TY - JOUR
T1 - Involvement of cellular calcium in exocrine pancreatic insufficiency during streptozotocin-induced diabetes mellitus
AU - Singh, J.
AU - Yago, M. D.
AU - Adeghate, E.
N1 - Funding Information:
The work was supported by the Wellcome Trust, UCLAN and UAE University. We are grateful to Lisa Whittaker for typing the manuscript.
PY - 2001/7
Y1 - 2001/7
N2 - This study investigates the effects of the islet hormones insulin (Ins), glucagon (Glu), and somatostatin (Som) with nerve stimulation (EFS) acetylcholine (ACh) and cholecytokinin-octapeptide (CCK-8) on amylase secretion and intracellular free calcium concentration [Ca2+]i in the pancreas of age-matched control and diabetic rats. Either Ins, Glu or Som elicited small increases in amylase secretion from the pancreas of age-matched control animals compared to a much larger increase in amylase secretion with either EFS, ACh or CCK-8. Combining the islet hormones with either EFS, ACh or CCK-8 resulted in marked potentiation of amylase output. In the diabetic pancreas, the islet hormones had no effect on amylase secretion compared to diabetic control. Moreover, either EFS, ACh or CCK-8 evoked a much smaller increase in amylase output compared to age-matched control. In addition, the islet hormones failed to potentiate the secretory effects of either EFS, ACh or CCK8. In fura-2 loaded acinar cells from age-matched control pancreas either Ins or Glu elicited a small increase in [Ca2+]i whereas Som had no effect. Both ACh and CCK-8 evoked large increases in [Ca2+]i compared to control. Combining either Ins, Glu or Som with either ACh or CCK-8 resulted in a marked elevation in [Ca2+]i compared to the responses obtained with either the islet hormones, ACh or CCK-8 alone. In diabetic fura-2 loaded pancreatic acinar cells, the islet hormones had no effect on [Ca2+]i compared to control and moreover, the responses were much smaller than those obtained in acinar cells from age-matched control. Both ACh and CCK-8 induced large increases in [Ca2+]i in diabetic acinar cells. However, combining the islet hormones with either ACh or CCK-8 failed to enhance [Ca2+]i compared to the reponses obtained in acinar cells from age-matched control. The results suggests that [Ca2+]i homeostasis is deranged during diabetes mellitus and this in turn is probably associated with reduced pancreatic amylase secretion.
AB - This study investigates the effects of the islet hormones insulin (Ins), glucagon (Glu), and somatostatin (Som) with nerve stimulation (EFS) acetylcholine (ACh) and cholecytokinin-octapeptide (CCK-8) on amylase secretion and intracellular free calcium concentration [Ca2+]i in the pancreas of age-matched control and diabetic rats. Either Ins, Glu or Som elicited small increases in amylase secretion from the pancreas of age-matched control animals compared to a much larger increase in amylase secretion with either EFS, ACh or CCK-8. Combining the islet hormones with either EFS, ACh or CCK-8 resulted in marked potentiation of amylase output. In the diabetic pancreas, the islet hormones had no effect on amylase secretion compared to diabetic control. Moreover, either EFS, ACh or CCK-8 evoked a much smaller increase in amylase output compared to age-matched control. In addition, the islet hormones failed to potentiate the secretory effects of either EFS, ACh or CCK8. In fura-2 loaded acinar cells from age-matched control pancreas either Ins or Glu elicited a small increase in [Ca2+]i whereas Som had no effect. Both ACh and CCK-8 evoked large increases in [Ca2+]i compared to control. Combining either Ins, Glu or Som with either ACh or CCK-8 resulted in a marked elevation in [Ca2+]i compared to the responses obtained with either the islet hormones, ACh or CCK-8 alone. In diabetic fura-2 loaded pancreatic acinar cells, the islet hormones had no effect on [Ca2+]i compared to control and moreover, the responses were much smaller than those obtained in acinar cells from age-matched control. Both ACh and CCK-8 induced large increases in [Ca2+]i in diabetic acinar cells. However, combining the islet hormones with either ACh or CCK-8 failed to enhance [Ca2+]i compared to the reponses obtained in acinar cells from age-matched control. The results suggests that [Ca2+]i homeostasis is deranged during diabetes mellitus and this in turn is probably associated with reduced pancreatic amylase secretion.
KW - Acetylcholine
KW - Amylase
KW - Calcium
KW - Cholecystokinin-octapeptide
KW - Diabetes
KW - Electrical field stimulation
KW - Insufficiency
KW - Pancreas
KW - Rat
UR - http://www.scopus.com/inward/record.url?scp=0035412506&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0035412506&partnerID=8YFLogxK
U2 - 10.1076/apab.109.3.252.11585
DO - 10.1076/apab.109.3.252.11585
M3 - Article
C2 - 11880930
AN - SCOPUS:0035412506
SN - 1381-3455
VL - 109
SP - 252
EP - 259
JO - Archives of Physiology and Biochemistry
JF - Archives of Physiology and Biochemistry
IS - 3 SPEC ISS.
ER -