Alterations in calcium metabolism in phorbol ester-treated mouse peritoneal macrophages.
Phorbol 12-myristate 13-acetate (PMA)-treated macrophages exhibited a two-fold increase in the rate of 45Ca++ efflux and over a three-fold increase in the size of the exchangeable calcium pool, resulting in almost a seven-fold increase in the slow phase of calcium efflux. The calcium antagonist 8-(N,N-diethylamino) octyl 3,4,5-trimethoxybenzoate hydrochloride (TMB-8) by itself did not affect calcium efflux in macrophages; but abolished the PMA-induced increase in the rate of calcium efflux. The divalent cationphore A23187 increased the rate constant of the fast phase of calcium efflux two-fold when applied alone or when applied with PMA. These effects might be linked to ionophore enhancement and TMB-8 inhibition of PMA-induced macrophage chemotaxis and spreading (previously reported in Cell Calcium 3:503-514 and Cancer Research 43:3385-3391). No change in calcium efflux was observed if cells were exposed to PMA only during the efflux experiment suggesting that a prolonged exposure to PMA is required to elicit changes in calcium flux. Increased 45Ca++ remained in treated cells at each time point perhaps reflecting the PMA-induced increase in exchangeable calcium.
Smith
B M
BM
Warner
W
W
Carchman
R A
RA
D000818:Animals; D001693:Biological Transport, Active; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D005260:Female; D005707:Gallic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D007473:Ion Channels / Q000378:metabolism; D007700:Kinetics; D008264:Macrophages / Q000187:drug effects* / Q000378:metabolism; D051379:Mice; D008813:Mice, Inbred ICR; D010529:Peritoneal Cavity / Q000166:cytology; D010703:Phorbol Esters / Q000494:pharmacology*
D007473:Ion Channels; D010703:Phorbol Esters; D000001:Calcimycin; C006014:8-(N,N-diethylamino)octyl-3,4,5-trimethoxybenzoate; D005707:Gallic Acid; D002118:Calcium