Effect fo ecdysone on incorporation of C-14-leucine into hepatic protein in vitro.

Abstract

Previous studies(1) indicated that ecdysone, the growth and metamorphosis hormone of insects, may have an effect on mammalian cells also, even though no material yielding a positive bioassay was obtained from human tissues when methods of extraction yielding positive results in insects were used(2). Growth of mammalian cells in tissue culture was inhibited by the hormone(3,4), and a few regressions of sarcoma 180 occurred after injection of ecdysone. In a continuation of these studies, active hormone was added to the fraction of mammalian (murine) liver obtained from centrifugation of homogenates at 14000 × g, and results were compared to samples without the hormone. DL-leucine labeled in position one with C14 was added, and amount of incorporation into protein from zero time for a period of 30 minutes was determined by plating the insoluble material precipitated by trichloracetic acid and counting in the proportional range(5,6,7). (Removal of sources of energy from the system resulted in failure of synth...