Supplemental dietary tyrosine in sepsis and acute hemorrhagic shock.

Previous studies showed that dopamine and norepinephrine levels in rat brain are reduced following stress and that rats fed supplemental tyrosine do not exhibit these reductions. We hypothesized that dietary supplementation with tyrosine would enhance resistance to acute hemorrhagic shock and sepsis by increasing substrate (tyrosine) availability for catecholamine synthesis. Rats were fed either a standard rat chow (6.8 g of tyrosine per kilogram of chow), which supports normal growth, fertility, and longevity, or the same chow supplemented with 10 g of tyrosine per kilogram of chow. Seven days later, the rats underwent cecal ligation and perforation while under intraperitoneal pentobarbital anesthesia. There was a significant increase in survival in the tyrosine-supplemented group. Similarly, in another experiment, tyrosine-supplemented rats were able to tolerate acute fulminant hemorrhagic shock better than were nonsupplemented control animals.