Cell experiment:

Fetal rat intestinal cells (FRICs) are collected by enzymatical digestion of whole fetal rat intestines (mixed sex) and cultured overnight in DMEM containing 4.5 g/L glucose, 5% fetal bovine serum, and 40 U/mL penicillin and 40 μg/mL streptomycin in 10 cm plates. Cells are then treated with GLP-2 (10–8 M) or vehicle in low-glucose DMEM with 0.5% FBS for 0.5 to 24 hours[1].

Animal experiment:

Hamsters that undergo intraduodenal catheterization (idc) are allowed 7 days of recovery before jugular vein catheterization. For postprandial experiments, conscious fasted (16 h) hamsters receive a 75 mmol/kg iv bolus of L-NAME. After 10 minutes, baseline blood sample is collected (time 0), followed by an oralgastric gavage of 3 μL Ci [9,10-3H(N)] triolein in 200 μL olive oil. At t=10 minutes, F-127 is given ip (1 g/kg) to inhibit peripheral TG-rich lipoprotein (TRL) catabolism. At t=20 minutes, the hamsters receive ip injections of either PBS or 0.25 mg/kg human GLP-2(1-33). Blood (400 μL) is collected every 30 minutes for 2 hours. Blood is centrifuged at 6000 rpm for 10 minutes at 4℃ to isolate plasma. Radioactivity is assessed using a liquid scintillation counter[2].

GLP-2(1-33) (human) is an enteroendocrine hormone which can bind to the GLP-2 receptor and stimulate the growth of intestinal epithelium.

GLP-2-treated group demonstrates a 518±22% increase (Pin vitro model of the entire intestine. FRIC cultures have previously been established to express a functional GLP-2 receptor (GLP-2R) that displays a cAMP response, as well as enhances IGF-1 mRNA expression and IGF-1 secretion in response to GLP-2 treatment. When incubates with GLP-2 (10–8 M) for 2 hours, IGFBP-4 mRNA expression in the FRIC cultures is also found to be increased, by 40.8±15.2% (P<0.05), compare with vehicle-treated cells[1].

GLP-2 quickly increases apoB48 mass in the TRL fraction of plasma, which is indicative of chylomicron number, and this is blocked by L-NAME. GLP-2 treatment alone increases postprandial TRL-lipids (slope 3.65±0.73×10–3 g/L/min vs 1.63±0.28×10–3 g/L/min, GLP-2 vs control), and this effect is completely mitigated by L-NAME pretreatment (slope 3.67±0.15×10–4 g/L/min). The GLP-2-induced rise in TRL-apoB48 occurres within 30 minutes and precedes the rise in TRL-TG. GLP-2 acutely increases plasma tritium levels (slope, 1.66±0.25×102 dpm/mL/min vs 1.11±0.17×102 dpm/mL/min, GLP-2 vs control)[2].

References:
[1]. Kaori Austin, et al. IGF Binding Protein-4 is Required for the Growth Effects of Glucagon-Like Peptide-2 in Murine Intestine. Endocrinology. 2015 Feb; 156(2): 429-436.
[2]. Hsieh J, et al. Glucagon-Like Peptide 2 (GLP-2) Stimulates Postprandial Chylomicron Production and Postabsorptive Release of Intestinal Triglyceride Storage Pools via Induction of Nitric Oxide Signaling in Male Hamsters and Mice. Endocrinology. 2015 Oct;156(10):3538-47.