Colocalization of insulin and glucagon in insulinoma cells and developing pancreatic endocrine cells.
A significant portion of human and rat insulinomas coexpress multiple hormones. This character termed as multihormonality is also observed in some early pancreatic endocrine cells which coexpress insulin and glucagon, suggesting an incomplete differentiation status of both cells. Here we demonstrate that insulinoma cells INS-1 and INS-1-derived single cell clone INS-1-15 coexpressed insulin and glucagon in a portion of cells. These two hormones highly colocalized in the intracellular vesicles within a cell. Due to the existence of both PC1/3 and PC2 in INS-1-derived cells, proglucagon could be processed into glucagon, GLP-1 and GLP-2. These glucagon-family peptides and insulin were secreted simultaneously corresponding to the elevating glucose concentrations. The coexpression and partial colocalization of insulin and glucagon was also observed in rat fetal pancreatic endocrine cells, but the colocalization rate was generally lower and more diverse, suggesting that in the developing pancreatic endocrine cells, insulin and glucagon may be stored in nonidentical pools of secreting vesicles and might be secreted discordantly upon stimulus.
Institute of Clinical Medical Sciences, China-Japan Friendship Hospital, Beijing 100029, PR China.
Zai
Z
Wang
Institute of Clinical Medical Sciences, China-Japan Friendship Hospital, Beijing 100029, PR China.
Jia
J
You
Institute of Clinical Medical Sciences, China-Japan Friendship Hospital, Beijing 100029, PR China.
Shiqing
S
Xu
Department of General Surgery, China-Japan Friendship Hospital, Beijing 100029, PR China.
Zhan
Z
Hua
Institute of Clinical Medical Sciences, China-Japan Friendship Hospital, Beijing 100029, PR China.
Wenjian
W
Zhang
Institute of Clinical Medical Sciences, China-Japan Friendship Hospital, Beijing 100029, PR China.
Tingting
T
Deng
Wangjing Hospital, China Academy of Chinese Medical Sciences, Beijing 100102, PR China.
Ni
N
Fang
Institute of Clinical Medical Sciences, China-Japan Friendship Hospital, Beijing 100029, PR China.
Qing
Q
Fang
Institute of Clinical Medical Sciences, China-Japan Friendship Hospital, Beijing 100029, PR China.
Honglin
H
Liu
Institute of Clinical Medical Sciences, China-Japan Friendship Hospital, Beijing 100029, PR China.
Liang
L
Peng
Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, PR China.
Peigang
P
Wang
Institute of Clinical Medical Sciences, China-Japan Friendship Hospital, Beijing 100029, PR China. Electronic address: Lou.j@mail.com.
Jinning
J
Lou
D000818:Animals; D002460:Cell Line; D055098:Endocrine Cells / Q000378:metabolism* / Q000473:pathology; D005934:Glucagon; D007328:Insulin / Q000378:metabolism*; D007340:Insulinoma / Q000378:metabolism* / Q000473:pathology; D051379:Mice; D010179:Pancreas / Q000378:metabolism* / Q000473:pathology; D010190:Pancreatic Neoplasms / Q000378:metabolism* / Q000473:pathology; D051381:Rats; D013347:Subcellular Fractions / Q000378:metabolism*; D014018:Tissue Distribution
D007328:Insulin; D005934:Glucagon
Colocalization; Cosecretion; Glucagon; INS-1; Insulin