TY - JOUR
T1 - Cultured Astrocytes and Neurons Synthesize and Secrete Carboxypeptidase E, a Neuropeptide‐Processing Enzyme
AU - Vilijn, Marie‐Hélène ‐H
AU - Das, Banasree
AU - Kessler, John A.
AU - Flicker, Lloyd D.
PY - 1989/11
Y1 - 1989/11
N2 - Abstract: Carboxypeptidase E (EC 3.4.17.10) is a carboxy‐peptidase B‐like enzyme associated with the biosynthesis of many peptide hormones and neurotransmitters. Media collected from cultured astrocytes contain a carboxypeptidase E‐like activity. Cultured astrocytes secrete ∼73% of their cellular level of carboxypeptidase E per hour, and secretion is not substantially influenced by 35 mM KCI. In contrast, neurons secrete only 29% of their cellular carboxypeptidase E per hour, but secretion increases to 86% on stimulation with 35 mM KCI. Secretion of carboxypeptidase E activity from both neuronal and astrocyte cultures is relatively selective; neither acid phosphatase or acetylglucosaminidase is secreted in appreciable amounts. Cultured neurons and astrocytes express a carboxypeptidase E mRNA of a similar size. The levels of this mRNA differ in astrocytes cultured from different brain regions, with high levels in striatal, cortical, hippocampal, and hypothalamic astrocytes and low levels in cerebellar astrocytes. The level of carboxypeptidase E mRNA in hypothalamic astrocyte cultures is four‐ to fivefold higher than the level in hypothalamic neuronal cultures. These results indicate that cultured astrocytes express carboxypeptidase E mRNA and enzymatic activity and thus contain one of the enzymes required in the biosynthesis of many peptide hormones and neurotransmitters.
AB - Abstract: Carboxypeptidase E (EC 3.4.17.10) is a carboxy‐peptidase B‐like enzyme associated with the biosynthesis of many peptide hormones and neurotransmitters. Media collected from cultured astrocytes contain a carboxypeptidase E‐like activity. Cultured astrocytes secrete ∼73% of their cellular level of carboxypeptidase E per hour, and secretion is not substantially influenced by 35 mM KCI. In contrast, neurons secrete only 29% of their cellular carboxypeptidase E per hour, but secretion increases to 86% on stimulation with 35 mM KCI. Secretion of carboxypeptidase E activity from both neuronal and astrocyte cultures is relatively selective; neither acid phosphatase or acetylglucosaminidase is secreted in appreciable amounts. Cultured neurons and astrocytes express a carboxypeptidase E mRNA of a similar size. The levels of this mRNA differ in astrocytes cultured from different brain regions, with high levels in striatal, cortical, hippocampal, and hypothalamic astrocytes and low levels in cerebellar astrocytes. The level of carboxypeptidase E mRNA in hypothalamic astrocyte cultures is four‐ to fivefold higher than the level in hypothalamic neuronal cultures. These results indicate that cultured astrocytes express carboxypeptidase E mRNA and enzymatic activity and thus contain one of the enzymes required in the biosynthesis of many peptide hormones and neurotransmitters.
KW - Carboxypeptidase B‐like enzyme
KW - Carboxypeptidase E
KW - Carboxypeptidase H
KW - Enkephalin convertase
KW - Neuropeptide processing
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U2 - 10.1111/j.1471-4159.1989.tb08542.x
DO - 10.1111/j.1471-4159.1989.tb08542.x
M3 - Article
C2 - 2795014
AN - SCOPUS:0024431391
SN - 0022-3042
VL - 53
SP - 1487
EP - 1493
JO - Journal of neurochemistry
JF - Journal of neurochemistry
IS - 5
ER -