The Effect of Somatostatin Analogue SMS 201—995 on Serotonin Levels in the Medium of Primary Carcinoid Cell Cultures

Carcinoid cell cultures were established from primary tumours and liver and mesenteric metastases. The cells continued to produce serotonin for up to 6 months. Cells from different tumours showed different properties. In most wells carcinoid cells grew on a layer of fibroblasts. The tendency to co-culture seemed to be less marked in cells from liver biopsy specimens. The amount of serotonin decreased to 63% 300 min after addition of the somatostatin analogue SMS 201-995 (SMS) to the culture, compared with controls (p0.05; n = 10). This decrease was observed up until 12 days, when SMS was added at each change of medium (p0.005; n = 8). In the first 10 min, however, SMS induced an increase in serotonin concentration (p0.005; n = 11). This effect may be related to other, immediate stimulatory effects of SMS seen in other cell lines originating from neural ridge-derived tissue. We believe it is important to elucidate the properties of individual tumours, as choice of therapy may vary between patients with the same diagnosis. We have described a method to obtain such information within a couple of days, before a definite treatment is selected.