Effect of variation in endogenous levels of ascorbic acid on the in vitro immunological release of histamine and slow reacting substance of anaphylaxis from actively sensitized guinea-pig lung fragments.

1. The in vitro immunological release of histamine and slow reacting substance of anaphylaxis (SRS-A) from actively sensitized guinea-pig lung fragments was greatly reduced when the animals were maintained on an ascorbic acid-deficient diet. Excessive dietary levels of ascorbic acid did not increase mediator release above normal levels. 2. Restoration of ascorbic acid in the diet of scorbutic guinea-pigs restored in vitro immunological histamine to normal levels. 3. Variation in dietary levels of ascorbic acid had no effect on lung histamine content. 4. The lung ascorbic acid content was proportional to the dietary intake. Approximately 60% of the total lung ascorbic acid was removed by the process of chopping and washing of the tissue. This relationship was independent of dietary intake. 5. The results indicate that the immunological release of mediators of inflammation from guinea-pig lung is dependent on adequate endogenous levels of ascorbic acid.