title: Effects of islet neogenesis-associated protein pentadecapeptide on cell mass and insulin secretion of pancreatic β-cells.
abstract: OBJECTIVE
  To explore the effects of islet neogenesis- associated protein pentadecapeptide (INGAP-PP) on proliferation and secretion function of β-cells.
  
  
  METHODS
  Islets of adult Sprague Dawley rats were isolated by collagenase digestion and treated with 10 μg/ml INGAP-PP, after 12, 24, 48 h, glucose-stimulated insulin secretion (GSIS) and acridine orange/pro pidium iodide (AO/PI) staining were used to detect the secretion function and cell viability. The INS-1 cells were treated with 0, 1, 10, 25, 50, 100, 250, and 500 μg/ml INGAP-PP for 24 or 48 h, MTT cell proliferation assay was adopted to survey the dose-response relationship between INGAP-PP and cell proliferation. The mRNA expression of roliferating cell nuclear antigen (PCNA), Cyclin D1, Cdk4, P27, p38MAPK, and JNK in INS-1 cells were examined by RT-PCR, and the protein expression of PCNA was examined by Western blot. The statistical significance was determined by Student's t-test or one-way analysis of variance.
  
  
  RESULTS
  The insulin secreted by islets and the cell viability were increased by INGAP-PP. MTT indicated a dose-response relationship between INGAP-PP and quantity of INS-1 cells, and treatment for 48 h had a stronger effect on cell proliferation than the 24 h. INGAP-PP up-regulated the mRNA expression of PCNA, Cyclin D1, Cdk4 and downregulated P27, p38MAPK, and JNK. Moreover, the protein expression of PCNA was up-regulated by 45% after INGAPPP exposure for 48 h.
  
  
  CONCLUSIONS
  INGAP-PP increased the insulin secretion, enhanced the proliferation and might reduce apop tosis of β-cells. The mechanism may contribute to the changed expression of some genes related to cell cycle.
authors.affiliation: Department of Endocrinology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, 210029, Jiangsu, China.
authors.forename: M
authors.initials: M
authors.lastname: Zha
authors.forename: M
authors.initials: M
authors.lastname: Zhang
authors.forename: S
authors.initials: S
authors.lastname: Shan
authors.forename: K-F
authors.initials: KF
authors.lastname: Xu
authors.forename: H
authors.initials: H
authors.lastname: Chen
authors.forename: X-Y
authors.initials: XY
authors.lastname: Xu
authors.forename: L
authors.initials: L
authors.lastname: Qian
authors.forename: X
authors.initials: X
authors.lastname: Han
authors.forename: T
authors.initials: T
authors.lastname: Yang
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D002453:Cell Cycle / Q000187:drug effects*; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D016207:Cytokines / Q000494:pharmacology*; D005786:Gene Expression Regulation / Q000187:drug effects; D007004:Hypoglycemic Agents / Q000494:pharmacology; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D050417:Insulin-Secreting Cells / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D007515:Islets of Langerhans / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D020935:MAP Kinase Signaling System / Q000187:drug effects; D008297:Male; D000073718:Pancreatitis-Associated Proteins; D010446:Peptide Fragments / Q000494:pharmacology*; D018809:Proliferating Cell Nuclear Antigen / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D046509:Tissue Culture Techniques
chemical_list: D018797:Cell Cycle Proteins; D016207:Cytokines; D007004:Hypoglycemic Agents; C500438:INGAP peptide; D007328:Insulin; D000073718:Pancreatitis-Associated Proteins; D010446:Peptide Fragments; D018809:Proliferating Cell Nuclear Antigen; C000612141:REG3A protein, human; D012333:RNA, Messenger