Distribution of 5-hydroxytryptamine (5HT) in tissue of a mutant mouse deficient in mast cell (W/Wv). Demonstration of the contribution of mast cells to the 5HT content in various organs.

The content of 5-hydroxytryptamine (5HT) in various tissues of mutant mouse (W/Wv) deficient in mast cells and of control mouse (+/+) was determined by high performance liquid chromatography. The depletion of mast cells in the mutant mouse (W/Wv) was expected to cause a decrease in the 5HT content. In the control mice, 5HT was most densely accumulated in the lung (9.66 +/- 5.23 micrograms/g). Large intestine (6.40 +/- 2.61 micrograms/g) and stomach (6.10 +/- 2.14 micrograms/g) followed the lung in the rating of the 5HT content. The 5HT content of W/Wv mice was only 23.4% and 4.1% that of the control in the stomach (p less than 0.01) and the skin (p less than 0.01), respectively. The results were consistent with the expectation. In other organs (small intestine, caecum, large intestine, brain, lung, blood and salivary gland), the difference between the W/Wv and normal mice was not statistically significant. The difference in the 5HT content of the stomach between the two genotypes was 4.67 micrograms/g and was much larger than the 5HT content (0.49 micrograms/g) of normal mouse skin. With regard to the relatively small number of mast cells present in the stomach, the great difference in the 5HT content in the stomach between the two genotypes cannot be explained by the loss of mast cells. Hence, besides mast cells other cells may contribute to the high 5HT content of the stomach.