ARACHIDONIC-ACID AND PROTEIN-SYNTHESIS INHIBITOR ACT SYNERGISTICALLY TO SUPPRESS INSULIN-STIMULATED GLUCOSE-TRANSPORT IN 3T3-L1 ADIPOCYTES

The effect of arachidonic acid (AA) on insulin-stimulated glucose tran sport by 3T3-L1 adipocytes was examined in the presence of cycloheximi de. We found that AA acted synergistically with cycloheximide to suppr ess insulin-stimulated glucose transport, although it alone was withou t effect. Similar phenomena were observed while protein synthesis inhi bitors other than cycloheximide were employed. Immunoblot analysis ind icated that the increase in plasma membranes of the insulin-regulated glucose transporter (GLUT4) in response to insulin was decreased in ce lls pretreated with cycloheximide for a prolonged time, while total am ount of GLUT4 was not altered. Simultaneous presence of AA with cycloh eximide had no further effect on the amount of GLUT4 in either total o r plasma membranes. Thus the present study suggests that AA in the pre sence of a protein synthesis inhibitor seems to decrease the intrinsic activity of GLUT4.