Dc. Ramirez et al., Biphasic effect of cadmium in non-cytotoxic conditions on the secretion ofnitric oxide from peritoneal macrophages, TOXICOLOGY, 139(1-2), 1999, pp. 167-177
The effects of cadmium (Cd) in non-cytotoxic conditions on the nitric oxide
(NO) production in peritoneal macrophages (pM) were studied. Peritoneal ma
crophages from Balb/c mice were incubated over 18 h with 5, 10, 20, or 25 m
u M Cd2+ (as CdCl2 21:2 H2O) in the culture medium. Concentrations of 20 mu
M Cd2+ and over had cytotoxic effects, measured by MTT assay. Cell viabili
ty with 10 mu M Cd2+ in the medium was above 90% after 18 h of incubation,
and above 80% after 72 h. At this same Cd2+ concentration, NO production in
creased from 6 to 18 h. At 24 h production decreased but was still above co
ntrol levels. At 48 h production NO was near control levels, and continued
to decrease until the end of the experiment (72 h). NO levels produced with
Cd2+ concentrations of 5, 10 and 20 mu M in the medium were above the cont
rol at 18 h. NO production and lipoperoxidation increased simultaneously af
ter 18 h with 10 mu M of Cd in the medium. Amounts of inducible nitric oxid
e synthase (iNOS) protein and iNOS activity also increased. At a concentrat
ion of 10 mu M Cd has a biphasic effect on NO production over time. (C) 199
9 Elsevier Science Ireland Ltd. All rights reserved.