The effect of hypolipidemic drugs WY14643 and DH990, and lysophospholipids on the metabolism of oleate in plants.

The effects of the addition of hypolipidemic drugs and 1-acylglycerolipids on the metabolism of oleate in plants have been studied in vivo and in vitro. Using aged potato slices with [14C]oleate as a precursor, it was found that these drugs markedly inhibited both the incorporation into complex lipids and the desaturation of oleate to linoleate. Moreover, in vitro experiments, carried out with microsomes prepared from developing safflower seeds and [14C]oleate or [14C]oleoyl-CoA as precursors, confirmed the inhibitory effect of the drugs on oleate desaturation, and showed that while WY14643 mainly affected oleoyl thiokinase activity, DH990 exerted its strongest effect on the formation of PL, indicating that the mode of action of these two drugs in safflower microsomes is essentially different. Addition of LPC or LPE stimulated the incorporation of radiolabeled precursor into PC and PE, respectively, as well as the desaturation of oleate to linoleate when [14C]oleoyl-CoA was the precursor. The evidence obtained suggests that oleoyl-PE, as well as oleoyl-PC, should be considered as a possible substrate for oleate desaturation in plants.