Glucagon-like peptide-1 (GLP-1) and its analog exendin (EX)-4 have been considered to promote β-cell growth and expansion. In the present, study we investigated the effect of GLP-1 on proliferative activity and cell cycle regulation in the pancreatic insulin-secreting β-cell line, INS-1, treated with intermittent high glucose. INS-1 cells were treated with normal glucose (5.5 mmol/l), constant ...

CONTEXT Prolactin is one of the most potent growth stimulating growth hormones of pancreatic beta cells. OBJECTIVE We investigated the role of prolactin on the proliferation of the beta-cell line INS-1. DESIGN In particular, we investigated the involvement of intracellular signal transduction molecules in prolactin-dependent upregulation of INS-1 growth. SETTING The effect of prolactin on...

With a h.p.l.c. system, the inositol mono-, bisand tris-phosphate isomers found in [3H]inositol-labelled GH3 cells were resolved and identified. These cells possess at least ten distinct [3H]inositol-containing substances when acid-soluble extracts are analysed by anion-exchange h.p.l.c. These substances were identified by their co-elution with known inositol phosphate standards and, to a limit...

Ins(1,3,4,5)P4 was able to mobilize the entire Ins(1,4,5)P3-sensitive intracellular Ca2+ store in saponin-permeabilized SH-SY5Y human neuroblastoma cells in a concentration-dependent manner, yielding an EC50 value of 2.05 +/- 0.45 microM, compared with 0.14 +/- 0.03 microM for Ins(1,4,5)P3. However, L-Ins(1,3,4,5)P4 [= D-Ins(1,3,5,6)P4] failed to cause mobilization of intracellular Ca2+ at conc...

background: mdm2 (murine double minute2) is an oncoprotein that inhibits the p53 activity. overexpression of mdm2 gene has been reported in several human tumors. in the present study, we aimed to evaluate the impact of 40-bp insertion/deletion (ins/del) polymorphism on the promoter of mdm2 and susceptibility to breast cancer in a sample of iranian population. methods: this case-control study wa...

L-Type Ca channel blockers inhibit glucose and KCl-stimulated insulin secretion by pancreatic cells. However, the role of the two distinct L-type channels expressed by cells, Cav1.2 and Cav1.3, in this process is not clear. Therefore, we stably transfected INS-1 cells with two mutant channel constructs, Cav1.2DHPi or Cav1.3 DHPi. Whole-cell patch-clamp recordings demonstrated that both mutant c...

Embryonic stem (ES) cells which constitutively express the Pdx-1, Ngn-3, NeuroD1, Nkx2.2, and Nkx6.1 transcription factors were engineered by means of lentiviral vectors, following a multi-step infection procedure to successively generate ES cell lines expressing one, two, and three factors, respectively. Each ES cell line was allowed to differentiate into nestin+/Isl-1+ endocrine precursors, t...

BACKGROUND Blood glucose level continuously fluctuates within a certain range in the human body. In diabetes patients, the extent of such fluctuation is large, despite the strict control of blood glucose. Blood glucose fluctuation has been shown to mediate more adverse effects on vascular endothelial cells and diabetes complications than chronic hyperglycemia, which has been explained as due to...