Aims/hypothesis: First-phase insulin release and coordinated insulin pulsatility are disturbed in Type 2 diabetes. The present study was undertaken to explore a possible influence of the oral prandial glucose regulator, repaglinide, on first-phase insulin secretion and high-frequency insulin pulsatility in Type 2 diabetes.
Methods: We examined 10 patients with Type 2 diabetes in a double-blind placebo-controlled, cross-over design. The participants were treated for 6 weeks with either repaglinide [2-9 mg/day (average 5.9 mg)] or placebo in random order. At the end of each treatment period, first-phase insulin secretion was measured. Entrainment of insulin secretion was assessed utilizing 1-min glucose bolus exposure (6 mg/kg body weight every 10 min) for 60 min during (A) baseline conditions, i.e. 12 h after the last repaglinide/placebo administration, and (B) 30 min after an oral dose of 0.5 mg repaglinide/placebo with subsequent application of time-series analyses.
Results: Postprandial (2-h) blood glucose was significantly reduced by repaglinide after 5 weeks of treatment (P < 0.001). The fall in HbA(1c) did not reach statistical significance (P = 0.07). AUC(ins,0-12 min) during the first-phase insulin secretion test was enhanced (P < 0.05). In addition, glucose entrained insulin secretory burst mass and amplitude increased markedly (burst mass: repaglinide, 44.4 +/- 6.0 pmol/l/pulse vs. placebo, 31.4 +/- 3.3 pmol/l/pulse, P < 0.05; burst amplitude: repaglinide, 17.7 +/- 2.4 pmol/l/min vs. placebo, 12.6 +/- 1.3 pmol/l/min, P < 0.05) while basal insulin (non-pulsatile) secretion was unaltered. After acute repaglinide exposure (0.5 mg) basal insulin secretion increased significantly (P < 0.05). Neither acute nor chronic repaglinide administration influenced frequency or regularity of insulin pulses during entrainment.
Conclusion/interpretation: Repaglinide augments first-phase insulin secretion as well as high-frequency insulin secretory burst mass and amplitude during glucose entrainment in patients with Type 2 diabetes, while regularity of the insulin release process was unaltered.
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http://dx.doi.org/10.1111/j.1464-5491.2005.01652.x | DOI Listing |
J Biol Chem
January 2025
Laboratory of Immunogenetics, Pennington Biomedical Research Center, Baton Rouge, LA, 70808, USA; Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803, USA. Electronic address:
Pancreatic islet β-cells express the Cpt1a gene, which encodes the enzyme carnitine palmitoyltransferase 1A (CPT1A), an enzyme that facilitates entry of long chain fatty acids into the mitochondria. Because fatty acids are required for glucose-stimulated insulin secretion, we tested the hypothesis that CPT1A is essential to support islet β-cell function and mass. In this study, we describe genetic deletion of Cpt1a in pancreatic tissue (Cpt1a) using C57BL/6J mice.
View Article and Find Full Text PDFEndocrinol Metab (Seoul)
January 2025
Division of Endocrinology and Metabolism, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, Korea.
In East Asians, type 2 diabetes mellitus (T2DM) is primarily characterized by significant defects in insulin secretion and comparatively low insulin resistance. Recently, the prevalence of T2DM has rapidly increased in East Asian countries, including Korea, occurring concurrently with rising obesity rates. This trend has led to an increase in the average body mass index among East Asian T2DM patients, highlighting the influence of insulin resistance in the development of T2DM within this group.
View Article and Find Full Text PDFBiosci Biotechnol Biochem
January 2025
Department of Agricultural Science, Graduate School of Sustainability Science.
FMRFamide-like peptides (FLPs) and their receptors FMRFamide-related peptide receptors (FRPRs) are widely conserved in free-living and parasitic nematodes. Herein, we identified FRPR-1 as a of FLP-1 receptor candidate involved in larval development and diapause in the model nematode Caenorhabditis elegans. Our molecular genetic study, supported by in silico research, revealed the following: 1) frpr-1 loss-of-function completely suppresses the promotion of larval diapause caused by flp-1 overexpression; 2) AlphaFold2 analysis revealed the binding of FLP-1 to FRPR-1; 3) FRPR-1 as well as FLP-1modulates the production and secretion of the predominant insulin-like peptide DAF-28, which is produced in ASI neurons; and 4) the suppression of larval diapause by frpr-1 loss-of-function is completely suppressed by a daf-28 defect.
View Article and Find Full Text PDFTissue Cell
January 2025
Department of Endocrinology, Fuyang Cancer Hospital, Fuyang, Anhui Province 236000, PR China. Electronic address:
Background: Diabetes mellitus (DM), a chronic metabolic disease, is characterized by long-term hyperglycemia resulting from the defect of insulin production and insulin resistance. The damage and dysfunction of pancreatic β-cells is a main link in DM development.
Methods: In this work, pancreatic β-cell line INS-1E cells were exposed to 30 mM glucose for 48 h to construct an in vitro DM model.
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