Substance P and enteroglucagon-like immunoreactivity in argentaffin and argyrophil midgut carcinoid tumours

The presence of serotonin, substance P and enteroglucagon was investigated in 8 argentaffin and argyrophil midgut carcinoid tumours. All tumours were argentaffin and displayed formalin-induced fluorescence indicating a content of serotonin. In addition, all 8 tumours showed substance P immunoreactivity and 7 of them enteroglucagon immunoreactivity. The results indicate that the midgut carcinoid tumours are as a rule multihormonal.