Table 3.

Systemic and duodenal serotonin metabolism.

24 h urine	Butyrate, n = 12			FMT, n = 12			∗P
	Before	After	P	Before	After	P
5-HIAA per 24h, μmol/l	30 [18–42]	29 [17–34]	0.27	42 [31–74]	33 [25–46]	0.35	0.93
duodenal EC cells, cells/100 uM2	1.2 [1.0–1.7]	1.1 [1.0–1.6]	1.00	1.1 [0.9–1.6]	1.2 [0.9–1.4]	1.00	0.90
Small intestinal biopsy	n = 7			n = 7
TPH1 expression, relative to 36B4	0.0027 [0.0013–0.0035]	0.0037 [0.0013–0.0135]	0.49	0.0044 [0.0017–0.0272]	0.0016 [0.0010–0.0053]	0.17	0.22

Data are expressed as median [range]. ∗p = change over time between groups. 5-HIAA = 5-hydroxyindoleacetic acid (24 h urine), EC = enterochromaffin, TPH1 = tryptophan hydroxylase 1 (qPCR duodenal cells).