THE LIPOXYGENASE INHIBITORS OF ARACHIDONI C-ACID OXIDATION INCREASE CYTOSOLIC-FREE CA2-A( AND H+ IN THYMOCYTES AND BLOCK CHANGES OF THESE PARAMETERS INDUCED BY CONCANAVALIN)
Am. Surin et al., THE LIPOXYGENASE INHIBITORS OF ARACHIDONI C-ACID OXIDATION INCREASE CYTOSOLIC-FREE CA2-A( AND H+ IN THYMOCYTES AND BLOCK CHANGES OF THESE PARAMETERS INDUCED BY CONCANAVALIN), Biologiceskie membrany, 9(10-11), 1992, pp. 1034-1038
The lipoxygenase inhibitors of arachidonic acid (AA) oxidation, nordih
ydroguaiaretic acid (NDGA) and gossypol (Gos), at concentrations of 20
muM and 1.2 muM respectively, have been shown to prevent the Ca2+ sig
nal induced by Con A. The lipoxygenase blockers have been demostrated
to induce a cytosolic free calcium concentration ([Ca2+]i) rise compar
able with that of mitogenic lectins, NDGA or Gos mobilized Ca2+ from i
ntracellular stores and enhanced the Ca influx from the extracellular
media. The additive effects of NDGA and Gos suggest that there are ind
ependent pathways of Ca2+ regulation used-by these agents. NDGA and Go
s induced decrease of cytosolic pH (pH(i)) in thymocytes. This effect
was not due to the inhibition of Na+/H+-exchanger because it was manif
est both in sodium-free media and in the presence of ethylisopropylami
loride. NDGA and Gos prevented totally Con A stimulated cytosolic alka
lization. The possible mechanisms of action of NDGA and Gos on the maj
or parameters of cellular ionic homeostasis - [Ca2+]i and pH(i) - are
discussed.