Metallothionein is a component of exocrine pancreas secretion: Implications for zinc homeostasis

被引:68
作者
DeLisle, RC
Sarras, MP
Hidalgo, J
Andrews, GK
机构
[1] UNIV KANSAS, MED CTR, DEPT BIOCHEM & MOL BIOL, KANSAS CITY, KS 66160 USA
[2] UNIV AUTONOMA BARCELONA, FAC CIENCIAS, UNIDAD FISIOL ANIM, DEPT BIOL CELULAR & FISIOL, BARCELONA 08193, SPAIN
来源
AMERICAN JOURNAL OF PHYSIOLOGY-CELL PHYSIOLOGY | 1996年 / 271卷 / 04期
关键词
transgenic mice; ultrastructural localization; pilocarpine; pancreatic juice;
D O I
10.1152/ajpcell.1996.271.4.C1103
中图分类号
Q2 [细胞生物学];
学科分类号
071009 ; 090102 ;
摘要
Using transgenic mice that overexpress metallothionein-I (MT-I) and zinc-induced normal and transgenic animals, we have explored the localization of MT in the pancreas. Light-level immunocytochemistry demonstrated MT in acinar cells but not islet cells. Immunolabeling also revealed the presence of MT in pancreatic ducts, suggesting that it is released from acinar cells. Ultrastructural immunolocalization showed that MT was cytoplasmic, and no MIT immunoreactivity was detected in lumens of the vesicular secretory pathway. Secreted pancreatic juice was collected from pilocarpine-stimulated mice and assayed for MT by a Cd-109-labeled hemoglobin-exchange assay and by radioimmunoassay. Both methods revealed high (>1,000 ng/ml) levels of MT in the stimulated secretion. The level of MT in pancreatic juice from transgenic mice was only slightly (2-fold) increased despite dramatic overexpression of MT-I in the pancreas (>20-fold). In contrast, zinc induction of MT significantly increased MT by 5- to 10-fold in the pancreatic juice, in normal and transgenic mice. These data indicate that MT is released from pancreatic acinar cells but not by the classical vesicular secretory pathway. In addition, MT levels in pancreatic juice are regulated by zinc, suggesting a physiological role of the pancreas in metal homeostasis.
引用
收藏
页码:C1103 / C1110
页数:8
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