The gut incretin glucagon-like peptide-1 (GLP-1) and the intestinotropic hormone - are released from enteroendocrine L cells in response to ingested nutrients. Treatment with an exogenous - analogue increases intestinal villous mass and prevents intestinal injury. Since - is rapidly degraded by dipeptidyl peptidase 4 (DPP4), DPP4 inhibition may be an effective treatment for intestinal ulcers. We measured mRNA expression and DPP enzymatic activity in intestinal segments. Mucosal DPP activity and GLP concentrations were measured after administration of the DPP4 inhibitor sitagliptin (STG). Small intestinal ulcers were induced by indomethacin (IM) injection. STG was given before IM treatment, or orally administered after IM treatment with or without an elemental diet (ED). DPP4 mRNA expression and enzymatic activity were high in the jejunum and ileum. STG dose-dependently suppressed ileal mucosal enzyme activity. Treatment with STG prior to IM reduced small intestinal ulcer scores. Combined treatment with STG and ED accelerated intestinal ulcer healing, accompanied by increased mucosal - concentrations. The reduction of ulcers by ED and STG was reversed by co-administration of the - receptor antagonist. DPP4 inhibition combined with luminal nutrients, which up-regulate mucosal concentrations of -, may be an effective therapy for the treatment of small intestinal ulcers.

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Glucagon-like peptide 2 (-) is an intestinotropic peptide that binds to - receptor (-R), a class-B G protein-coupled receptor. The -R antagonist -(3-33) has relatively high partial agonistic activity, and there are as yet no ideal known potent -R antagonists. We therefore prepared several truncated forms of human - and characterized them by binding and reporter assays to find antagonists more potent than -(3-33). We found that -(11-33) was the most potent orthosteric -R antagonist, with binding activity almost equal to those of - and -(3-33) and weaker intrinsic agonistic activity than -(3-33). -(11-33) retained weak agonistic activity toward human, cynomolgus monkey, dog, and Syrian hamster -Rs. However, it had no agonistic activity toward rat -R. -(11-33) potentiated the agonistic activity of an ago-allosteric modulator of -R, compound 1 (N-[1-(2,5-dichlorothiophen-3-yl)-2-(phenylsulfanyl)ethylidene]hydroxylamine), synergistically toward human -R. In the case of rat -R, -(11-33) decreased the agonistic activity of compound 1, although - and -(3-33) increased this activity additively. These findings suggest that the binding sites of the ago-allosteric modulator and - overlap, at least in rat -R. -(11-33) is a novel, useful tool for analyzing the mode of action of agonists and ago-allosteric modulators of -R.

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Glucagon-like peptide 2 (-) is an intestinotropic peptide that binds to - receptor (- R), a class-B G protein-coupled receptor (GPCR) coupled with Gα_s. Few small-molecule agonists had been reported for class-B GPCRs, but we recently reported the first scaffold compounds of ago-allosteric modulators for human -R. Methyl 2-{[(2Z)-2-(2,5-dichlorothiophen- 3-yl)-2-(hydroxyimino)ethyl]sulfanyl}benzoate (compound 1) and its de-esterified derivative (compound 2) induced placental alkaline phosphatase (PLAP) activity in HEK293 cells overexpressing human -R and PLAP driven by cAMP response element. In this study, we observed that rat, Syrian hamster, and dog -Rs also responded to compounds 1 and 2 in the same reporter system. However, no agonistic activity of the compounds toward mouse -R was detected. Mutagenesis studies showed that mutant human -Rs with Pro392Leu substitution of mouse -R for human -R amino acid residues nullified the PLAP activity of compound 2, although these mutant receptors responded to -. This finding suggests that the Pro392 residue of human -R is essential for the agonistic activity of compound 2.

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Background: Glucagon-like peptide-2 (

-) is a pleiotropic hormone secreted from intestinal L-cells. - is known to improve and maintain intestinal homeostasis, and shows therapeutic efficacy in small and large bowel inflammation. To clarify the relationship between intestinal - dynamics and chemotherapy-induced intestinal injury, we investigated the - dynamics in rat small intestine after administration of either methotrexate or 5-fluorouracil.

Methods: Rat were i.p. injected with either methotrexate (50 mg/kg) or 5-fluorouracil (100 mg/kg). At an appropriate time after the injection, the intestinal tissues were dissected out and frozen rapidly in liquid nitrogen and stored until further analysis. Myeloperoxidase and

- expression and localization were analyzed by immunohistochmical analysis. mRNA expression was analyzed by RT-qPCR.

