Gut hormones, and short bowel syndrome: The enigmatic role of glucagon-like peptide-2 in the regulation of intestinal adaptation

Table 1 Growth factors as potential stimulators of intestinal adaptation

		Mucosal growth factors and SBS
Growth factor	Amino acids /MW	Main source	GI receptor localization
GLP-2	33 aa/3.8 kDa	Ileal and colonic EE L-cells, pancreatic α cells	GLP-2R; EE cells, myenteric/submucosal neurons of ENS
EGF	53 aa/6.4 kDa	Submandibular gland, duodenal Brunner’s gland, epithelial and Paneth cells	EGFR/HER/ErbB, HER2/Neu/ErbB2, HER3/ErbB3, HER4/ErbB4
KGF (FGF-7)	194 aa/2.5 kDa	Fibroblast-like stromal cells in epithelial tissue	KGFR; a/bFGFR epithelial cells
Hb-EGF	86 aa/22 kDa	Smooth muscle cells	Activate all as listed for the EGFR
GH	191 aa/22 kDa	Liver	CRF type-1, PRL-R
TGF-α	50-53 aa/6.2-6.4 kDa	Epithelial cells	Activate all as listed for the EGFR
NT	13 aa/?	Ileum/colon >> proximal SB, EE N-cells	NTR1
PYY	36 aa/42 kDa	Ileal and colonic EE L-cells	Y1-R; EE cells, myenteric/submucosal neurons of ENS
GRP	14 aa/?	Neuroendocrine cells in the ENS, fibroblasts	GRPR antrum, upper GI tract
CCK	8, 33 aa/39 kDa	Duodenal EE I-cells	CCKA >> CCKB upper GI tissue
			myenteric/submucosal neurons of ENS
Gastrin	17 aa/21 kDa	Gastric antrum G-cells	CCKB >> CCKA
	34 aa/40 kDa	Pancreatic D-cells	upper GI tissue
IGF-I/II	I-70 aa/7.6 kDa,	Proximal SB >> distal, liver,	IGF-IR and IGF-IIR
	II-67 aa/7.4 kDa	Fibroblasts	epithelial cells, glial cells, fibroblasts

Many of these factors include peptide hormones, growth factors, and neurovascular components. SB, small bowel; ENS, enteric nervous system; EE, enteroendocrine; GLP-2, glucagon-like peptide-2; EGF, epidermal growth factor; Hb-EGF, heparin-binding EGF; KGF, keratinocyte growth factor (FGF-7); FGF, fibroblast growth factor; GH, growth hormone; CRF-1, cytokine-related family type-1 (JAK-STAT pathway); PRL, prolactin (subgroup of the CRF-1 superfamily); TGF-α, transforming growth factor-α; NT, neurotensin; PYY, peptide tyrosine tyrosine; GRP, gastrin-releasing peptide; CCK, cholecystokinin; IGF-I/II, insulin-like growth factor I/II.