Hepatische Elimination und First-Pass-Effekt von Glucagon-Like Peptide-1 (GLP-1)

2006 ◽  
Vol 34 (02) ◽  
pp. 132-137
Author(s):  
A. Greischel ◽  
W. Roth ◽  
J.P. Sandel

Zusammenfassung Gegenstand und Ziel: Ein neuer, innovativer Ansatz in der humanmedizinischen Behandlung des nichtinsulinabhängigen Diabetes mellitus (Typ 2) zielt auf die Hemmung der Dipeptidyl-Peptidase IV (DPP-IV) ab, um die Plasmakonzentration an Glucagon-Like Peptide-1 (GLP-1) zu erhöhen, wodurch wiederum die Insulininkretion in Abhängigkeit von erhöhten Blutzuckerspiegeln gesteigert wird. Material und Methoden: In der vorliegenden Studie wurde der Anteil der hepatischen Elimination des GLP-1 an der Gesamtkörper-Elimination mit und ohne DPP-IV-Hemmung mithilfe des rezirkulierenden Modells der isolierten perfundierten Rat- tenleber (IPRL) quantifiziert. Ergebnisse: Die Leberelimination hat bei der Ratte einen Anteil von 57% an der totalen Clearance des GLP-1. Der niedrige hepatische Extraktionsquotient von 30 ± 11% erlaubt sieben von zehn vom Darm abgegebenen GLP-1-Molekülen den Eintritt in den systemischen Kreislauf (70% Bioverfügbarkeit). Die Halbwertszeit der GLP-1-Amid-Isoform (7–36 amid) in der IPRL beträgt 5,0 ± 1,3 Minuten und unterscheidet sich statistisch nicht signifikant (p = 0,114) von der Halbwertszeit der Glycin-Isoform (7–37) mit 6,1 ± 1,6 Minuten. Schlussfolgerung und klinische Relevanz: DPP-IV-Inhibitoren verlängern erfolgreich die Halbwertszeit und damit die Wirkdauer von GLP-1, was den Einsatz von Insulin bei Katzen mit Diabetes mellitus verzichtbar machen könnte.

2003 ◽  
Vol 31 (3) ◽  
pp. 529-540 ◽  
Author(s):  
BD Green ◽  
VA Gault ◽  
MH Mooney ◽  
N Irwin ◽  
CJ Bailey ◽  
...  

Although the incretin hormone glucagon-like peptide-1 (GLP-1) is a potent stimulator of insulin release, its rapid degradation in vivo by the enzyme dipeptidyl peptidase IV (DPP IV) greatly limits its potential for treatment of type 2 diabetes. Here, we report two novel Ala(8)-substituted analogues of GLP-1, (Abu(8))GLP-1 and (Val(8))GLP-1 which were completely resistant to inactivation by DPP IV or human plasma. (Abu(8))GLP-1 and (Val(8))GLP-1 exhibited moderate affinities (IC(50): 4.76 and 81.1 nM, respectively) for the human GLP-1 receptor compared with native GLP-1 (IC(50): 0.37 nM). (Abu(8))GLP-1 and (Val(8))GLP-1 dose-dependently stimulated cAMP in insulin-secreting BRIN BD11 cells with reduced potency compared with native GLP-1 (1.5- and 3.5-fold, respectively). Consistent with other mechanisms of action, the analogues showed similar, or in the case of (Val(8))GLP-1 slightly impaired insulin releasing activity in BRIN BD11 cells. Using adult obese (ob/ob) mice, (Abu(8))GLP-1 had similar glucose-lowering potency to native GLP-1 whereas the action of (Val(8))GLP-1 was enhanced by 37%. The in vivo insulin-releasing activities were similar. These data indicate that substitution of Ala(8) in GLP-1 with Abu or Val confers resistance to DPP IV inactivation and that (Val(8))GLP-1 is a particularly potent N-terminally modified GLP-1 analogue of possible use in type 2 diabetes.


2021 ◽  
Vol 11 (5) ◽  

Dipeptidyl peptidase IV is a key regulator of insulin- stimulating hormones, glucagon-like peptide and glucose dependent insulinotrophic polypeptide. Thus it is a promising target for treatment of type 2 Diabetes mellitus. Inhibition of plasma Dipeptidyl peptidase IV enzyme lead to enhanced endogenous glucagon like peptide-1, GIP activity which ultimately results in the potentiating of insulin secretion by pancreatic cell and subsequent lowering blood glucose level, HbA [1c], glucose secretion, liver glucose production. One of the principal goals of diabetes management is to attain haemoglobin HbA [1c] treatment goals and prevent the onset or decrease the rate of occurrence of Microvascular conditions.2, 6 numerous treatment options are available for management of Type 2 Diabetes mellitus, various class of DPP IV inhibitor being explored such as Sitagliptin and Vildagliptin successfully launched. Several other novel DPP IV inhibitors are in pipeline, Unless there are clear contraindications, metformin monotherapy is prescribed, and if HbA [1c] targets are not attained after 3 months, 1 of several classes of agents could be added, such as sulfonylurea’s, Thiazolidinediones, dipeptidyl peptidase-4 inhibitors, - glucagon like peptide-1 receptor agonists, or basal insulin.2,6 Despite the broad range of therapeutic options, the attainment of HbA [1c] goals among patients with diabetes remains challenging, with just slightly more than half (52%) of diabetes patients attaining the common HbA [1c] goal of < 7.0%. The present review summarizes latest preclinical and clinical trial data of different DPP IV inhibitors with a special emphasis on their DPP8/9 fold selectivity and therapeutic advantages over GLP-1 based approach. Keywords: Diabetes 2, Dipeptidyl Peptidase-4, glucose-dependent insulinot


