(Journal Article): Degradation of glucagon-like peptide-1 by human plasma in vitro yields an N-terminally truncated peptide that is a major endogenous metabolite in vivo.
 
Deacon CF, Johnsen AH, Holst JJ (Department of Medical Physiology, Panum Institute, University of Copenhagen, Denmark.)
 
IN: J Clin Endocrinol Metab 1995; 80(3):952-957
Impact Factor(s) of J Clin Endocrinol Metab: 5.778 (2004), 5.873 (2003), 5.16 (2001)

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ABSTRACT: The metabolism of glucagon-like peptide-1 (GLP-1) has not been studied in detail, but it is known to be rapidly cleared from the circulation. Measurement by RIA is hampered by the fact that most antisera are side-viewing or C-terminally directed, and recognize both intact GLP-1 and biologically inactive N-terminally truncated fragments. Using high pressure liquid chromatography in combination with RIAs, methodology allowing specific determination of both intact GLP-1 and its metabolites was developed. Human plasma was shown to degrade GLP-1-(7-36)amide, forming an N-terminally truncated peptide with a t1/2 of 20.4 +/- 1.4 min at 37 C (n = 6). This was unaffected by EDTA or aprotinin. Inhibitors of dipeptidyl peptidase-IV or low temperature (4 C) completely prevented formation of the metabolite, which was confirmed to be GLP-1-(9-36)amide by mass spectrometry and sequence analysis. High pressure liquid chromatography revealed the concentration of GLP-1-(9-36)amide to be 53.5 +/- 13.7% of the concentration of endogenous intact GLP-1 in the fasted state, which increased to 130.8 +/- 10.0% (P < 0.01; n = 6) 1 h postprandially. Metabolism at the C-terminus was not observed. This study suggests that dipeptidyl peptidase-IV is the primary mechanism for GLP-1 degradation in human plasma in vitro and may have a role in inactivating the peptide in vivo.

TYPE OF PUBLICATION: Original article

REFERENCES:

