0000000000780299
AUTHOR
Christina Stichnote
Activation of L-arginine transport by protein kinase C in rabbit, rat and mouse alveolar macrophages
1 The role of protein kinase C in controlling L-arginine transport in alveolar macrophages was investigated. 2 L-[3H]Arginine uptake in rabbit alveolar macrophages declined by 80 % after 20 h in culture. 4β-Phorbol 12-myristate 13-acetate (PMA), but not 4α-phorbol 12-myristate 13-acetate (α-PMA), present during 20 h culture, enhanced L-[3H]arginine uptake more than 10-fold. Staurosporine and chelerythrine opposed this effect. 3 L-[3H]Arginine uptake was saturable and blockable by L-lysine. After PMA treatment Vmax was increased more than 5-fold and Km was reduced from 0.65 to 0.32 mM. 4 Time course experiments showed that PMA increased L-[3H]arginine uptake almost maximally within 2 h. This…
Inhibition of nitric oxide synthase abrogates lipopolysaccharides-induced up-regulation of L-arginine uptake in rat alveolar macrophages
It was tested whether the inducible nitric oxide synthase (iNOS) pathway might be involved in lipopolysaccharides-(LPS)-induced up-regulation of L-arginine transport in rat alveolar macrophages (AM). AM were cultured in absence or presence of LPS. Nitrite accumulation was determined in culture media and cells were used to study [3H]-L-arginine uptake or to isolate RNA for RT - PCR. Culture in presence of LPS (1 microg ml(-1), 20 h) caused 11 fold increase of nitrite accumulation and 2.5 fold increase of [3H]-L-arginine uptake. The inducible NO synthase (iNOS) inhibitor 2-amino-5,6-dihydro-6-methyl-4H-1,3-thiazine (AMT) present alone during culture had only marginal effects on [3H]-L-arginin…