ONTOGENY OF PREPROCHOLECYSTOKININ MRNA AND CHOLECYSTOKININ IN RAT BRAIN

对CCK编码基因的表达进行了研究 大鼠出生前后脑组织中前原CCK特异性cDNAs的表达 量化信使核糖核酸。此外，c-末端特异性放射免疫分析是 用于测定CCK免疫反应肽(CCK-IR)。 观察到与约800个碱基对应的单条mRNA带。 大鼠脑和脑组织Poly(A)+RNA的琼脂糖凝胶电泳法 与标记的前原CCK基因探针进行Northern印迹杂交。布赖恩 前原CCK mRNA在胚胎第14天时可检测到，并逐渐 在出生两周后增加到最高水平。它倾向于 成年大鼠略有下降。 在胚胎第14天检测不到CCK-IR，在胚胎第20天， 测量了可检测到的水平，但只有在 出生后第7天和第21天之间迅速增加的出生。由三个人 几周后，浓度达到成人水平的约90%。 特异性的信使核糖核酸的合成先于明显的合成和 神经递质多肽功能所需的储存机械。这个 胚胎第21天至成年期CCK mRNA/CCK-IR比值的变化规律 提示多肽的合成或储存在发育过程中会发生变化。

The expression of the gene coding for cholecystokinin (CCK) was studied pre- and post-natally in rat brain with a preproCCK specific cDNA probe to quantify mRNA. In addition, a c-terminal specific radioimmunoassay was used to measure CCK immunoreactive peptides (CCK-IR). A single band of mRNA corresponding to about 800 bases was observed after agarose gel electrophoresis of poly(A)+ RNA isolated from brain and Northern blot hybridization with the labeled preproCCK cDNA probe. Braine preproCCK mRNA was detectable by embryonic day 14 and progressively increased to reach maximum levels two weeks after birth. It tended to decrease slightly in adult rats. CCK-IR was undetectable at embryonic day 14. At embryonic day 20, detectable levels were measured but marked development was seen only after birth with a rapid increase between postnatal days 7 and 21. By three weeks, the concentration reached approximately 90% of the adult levels. Specific mRNA synthesis precedes pronounced appearance of the synthetic and storage machinery needed for neurotransmitter peptide function. The pattern of the ratio of CCK mRNA:CCK-IR from embryonic day 21 to adulthood suggests that synthesis or storage of the peptide alter during development.