Phenylephrine synchronizes protein synthesis in the culture of hepatocytes

Published data indicate that 1-3 mu M adrenomimetic phenylephrine increases the concentration of calcium ions in the cytoplasm of cultured hepatocytes . We studied low-density cultures exhibiting no protein synthesis rhythm in the fresh medium and demonstrated that a 2 min action of 2 mu M phenylephr ine induces protein synthesis rhythm, i.e., synchronizes the synthesis osci llations in hepatocytes. A similar effect was observed for a selective inhi bitor of the reticulum calcium pump, di-tert-butyl-benzohydroquinone, that increases the cytoplasm concentration of calcium ions by a receptor-indepen dent mechanism. A calcium antagonist imipramine obviated the synchronizatio n effect of phenylephrine. We propose that short-term changes in the cytopl asm concentration of calcium ions covering the whole cell population are am ong intracellular mechanisms of protein synthesis synchronization in hepato cytes in vitro.