Regulation of lipoprotein lipase synthesis in 3T3-L1 adipocytes by interleukin-1

When fully differentiated 3T3-L1 fatty fibroblasts were exposed to purified, recombinant murine interleukin-1, a dose dependent suppression of lipoprotein lipase activity was observed. The loss of activity reached a maximum of 60-70% of control and appeared to be due to a specific effect on the synthesis of the enzyme as judged by a suppression of the ability to incorporate [35S]methionine into immunoprecipitable lipoprotein lipase. There was no general effect on protein synthesis as determined by radiolabel incorporated into acid precipitable protein, however, after a 17 h exposure of the 3T3-L1 cells to interleukin-1, the synthesis of two proteins (molecular weights, 19,400 and 165,000 daltons) was enhanced several fold. The observed effects on protein synthesis in the adipocytes occur at a concentration of interleukin-1 which is similar to the concentration necessary for the stimulation of [3H]thymidine incorporation into mouse thymocyte DNA. The present study represents the first unequivocal report of the ability of interleukin-1 to regulate protein synthesis in intact cells, specifically adipocytes. Moreover, their results demonstrate the ability of interleukin-1 to regulate metabolism by controlling the synthesis of specific proteins