TY - JOUR
T1 - Glucagon does not affect catecholamine release in primary cultures of bovine adrenal chromaffin cells
AU - Sharabi, Yehonatan
AU - Zimlichman, R.
AU - Alesci, S.
AU - Huynh, T.
AU - Mansouri, R.
AU - Chun, J.
AU - Perera, S.
AU - Pacak, K.
AU - Goldstein, D. S.
PY - 2005/4
Y1 - 2005/4
N2 - Objective: Human pheochromocytoma tumor cells express glucagon receptors, and bolus i.v. glucagon injection rapidly increases plasma epinephrine levels, suggesting that glucagon can directly stimulate adrenomedullary secretion. In this study, we tested whether the catecholamine secretory response to glucagon was present in bovine chromaffin cells or exclusive to the tumor cells. Design and Methods: Adrenomedullary cells were cultured in 24-well plates (10 6 cells per well). After 48-72 hours, wells were incubated for 1-20 minutes with (1) incubation medium (control), (2) catecholamine secretagogues (nicotine or potassium ion), or (3) glucagon (10-8 to 10-5 M). After incubation, catecholamine contents in medium and cells were assayed by high-pressure liquid chromatography with electrochemical detection. Fractional release rates of epinephrine, norepinephrine, and dopamine were calculated and compared to controls. Reverse-transcriptase PCR was performed to compare expression of mRNA of the glucagon receptor in chromaffin cells and pheochromocytoma cells. Results: Nicotine and potassium evoked time-dependent release of epinephrine, norepinephrine, and dopamine. Glucagon did not affect catecholamine secretion at any concentration. Reverse-transcriptase PCR failed to detect mRNA for glucagon receptor in bovine adrenomedullary cells, but did detect it in human pheochromocytoma cells. Conclusions: In contrast to pheochromocytoma tumor cells, bovine adrenomedullary chromaffin cells do not express the glucagon receptor, and therefore do not secrete catecholamines in response to glucagon.
AB - Objective: Human pheochromocytoma tumor cells express glucagon receptors, and bolus i.v. glucagon injection rapidly increases plasma epinephrine levels, suggesting that glucagon can directly stimulate adrenomedullary secretion. In this study, we tested whether the catecholamine secretory response to glucagon was present in bovine chromaffin cells or exclusive to the tumor cells. Design and Methods: Adrenomedullary cells were cultured in 24-well plates (10 6 cells per well). After 48-72 hours, wells were incubated for 1-20 minutes with (1) incubation medium (control), (2) catecholamine secretagogues (nicotine or potassium ion), or (3) glucagon (10-8 to 10-5 M). After incubation, catecholamine contents in medium and cells were assayed by high-pressure liquid chromatography with electrochemical detection. Fractional release rates of epinephrine, norepinephrine, and dopamine were calculated and compared to controls. Reverse-transcriptase PCR was performed to compare expression of mRNA of the glucagon receptor in chromaffin cells and pheochromocytoma cells. Results: Nicotine and potassium evoked time-dependent release of epinephrine, norepinephrine, and dopamine. Glucagon did not affect catecholamine secretion at any concentration. Reverse-transcriptase PCR failed to detect mRNA for glucagon receptor in bovine adrenomedullary cells, but did detect it in human pheochromocytoma cells. Conclusions: In contrast to pheochromocytoma tumor cells, bovine adrenomedullary chromaffin cells do not express the glucagon receptor, and therefore do not secrete catecholamines in response to glucagon.
KW - Adrenal medulla
KW - Catecholamines
KW - Chromaffin cell
KW - Glucagon
KW - Pheochromocytoma
UR - http://www.scopus.com/inward/record.url?scp=19944406796&partnerID=8YFLogxK
U2 - 10.1055/s-2005-861415
DO - 10.1055/s-2005-861415
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C2 - 15952078
AN - SCOPUS:19944406796
SN - 0018-5043
VL - 37
SP - 205
EP - 208
JO - Hormone and Metabolic Research
JF - Hormone and Metabolic Research
IS - 4
ER -