TY - JOUR
T1 - N-terminal glycation of cholecystokinin-8 abolishes its insulinotropic action on clonal pancreatic B-cells
AU - Abdel-Wahab, Yasser H.A.
AU - O'Harte, Finbarr P.M.
AU - Mooney, Mark H.
AU - Conlon, J. Michael
AU - Flatt, Peter R.
N1 - Funding Information:
These studies were supported by Northern Ireland Developmental Research Funding (NIdevR).
PY - 1999/10/13
Y1 - 1999/10/13
N2 - Monoglycated cholecystokinin octapeptide (Asp1-glucitol CCK-8) was prepared under hyperglycaemic reducing conditions and purified by reverse phase-high performance liquid chromatography. Electrospray ionisation mass spectrometry and automated Edman degradation demonstrated that CCK-8 was glycated specifically at the amino-terminal Asp1 residue. Effects of Asp1- glucitol CCK-8 and CCK-8 on insulin secretion were examined using glucose- responsive clonal BRIN-BD11 cells. In acute (20 min) incubations, 10-10 mol/l CCK-8 enhanced insulin release by 1.2-1.5-fold at 5.6-11.1 mmol/l glucose. The stimulatory effect induced by 10-10 mol/l CCK-8 was abolished following glycation. At 5.6 mmol/l glucose, CCK-8 at concentrations ranging from 10-11 to 10-7 mol/l induced a significant 1.6-1.9-fold increase in insulin secretion. Insulin output in the presence of Asp1-glucitol CCK-8 over the concentration range 10-11-10-7 mol/l was decreased by 21-35% compared with CCK-8, and its insulinotropic action was effectively abolished. Asp1-glucitol CCK-8 at 10-8 mol/l also completely blocked the stimulatory effects of 10-11-10-8 mol/l CCK-8. These data indicate that structural modification by glycation at the amino-terminal Asp1 residue effectively abolishes and/or antagonises the insulinotropic activity of CCK-8.
AB - Monoglycated cholecystokinin octapeptide (Asp1-glucitol CCK-8) was prepared under hyperglycaemic reducing conditions and purified by reverse phase-high performance liquid chromatography. Electrospray ionisation mass spectrometry and automated Edman degradation demonstrated that CCK-8 was glycated specifically at the amino-terminal Asp1 residue. Effects of Asp1- glucitol CCK-8 and CCK-8 on insulin secretion were examined using glucose- responsive clonal BRIN-BD11 cells. In acute (20 min) incubations, 10-10 mol/l CCK-8 enhanced insulin release by 1.2-1.5-fold at 5.6-11.1 mmol/l glucose. The stimulatory effect induced by 10-10 mol/l CCK-8 was abolished following glycation. At 5.6 mmol/l glucose, CCK-8 at concentrations ranging from 10-11 to 10-7 mol/l induced a significant 1.6-1.9-fold increase in insulin secretion. Insulin output in the presence of Asp1-glucitol CCK-8 over the concentration range 10-11-10-7 mol/l was decreased by 21-35% compared with CCK-8, and its insulinotropic action was effectively abolished. Asp1-glucitol CCK-8 at 10-8 mol/l also completely blocked the stimulatory effects of 10-11-10-8 mol/l CCK-8. These data indicate that structural modification by glycation at the amino-terminal Asp1 residue effectively abolishes and/or antagonises the insulinotropic activity of CCK-8.
KW - BRIN-BD11 cell
KW - Cholecystokinin-8
KW - Glycation
KW - Insulin secretion
UR - http://www.scopus.com/inward/record.url?scp=0032881940&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0032881940&partnerID=8YFLogxK
U2 - 10.1016/S0167-4889(99)00108-1
DO - 10.1016/S0167-4889(99)00108-1
M3 - Article
C2 - 10525160
AN - SCOPUS:0032881940
SN - 0167-4889
VL - 1452
SP - 60
EP - 67
JO - Biochimica et Biophysica Acta - Molecular Cell Research
JF - Biochimica et Biophysica Acta - Molecular Cell Research
IS - 1
ER -