Results: A single administration of 5-fluorouracil caused intestinal damage in a time-dependent manner up to 72 hrs, whereas methotrexate had almost no effect. At 24 hrs after administration, methotrexate significantly increased mRNA expressions of proglucagon, a precursor of

-, - receptor and insulin-like growth factor-1, an essential factor of the intestinal tropic effects of -. Numbers of anti-- antibody positive cells in the intestine were also increased by methotrexate administration. On the other hand, 5-fluorouracil significantly reduced these mRNA expressions as well as the numbers of anti-- antibody positive cells. Methotrexate and 5-fluorouracil slightly and significantly increased mRNA expression of dipeptidyl peptidase-4 which inactivates -, respectively.

Conclusion: Methotrexate accelerated intestinal

- dynamics without obvious intestinal injury, whereas 5-fluorouracil inhibited the dynamics with serious injury. These results suggest that the effect of anti-cancer drugs on intestinal - dynamics is closely correlates with chemotherapy-induced intestinal injury. Methotrexate-induced upregulation of intestinal - dynamics may contribute to counteract the intestinal damage by methotrexate.

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Brain-gut peptides play important roles in the appetite regulatory system in mammals. Glucagon-like peptide (GLP)-1, -, and oxyntomodulin (OXM) are processed from the same precursor, proglucagon, in both brain and intestines in mammals and birds. We previously showed that intracerebroventricular administration of these three peptides significantly suppressed food intake in chicks. However, peripheral roles of chicken - have not yet been investigated, although - plays important roles both in central and peripheral regulation of food intake in mammals. The aim of this study is to investigate whether - functions as an anorexigenic peptide in both brain and peripheral circulation in chicks. Intracerebroventricular administration of - significantly suppressed food intake in chicks. Twenty-four hours of fasting significantly decreased the mRNA level of proglucagon in the medulla oblongata of chicks. These results suggest that - functions as anorexigenic peptides in the central nervous system in chicks. In addition, intravenous administration of - significantly suppressed food intake in chicks. Lines of evidence suggest that dietary nutrients stimulate the secretion of - from L cells in the small intestine in chickens. These findings suggest that - functions as both central and peripheral anorexigenic signals in chicks.

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The aim of this study was to clarify the relationship between chemotherapy-induced mucositis and endogenous glucagon-like peptide-2 (

-) dynamics in the small intestine following treatment with either methotrexate or 5-fluorouracil. Rats were injected intraperitoneally with a single dose of either 50 mg/kg methotrexate or 100 mg/kg 5-fluorouracil. At 24 and 72 h after drug administration, ileal tissues and plasma were used to investigate - dynamics. Administration of methotrexate caused moderate but not significant intestinal injury within 72 h, while administration of 5-fluorouracil caused severe injury in a time-dependent manner. Methotrexate significantly increased proglucagon mRNA expression and the number of anti-- antibody-positive cells in the ileal tissue at 24 h after administration. Methotrexate also significantly induced - receptor, insulin-like growth factor-1 (IGF-1), and transforming growth factor-β2 (TGF-β2) mRNA expression in ileal tissue. In contrast, 5-fluorouracil significantly inhibited proglucagon, - receptor, IGF-1, and TGF-β2 mRNA expression as well as the number of anti-- antibody-positive cells. Methotrexate slightly increased dipeptidyl peptidase IV (DPP-4) mRNA expression, whereas 5-fluorouracil significantly increased DPP-4 mRNA expression. These results suggest that potentiation of endogenous - dynamics by methotrexate is associated with a mechanism that preserves gastrointestinal mucosal integrity at a moderate level.

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Glucagon-like peptide 2 (-) is a potent intestinal epithelium-specific growth factor that has been shown to reduce the severity of inflammatory disorders of the intestine in rodent models. We examined whether a relationship exists between plasma level of - and the degree of intestinal injury induced by chemotherapeutic agents in the rat. Methotrexate (MTX) was administrated orally for 6 consecutive days at doses of 1.25, 2.5, and 5.0 mg/kg body weight per day. Mucosal samples of rat duodenum, jejunum, and ileum were used for assessment of mucosal weight, DNA and protein content. Plasma - levels were measured on day 8. MTX significantly reduced body weight. The values of all indices tended to decrease in all segments with increases in MTX dose. Plasma - levels were significantly higher in the MTX 2.5 mg/kg/d group (p<0.05) and the MTX 5.0 mg/kg/d group (p<0.01) than in the control group. Correlations were found between plasma - levels and mucosal weight, DNA and protein content. We concluded that plasma - levels reflect the degree of intestinal injury following MTX administration in this preclinical model.

