At t = 30 min, animals consumed a liquid mixed meal, spiked with acetaminophen. All animals were studied twice (± Ex-9) in random fashion, and the experiments were separated by a 1-2-week washout period. Antagonism of the GLP-1R did not have an effect, as indicated by repeated-measures MANOVA analysis of the Δ AUC from t = 45-320 min of arterial plasma glucose, GLP-1, insulin, glucagon, and acetaminophen levels. Therefore, endogenous GLP-1 is not sufficient to alter postprandial glucose The insulinotropic effect of pulsatile compared with continuous intravenous Hospital, North Terrace, Adelaide, SA, 5000, Australia. Hospital, North Terrace, Adelaide, SA, 5000, Australia.Josef-Hospital, Ruhr-University Bochum, Bochum, Germany. AIMS/HYPOTHESIS: In healthy individuals, both insulin and glucagon-like peptide 1 (GLP-1) are secreted in a pulsatile fashion. Insulin has greater glucose-lowering properties when administered in pulses compared with a constant i.v. infusion. The primary aim of this randomised double-dummy cross-over study was to compare the insulinotropic response to pulsatile and continuous i.v. infusions of equivalent doses of GLP-1. METHODS: Twelve healthy participants aged 18-35 years were randomised to three different treatments on separate days: a continuous infusion day (GLP-1 at 0 pmol kg(-1) min(-1) [1 ml/min] and a 1 ml placebo bolus every 6 min); a pulsatile infusion day (placebo at 1 ml/min and a 3 pmol/kg GLP-1 bolus every 6 min); and a placebo day (placebo at 1 ml/min and a 1 ml placebo bolus every 6 min). Between 45 and 120 min, a hyperglycaemic clamp was used to maintain blood glucose at 9 mmol/l. Venous blood glucose and plasma insulin concentrations were measured every 5 min from 0 to 45 min and every 1 min from 45 to 120 min; plasma glucagon was measured every 15 min. The order of treatment was randomised by the Pharmacy Department and both study investigators and participants were blinded to the treatment arm. The dextrose requirement and glucagon data were analysed using repeated measures ANOVA and insulin data were analysed with a linear mixed effects maximum likelihood model.RESULTS: Continuous and pulsatile infusions of GLP-1 increased the dextrose requirement by ~threefold (p < 001) and increased insulin secretion by ~ninefold (p < 001). There was no difference in the effect of both treatments. Although hyperglycaemia reduced plasma glucagon concentrations, there was no difference between the treatment days.CONCLUSIONS/INTERPRETATION: In healthy individuals, pulsatile and continuous administration of i.v. GLP-1 appears to have comparable insulinotropic effects.TRIAL REGISTRATION: ACTRN12612001040853 FUNDING: This study was supported by the National Health and Medical Research Council (NHMRC) of Australia.A surface plasmon resonance assay for characterisation and epitope mapping of The incretin hormone glucagon-like peptide-1 (GLP-1) has been subject to substantial pharmaceutical research regarding the treatment of type 2 diabetes mellitus. However, quantification of GLP-1 levels remains complicated due to the low circulation concentration and concurrent existence of numerous metabolites, homologous peptides, and potentially introduced GLP-1 receptor agonists. Surface plasmon resonance (SPR) facilitates real-time monitoring allowing a more detailed characterisation of the interaction compared with conventional enzyme-linked immunosorbent assays (ELISA). In this paper, we describe the development of the first SPR assays for characterisation of anti-GLP-1 antibodies for ELISA purposes. Binding Endocrine function drugs were obtained on covalently immobilised anti-GLP-1 antibodies at 12°C, 25°C, and 40°C and fitted to a biomolecular (1:1) interaction model showing association rates of 11 × 103 to 44 × 103 M-1 s-1 and dissociation rates of 36 × 10-5 to 16 × 10-3 s-1 leading to affinities of 35 to 344 nM, depending on the temperature. Determination of thermodynamic properties revealed an enthalpy driven interaction (ΔH < ΔS < 0) with higher affinities at lower temperatures due to the formation and stabilisation of hydrogen bonds within the binding site primarily composed of polar amino acids (ΔCp < 0). Pair-wise epitope mapping was performed on captured anti-GLP-1 antibodies followed by subsequent interaction with GLP-1 (7-36) and other anti-GLP-1 antibodies. A global evaluation of every binding response led to an epitope map elucidating the potential of various anti-GLP-1 antibody pairs for sandwich ELISA and hence pinpointing the optimal antibody combinations. glipizide used for proved capable of providing vital information for ELISA development endorsing it as a useful Clinical efficacy and safety of once-weekly glucagon-like peptide-1 agonists in development for treatment of type 2 diabetes mellitus in adults.
Endocrine function drugs|glipizide used for
