Effects of ghrelin and other neuropeptides (CART, MCH, orexin A and B, and GLP-1) on the release of insulin from isolated rat islets
M Colombo, S Gregersen, J Xiao, K Hermansen - Pancreas, 2003 - journals.lww.com
M Colombo, S Gregersen, J Xiao, K Hermansen
Pancreas, 2003•journals.lww.comMaterials and Methods Rat islets were incubated with 1 pmol/l–1 μmol/l of ghrelin, CART
fragments, MCH, orexin A or B, or GLP-1 (n= 16–32) in the presence of 16.7 mmol/l glucose.
Ghrelin (10 nmol/l) was added to islets at glucose concentrations of 3.3, 6.6, 16.7 and 25
mmol/l, respectively (n= 28–32). Also, INS-1E cells were incubated with ghrelin (1 nmol/l) in
the presence of glucose (3.3, 6.6, 16.7, and 25 mmol/l). In addition, we measured the mRNA
expression of the ghrelin receptor using RT-PCR. Results Ghrelin inhibited insulin secretion …
fragments, MCH, orexin A or B, or GLP-1 (n= 16–32) in the presence of 16.7 mmol/l glucose.
Ghrelin (10 nmol/l) was added to islets at glucose concentrations of 3.3, 6.6, 16.7 and 25
mmol/l, respectively (n= 28–32). Also, INS-1E cells were incubated with ghrelin (1 nmol/l) in
the presence of glucose (3.3, 6.6, 16.7, and 25 mmol/l). In addition, we measured the mRNA
expression of the ghrelin receptor using RT-PCR. Results Ghrelin inhibited insulin secretion …
Materials and Methods
Rat islets were incubated with 1 pmol/l–1 μmol/l of ghrelin, CART fragments, MCH, orexin A or B, or GLP-1 (n= 16–32) in the presence of 16.7 mmol/l glucose. Ghrelin (10 nmol/l) was added to islets at glucose concentrations of 3.3, 6.6, 16.7 and 25 mmol/l, respectively (n= 28–32). Also, INS-1E cells were incubated with ghrelin (1 nmol/l) in the presence of glucose (3.3, 6.6, 16.7, and 25 mmol/l). In addition, we measured the mRNA expression of the ghrelin receptor using RT-PCR.
Results
Ghrelin inhibited insulin secretion from islets and INS-1E cells in a dose-and glucose-dependent manner. Neither 10 pmol/l–1 μmol/l of CART fragments, MCH, orexin A, nor orexin B changed the insulin secretion at 16.7 mmol/l glucose, while GLP-1, as expected, stimulated the insulin release from rat islets. Interestingly, ghrelin receptors were expressed both in islets, INS-1E, MIN 6 and alpha cell Tca-9 lines.
Conclusions
Ghrelin inhibits the insulin secretion in vitro in a dose-and glucose-dependent manner. Beta cells contain ghrelin receptors. CART fragments did not affect the insulin secretion. Ghrelin may play a physiological role for the regulation of insulin secretion.
Lippincott Williams & Wilkins