1. Holst JJ. Gut glucagon, enteroglucagon, gut glucagonJike immunoreactivity, glicentin-current status. Gastroenterology 1983. 84:1602-1613. [DOD]
2. 0rskov e. Glucagon-like peptide-1, a new hormone of the entero-insular axis. Diabetologia 1992. 35:701-711. [DOD]
3. 0rskov C, Holst JJ, Nielsen OV. Effect of truncated glucagon-like nentide-l rnro!ducaQ:on-(7R-107)amidel on endocrine SPCTption from pig pancreas, antrum, and nonantral stornach. Endocrinology 1988. 123:2009-2013. [DOD]
4. Creutzfeldt W, Ebert R. New developments in the incretin concept. Diabetologia 1985. 28:565-573. [DOD]
5. Kreymann B, Williams G, Ghatei MA, Bloom SR. Glucagon-like peptide 1 7-36: a physiological incretin in man. Lancet 1987. 2:1300-1304.
6. Holst JJ, 0rskov C. 1994 Glucagon and other proglucagon-derived peptides. In: Walsh JH, Dochrayq, eds. Gut peptides: biochemistry and physiology. New York: Raven Press; 305-340. [DOD]
7. Ruiz-Grande C, Pintado J, Alarcon C, Castilla C, Valverde I, Lopez-Novoa JM. Renal catabolism of human glucagon-like peptides 1 and 2. Can J Physiol Pharmacol 1990. 68:1568-1573. [DOD]
8. Ruiz-Grande C, Alarcon C, Alcantara A, et al. Renal catabolism of truncated glucagon-like peptide 1. Horm Metab Res 1993. 25:612-616.
9. 0rskov C, Andreasen J, Holst JJ. All products of proglucagon are elevated in plasma trom UTemic patients. J Clin Endocrinol Metab 1992. 74:379-384. [DOD]
10. Mentlein R, Gallwitz B, Schmidt WE. Dipeptidyl-peptidase IV hydrolyses gastric inhibitory polypeptide, glucagon-like peptide-l(7-36)amide, and peptide histidine methionine and is responsible for their degradation in human serum. Eur J Biochem 1993. 214:829-835. [DOD]
11. Buckley DI, Lundquist P. Analysis of the degradation of insulinotropin [GLP-1 (7-37)1 in human plasma and production of degradation resistant analogs. Regul Pept 1992. 40:117.
12. 0rskov C, Holst JJ, Seier Poulsen S, Kirkegaard P. Pancreatic and intestinal processing of proglucagon in man. Diabetologia 1987. 30:874-881. [DOD]
13. 0rskov C, Jeppesen J, Madsbad S, Holst JJ. Proglucagon products in plasma of non-insulin dependent diabetics and nondiabetic controls in the fasting state and following oral glucose and intravenous arginine. J Clin Invest 1991. 87:415-423. [DOD]
14. Holst JJ, Bersani M, Johnsen AH, Kofod H, Hartmann B, 0rskove. Proglucagon processing in porcine and human pancreas. J Biol Chem 1994. 269:18827-18833. [DOD]
15. Hvidberg A, Nielsen MT, Hilsted J, 0rslov C, Holst JJ. Effect of glucagon-like peptide-1 (proglucagon 78-107amide) on hepatic glucose production in healthy man. Metabolism 1994. 43:104-108. [DOD]
16. Bella AM, Erikson RH, Kim YS. Rat intestinal brush border membrane dipeptidyl aminopeptidase IV: kinetic properties and substrate specificity of the purified enzyme. Arch Biochem Biophys 1982. 218:156-162. [DOD]
17. RahfeldJ, Schierhorn M, Hartrodt B, Neubert K, Heins J. Are diprotin A (Ile-Pro-He) and diprotin B (Val-Pro-Leu) inhibitors or substrates for dipeptidyl peptidase IV? Biochim Biophys Acta 1991. 1076:314-316. [DOD]
18. Struckhoff G. Beitrag zur Biologie der Dipeptidylpeptidasen II und IV. PhD Thesis 1987. Kiel: Christian-Albrechts-Universität.
19. Kenny AJ, Booth AG, George SC, et al. Dipeptidyl peptidase IV, a kidney brush border serine peptidase. Biochem J 1976. 157:169-182. [DOD]
20. Lojda Z. Studies on dipeptidyl(amino)peptidase IV (glycylproline-naphthylamidase) in blood vessels. Histochemistry 1979. 59:153-166. [DOD]
21. Elovson J. Biogenesis of plasma membrane glycoproteins. Purification and properties of two rat liver membrane glycoproteins. J Biol Chem 1980. 255:5807-5815. [DOD]
22. Gefel D, Hendrick GK, Mojsov S, Habener J, Weir GE. Glucagon-like peptide I analogues: effects on insulin secretion and adenosine 3',5'-monophosphate formation. Endocrinology 1990. 126:2164-2168. [DOD]
23. Gallwitz B, Schmidt WE, Conlon JM, Creutzfeldt W. Glucagon-like peptide 1(7-36)amide: characterization of the domain responsible for binding to its receptor on rat insulinoma RINm5F cells. J Mol Endocrinol 1990. 5:33-39. [DOD]
24. Adelhorst K, Hedegaard BB, Knudsen LB, Kirk 0. Structureactivity studies of glucagon-like peptide-l. J Biol Chem 1994. 269:6275-6278. [DOD]
25. Grandt D, Sieburg B, Sievert J, et al. Is GLP-l (9-36)amide an endogenous antagonist at GLP-l receptors? Digestion 1994. 55:302. [DOD]
26. Schjoldager BTG, Mortensen P-E, Christiansen J, 0rskov C, Holst JJ. (;J .P-11S"111rap'on-likp_n.entirlp..n ~nci trllncments of human proglucagon, inhibit gastric aeid secretion in man. Dig Dis Sei 1989. 35:703-708.
27. Wettergren A, Schjoldager B, Mortensen PE, Myhre J, Chrisnansen J, Holst JJ. Truncated GLP-l (proglucagon 78-107 amide) inhibits gastrie and pancreatie functions in man. Dig Dis Sei 1993. 38:665-673. [DOD]
28. 0rskov C, Wettergren A, Holst JJ. Biologieal effects and metabolic rates of glucagon-Jike peptide-l 7-36 amide and glucagon-like peptide-l 7-37 in healthy subjects are indistinguishable. Diabetes 1993. 42:658-661. [DOD]
29. Hendrick GK, Gjinovci A, Baxter LA, et al. Glucagon-like peptide-l (7-37) suppresses hyperglyeaemia in rats. Metabolism 1993. 42:1-6. [DOD]
30. Emmanouel DS, Jaspan JB, Rubenstein AH, Huen AH-J, Fink E, Katz AI. Glucagon metabolism in the rat. Contributions of the kidney to the metabolie clearance of the hormone. J Gin Invest 1978. 62:6-13. [DOD]
31. Holst JJ. Degradation of glucagons. In: Henriksen JH, ed. Degradation of bioaetive substances. .Physiology and pathophysiology. Boca Raton: CRC Press 1991. 167-180.