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We investigated the effects of endogenous glucagon-like peptide-2 (-) on the development of intestinal mucosa in weanling rats. Three-week-old male weanling Sprague-Dawley rats were administered either anti-- or normal rabbit serum every other day for 2 weeks. We then measured length, weight, and bromodeoxyuridine incorporation in the intestine on day 13 following the first injection. Administration of anti-- serum significantly inhibited both epithelial proliferation in the distal ileum and elongation of the small intestine. These results suggest that intrinsic - contributes to the growth of the small intestine during the weanling period.

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Lipopolysaccharide (LPS; endotoxin) is a lipophilic pathogenic factor derived from gut Gram-negative bacteria. Increased serum LPS concentrations are associated with the metabolic syndrome, termed metabolic endotoxemia. Since the origin of circulating LPS is the gut lumen, we studied the mechanisms of LPS transport across the gut mucosa, hypothesizing that transport occurs via known lipid uptake pathways. Since glucagon-like peptide-2 (

-) reduces intestinal solute permeability but enhances fat absorption, we also hypothesized that - affects LPS transport during fat absorption. We thus examined LPS transport mechanisms and the effect of exogenous - on LPS transport in intact intestinal tissues in vitro and in vivo.

FITC-LPS absorption in vivo was quantitated by simultaneously measuring the appearance of FITC-LPS into the portal vein (PV) and the mesenteric lymph, with or without luminal oleic acid (30 mM) with taurocholate (OA/TCA). We also examined LPS transport from mucosal to serosal solution (m-to-s) in Ussing chambered muscle-stripped intestinal tissues, the latter measured by the Limulus amebocyte lysate test.

Bolus intraduodenal infusion of FITC-LPS (50 μg/ml) with OA/TCA rapidly increased FITC-LPS appearance into PV, followed by a gradual increase of FITC into the lymph, whereas FITC-LPS appearance into PV or lymph was not observed without OA/TCA. In Ussing chambered jejunum, luminally-applied LPS (10 μg/ml) rapidly appeared in the serosal solution with luminal OA/TCA, whereas LPS alone or LPS+TCA was not transported. OA/TCA-induced LPS m-to-s transport in the jejunum was inhibited by luminal pretreatment with the lipid raft inhibitor methyl-β-cyclodextrin and the CD36 inhibitor sulfosuccinimidyl oleate, but was enhanced by pretreatment with serosal carbachol and luminal application of the competitive alkaline phosphatase inhibitor glycerol phosphate. Pretreatment with serosal

- (100 nM) with a dipeptidyl peptidase-4 inhibitor NVP728 (10 μM) reduced OA/TCA-induced LPS transport, whereas carbachol-induced LPS transport was not affected.

These results suggest that luminal LPS crosses the gut barrier physiologically during fat absorption via lipid raft- and CD36-mediated transport mechanisms, similar to chylomicron transport, and possibly through emptied goblet cells. By reducing lipid raft-, CD36-, and chylomicron-mediated LPS transport,

- treatment may be a novel therapy for metabolic endotoxemia.

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An antigen retrieval method for immunohistochemical staining of glucagon-like peptide ()--immunoreactive cells was investigated in the chicken small intestine. --immunoreactive cells were observed as open-typed endocrine cells in the villous epithelium and crypts on both antigen retrieval agent-treated and untreated preparations. No obvious differences were detected in morphological features of --immunoreactive cells between treated and untreated preparations. The frequencies of occurrence of --immunoreactive cells, however, were significantly different in treated and untreated preparations: in the proximal and distal regions of jejunum and ileum obtained from untreated preparations, the frequencies of occurrence were 0.5 ± 0.2, 0.7 ± 0.1, 0.9 ± 0.2 and 1.5 ± 0.3, respectively (cell numbers per mucosal area: cells/mm², mean ± SD), whereas those from treated sections were 14.7 ± 2.3, 19.8 ± 2.3, 23.5 ± 4.7 and 34.6 ± 4.9 cells/mm², respectively. These data indicate that this antigen retrieval method is able to make immunoreactive - available for detection and that - may act as one of the common hormones secreted by L cells in the chicken small intestine.

