INFLUENCE OF MELATONIN ON CHICK SKELETAL-MUSCLE CELL-GROWTH

Melatonin as a highly lipophilic compound readily enters all subcellul ar compartments and acts by various mechanisms. Tn the present study, we investigated the effects of different concentrations of melatonin i n medium (physiological and supraphysiological doses) at two treatment times (48 and 120 hr) on growth and changes of growth parameters of c ultured chick embryonic skeletal muscle cells. The physiological doses of melatonin (100 pg to 10 ng/ml of medium) stimulated proliferation of cells and raised DNA, RNA protein contents and an incorporation of [H-3]leucine into cell protein after 48 hr of treatment. The prolongat ion of exposure to melatonin in the physiological dose to 120 hr or an increase of melatonin dose to a supraphysiological one evoked the inh ibition of cell growth and proliferation by decreasing the number of c ells and the amount of labeled leucine incorporated into cell protein. Results demonstrate that melatonin's action in these cells is time an d dose dependent. (C) 1997 Elsevier Science Inc.