This is possibly a mecha nism linking fetal growth retardation to insulin resistance.