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In intestinal cells, arginine (Arg) is 1 of the 2 most potent amino acid activators of [p70.sup.s6k], a key regulator of 5'-terminal oligopyrimidine mRNA translation, a necessary condition for increased cell migration. To investigate the mechanism of response to Arg, we used the rat crypt cell line cdx2-transformed IEC-6 cells (cdx2-IEC) and measured cell migration, immunocytochemical analysis of [p70.sup.s6k] activation in response to Arg, and production of nitric oxide (NO). When treated with Arg, cdx2-IEC increased in phosphorylation on Thr-389 of [p70.sup.s6k] ([pp70.sup.s6k]) compared with control (P < 0.01). Phospho-Thr-421/Ser-424-[p70.sup.s6k] was located in the nucleus shortly after Arg treatment. Arg enhanced [pp70.sup.s6k], cell migration (55% wound coverage), and NO production. In comparison, the branched-chain amino acid leucine (Leu) activated [pp70.sup.s6k], was a weaker stimulator of migration (23% coverage), and did not increase NO. A total of 25 [micro]mol/L DETA-NONOate (DETA/NO) did not significantly enhance phosphorylation of [p70.sup.s6k] but enhanced the rate of cell migration by ~25%. Wound coverage with Leu plus DETA/NO (25 [mu]mol/L) was greater than coverage with DETA/NO alone (P < 0.01). These and our previous studies lead to a model in which Arg must stimulate both [pp70.sup.s6k] (in the nucleus) and NO release to enhance intestinal epithelial cell migration, which may be relevant to diseases that involve intestinal villous injury.

The mechanisms through which moderate wine consumption reduces ischemic cardiovascular events are not yet fully unraveled. Grape extracts or a mixture of the polyphenols contained in wine were previously shown to increase nitric oxide (NO); however, little information is available on the effect of resveratrol, one of the main polyphenols of wine, on platelet NO production. We assessed the effects of resveratrol, at the concentrations attainable after moderate wine intake, on platelet NO production and the mechanism of this activity. Twenty healthy volunteers were studied before and after 15 d of controlled white or red wine intake (300 mL/d). After wine intake, plasma resveratrol and the release of NO by stimulated platelets increased significantly. Resveratrol, at the concentrations detected in plasma after wine intake, was incubated in vitro with washed platelets and several variables related to NO production and to signal transduction were measured. Resveratrol in vitro enhanced significantly the production of NO by stimulated platelets, the activity of platelet NO synthase (NOS), phosphorylation of protein kinase B, an activator of the endothelial NOS (eNOS), and phosphorylation of vasodilator-activated protein (VASP), an expression of the biologic activity of NO in platelets. Simultaneously, we observed decreased phosphorylation of P38 mitogen-activated protein kinase (p38MAPK), a proinflammatory pathway in human platelets, a reduction of the activity of NADPH oxidase, a major source of reactive oxygen species (ROS) and of the generation of [O.sub.2.sup.-] radicals, as detected by cytochrome C reduction. In conclusion, resveratrol, at concentrations attainable after moderate wine intake, activates platelet eNOS and in this way blunts the proinflammatory pathway linked to p38MAPK, thus inhibiting ROS production and ultimately platelet function. This activity may contribute to the beneficial effects of moderate wine intake on ischemic cardiovascular disease.