2004 ◽  
Vol 180 (3) ◽  
pp. 379-388 ◽  
Author(s):  
BD Green ◽  
MH Mooney ◽  
VA Gault ◽  
N Irwin ◽  
CJ Bailey ◽  
...  

Glucagon-like peptide-1(7-36)amide (GLP-1) possesses several unique and beneficial effects for the potential treatment of type 2 diabetes. However, the rapid inactivation of GLP-1 by dipeptidyl peptidase IV (DPP IV) results in a short half-life in vivo (less than 2 min) hindering therapeutic development. In the present study, a novel His(7)-modified analogue of GLP-1, N-pyroglutamyl-GLP-1, as well as N-acetyl-GLP-1 were synthesised and tested for DPP IV stability and biological activity. Incubation of GLP-1 with either DPP IV or human plasma resulted in rapid degradation of native GLP-1 to GLP-1(9-36)amide, while N-acetyl-GLP-1 and N-pyroglutamyl-GLP-1 were completely resistant to degradation. N-acetyl-GLP-1 and N-pyroglutamyl-GLP-1 bound to the GLP-1 receptor but had reduced affinities (IC(50) values 32.9 and 6.7 nM, respectively) compared with native GLP-1 (IC(50) 0.37 nM). Similarly, both analogues stimulated cAMP production with EC(50) values of 16.3 and 27 nM respectively compared with GLP-1 (EC(50) 4.7 nM). However, N-acetyl-GLP-1 and N-pyroglutamyl-GLP-1 exhibited potent insulinotropic activity in vitro at 5.6 mM glucose (P<0.05 to P<0.001) similar to native GLP-1. Both analogues (25 nM/kg body weight) lowered plasma glucose and increased plasma insulin levels when administered in conjunction with glucose (18 nM/kg body weight) to adult obese diabetic (ob/ob) mice. N-pyroglutamyl-GLP-1 was substantially better at lowering plasma glucose compared with the native peptide, while N-acetyl-GLP-1 was significantly more potent at stimulating insulin secretion. These studies indicate that N-terminal modification of GLP-1 results in DPP IV-resistant and biologically potent forms of GLP-1. The particularly powerful antihyperglycaemic action of N-pyroglutamyl-GLP-1 shows potential for the treatment of type 2 diabetes.


2002 ◽  
Vol 172 (2) ◽  
pp. 355-362 ◽  
Author(s):  
CF Deacon ◽  
S Wamberg ◽  
P Bie ◽  
TE Hughes ◽  
JJ Holst

The incretin hormones glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) are degraded by dipeptidyl peptidase IV (DPP IV), thereby losing insulinotropic activity. DPP IV inhibition reduces exogenous GLP-1 degradation, but the extent of endogenous incretin protection has not been fully assessed, largely because suitable assays which distinguish between intact and degraded peptides have been unavailable. Using newly developed assays for intact GLP-1 and GIP, the effect of DPP IV inhibition on incretin hormone metabolism was examined. Conscious dogs were given NVP-DPP728, a specific DPP IV inhibitor, at a dose that inhibited over 90% of plasma DPP IV for the first 90 min following treatment. Total and intact incretin concentrations increased (P<0.0001) following a mixed meal, but on control days (vehicle infusion), intact peptide concentrations were lower (P<0.01) than total peptide concentrations (22.6 +/- 1.2% intact GIP; 10.1 +/- 0.4% intact GLP-1). Following inhibitor treatment, the proportion of intact peptide increased (92.5 +/- 4.3% intact GIP, P<0.0001; 99.0 +/- 22.6% intact GLP-1, P<0.02). Active (intact) incretins increased after NVP-DPP728 (from 4797 +/- 364 to 10 649 +/- 106 pM x min for GIP, P<0.03; from 646 +/- 134 to 2822 +/- 528 pM x m in for GLP-1, P<0.05). In contrast, total incretins fell (from 21 632 +/- 654 to 12 084 +/- 1723 pM x min for GIP, P<0.002; from 5145 +/- 677 to 3060 +/- 601 pM x min for GLP-1, P<0.05). Plasma glucose, insulin and glucagon concentrations were unaltered by the inhibitor. We have concluded that DPP IV inhibition with NVP-DPP728 prevents N-terminal degradation of endogenous incretins in vivo, resulting in increased plasma concentrations of intact, biologically active GIP and GLP-1. Total incretin secretion was reduced by DPP IV inhibition, suggesting the possibility of a feedback mechanism.


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