title: Phosphate accumulation by muscle in vitro and the influence of vitamin D3 metabolites.
abstract: Phosphate accumulation by muscle in vitro and the effects of vitamin D3 metabolites thereupon were studied in cultures of chick embryo skeletal muscle myoblasts and intact chick soleus muscles. A significant proportion of phosphate accumulation by the cells was Na+-dependent, saturable with respect to phosphate, energy-dependent and inhibited by ouabain and arsenate, in agreement with the operation of a Na+-phosphate cotransport system in the muscle cell plasma membrane as has been described for intestine and kidney. This was further supported by the demonstration of substrate-saturable phosphate uptake in sarcolemma vesicles isolated from chick skeletal muscle. Preincubation of myoblast and soleus muscle cultures with physiological levels of 25-hydroxy-vitamin D3 resulted in a significant stimulation of phosphate accumulation by cultures. 1,25-dihydroxy-vitamin D3 had no effects on the differentiated tissue whereas it markedly increased phosphate accumulation by embryonic muscle cells. In addition, it could be shown that 25-hydroxy-vitamin D3 affects the Na+-linked component of cell phosphate uptake through a mechanism dependent on de novo protein synthesis.
mesh_terms: D015650:24,25-Dihydroxyvitamin D 3; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002112:Calcifediol / Q000494:pharmacology*; D002117:Calcitriol / Q000494:pharmacology*; D002478:Cells, Cultured; D002645:Chickens; D004100:Dihydroxycholecalciferols / Q000494:pharmacology*; D007700:Kinetics; D009132:Muscles / Q000187:drug effects / Q000378:metabolism*; D010710:Phosphates / Q000378:metabolism*; D012964:Sodium / Q000494:pharmacology; D014808:Vitamin D Deficiency / Q000378:metabolism
chemical_list: D004100:Dihydroxycholecalciferols; D010710:Phosphates; D015650:24,25-Dihydroxyvitamin D 3; D012964:Sodium; D002117:Calcitriol; D002112:Calcifediol