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症例は10歳男児，回腸・結腸欠損型の短腸で出生し日齢1に人工肛門を造設された．栄養管理が必要になったため，2歳時から中心静脈カテーテル（central venous catheter: CVC）を留置し経口摂取に加え，在宅中心静脈栄養を開始した．何度かカテーテル関連血流感染症（catheter related blood stream infection; CRBSI）を起こし，CVCの入れ替えを行った．2021年に短腸症候群治療薬であるGlucagon-like peptide-2（

-）アナログ製剤のテデュグルチドが保険収載されたため，当院でも投与を開始し1年以上が経過した．内視鏡検査で絨毛の延長が視認でき，便性状が改善した．身長や体重を維持しつつ静脈栄養の依存軽減が可能で，CRBSI発生の頻度が減少した．有害事象として腹痛とストーマパウチ内への排ガスの増加を認めたが，時間経過とともに改善した．人工肛門を造設している短腸症候群患児にテデュグルチドの効果を認めており，経過を報告する．

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  We examined the effects of Hachimi-jio-gan (HJ) on the small intestinal function in streptozotocin (STZ)-induced diabetic rats. The rats had free access to pellets containing 1% HJ extract powder for 4 weeks after STZ administration. The intestinal disaccharidase (sucrase and maltase) activity was elevated in STZ-treated rats compared with control rats, whereas it was significantly reduced by HJ administration. This suggested that HJ suppresses or delays monosaccharide production in the small intestinal epithelium. In addition, the intestinal mucosal weights and DNA contents that were significantly increased in the STZ-treated rats were restrained to the control level by HJ treatment. Simultaneously, we examined the changes in the plasma levels of glucagon-like peptide 2 (-), which is a trophic factor specific for the intestine. The plasma - levels significantly increased in the STZ-treated rats, whereas HJ decreased the plasma - levels. Thus intestinal mucosal weights and DNA contents correlated with plasma - levels in diabetes-associated bowel growth. These results suggest that HJ may normalize or suppress the small intestinal disaccharidase activity and the epithelial cell proliferation mediated by - in the animal model rats.

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  シトルリンは肝の尿素回路の中間産物として良く知られているが，生体内で遊離した状態で存在するものはそのほとんどが小腸細胞で生成されたものである．シトルリンは門脈血流に乗って肝臓に運ばれるが，そのまま通り抜け腎臓でアルギニンに変換されて多彩な生理機能を発揮する．アルギニンは小児の成長にとっても欠くことのできないアミノ酸であり，小腸はシトルリンを絶え間なく産生することによってアルギニンの安定的な供給を担っている．それゆえ血漿シトルリン濃度は小腸の機能的なサイズを反映するマーカーとして注目され，短腸症候群における静脈栄養離脱の指標となるのみならず，絨毛萎縮を伴う小腸疾患，抗がん剤治療や放射線治療による小腸粘膜傷害，小腸移植後の拒絶反応，新生児壊死性腸炎からの回復過程などのマーカーとして利活用されている．最近では，小児短腸症候群に対する腸管延長術のひとつである serial transverse enteroplasty の術後や，- アナログ製剤の投与によって血漿シトルリン濃度も上昇することが報告されている．

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This review focuses on the anti-dementia and antidepressant-like effects of peptides including glucagon-like peptide (GLP)-1,

-, neuromedin U (NmU), and oxytocin, and the intranasal delivery of these peptides to the brain. Intracerebroventricularly administered GLP-1, NmU, and oxytocin improved impairment of learning and memory in mice treated with lipopolysaccharide or β-amyloid protein. GLP-1 also improved impairment of learning and memory in juvenile diabetes model rats. On the other hand, - exhibited antidepressant-like effects in mice during the forced-swim test, which were associated with 5-HT_1A, α₂, β₁, and D₂ receptors. - also exerted antidepressant-like effects in adrenocorticotropic hormone (ACTH)-treated mice through restoration of the hypothalamic-pituitary-adrenal-axis and neurogenesis in the subgranular zone of the dentate gyrus. Because intracerebroventricular administration is invasive and the peptides are unable to penetrate the blood-brain barrier, we introduced our new method of intranasal administration to deliver the peptides to the brain. We prepared a - derivative containing cell-penetrating peptides (CPPs) and a penetration accelerating sequence (PAS). Intranasally administered PAS-CPPs-- was distributed throughout the brain, and exhibited antidepressant-like effects in both naive and ACTH-treated mice. The derivatives of GLP-1, NmU, and oxytocin with the PAS and CPPs were also distributed throughout the brain after intranasal administration, and improved impairment of learning and memory. We confirmed that our peptide derivatives were effectively delivered into the brain by intranasal administration. As such, these derivatives may be useful for the clinical treatment of psychiatric and neurological diseases.

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