PITUITARY KALLIKREIN & PROHORMONE PROCESSING

组织(腺体)激肽释放酶(TK)是一种胰酶样丝氨酸 一种能产生生物活性多肽的蛋白酶 非活性前体具有很高的特异性。我最近有过 在大鼠脑垂体中发现了TK，并发现TK展示了 组织特异性表达模式与生理调节 中间体中的MSH和β-内啡肽密切平行 垂体前叶(AP)的催乳素(PRL)。这个 拟议的研究将考察传统知识在翻译后翻译中的作用 催乳素在AP中的处理，以及阿片黑色素原(POMC； MSH和β-内啡肽的前体)位于中间叶。大鼠 脑垂体TK的提纯及其理化和酶学性质 与来自其他组织的TK的特性进行比较。传统知识的能力 用凝胶电泳法检测PRL和POMC的裂解 和高效液相色谱分析，以及通过微测序鉴定的切割位点。PRL TK加工可能会产生新的激素，具有重要的 在生殖生物学和乳房生长中的作用。因此， 将对PRL裂解产物进行生物检测，以确定其经典的PRL作用 产乳酶的诱导和Nb2的刺激 淋巴瘤细胞生长)，以及对大鼠的新的促分裂作用 活体内的乳腺。细胞和亚细胞定位 TK和切割的催乳素在大鼠脑垂体中的表达 免疫组织化学和亚细胞分级以确定TK是否 定位于激素前体的加工部位。TK、PRL的变化 并将比较POMC水平、生物合成和分泌 在经历了各种生理、激素和药物治疗后 以确定它们在体内和体外有多紧密 监管是相互关联的。大鼠脑下垂体的替代功能 将测试TK(例如，激动素的产生和激动素的调制 脑下垂体激素释放)。结果将决定TK是否 处理激肽以外的多肽的功能，可能会阐明 激素生物合成的重要机制，并揭示了一种新的 PRL折叠中间体的作用。一种雌激素的演示- 产生具有新的有丝分裂原的PRL片段的诱导途径 乳腺上的活动可能对 目前荷尔蒙控制乳房生长的理论和 大鼠和人的肿瘤发生。

Tissue (glandular) kallikrein (TK) is a trypsin-like serine protease which can generate biologically active peptides from inactive precursors with high specificity. I have recently discovered TK in the rat pituitary, and have found that TK exhibits patterns of tissue specific expression and physiological regulation closely paralleling MSH and beta-endorphin in the intermediate lobe, and prolactin (PRL) in the anterior pituitary lobe (AP). The proposed research will examine TK's role in the posttranslational processing of PRL in the AP, and Pro-opiomelanocortin (POMC; the precursor to MSH and beta-endorphin) in the intermediate lobe. Rat pituitary TK will be purified and its physiochemical and enzymatic properties compared to TK from other tissues. The ability of TK to cleave PRL and POMC will be examined using gel-electrophoresis and HPLC, and cleavage sites identified by microsequencing. PRL processing by TK may result in novel hormones with important functions in reproductive biology and mammary growth. Therefore, PRL cleavage products will be bioassayed for classic PRL actions (induction of milk-producing enzymes and stimulation of Nb2 lymphoma cell growth), as well as novel mitogenic actions on rat mammary glands in vivo. The cellular and subcellular localization of TK and cleaved PRL in the rat pituitary will be examined using immunohistochemistry and subcellular fractionation to see if TK is localized in sites of prohormone processing. Changes in TK, PRL and POMC levels, biosynthesis, and secretion will be compared following various physiological, hormonal and pharmacological in vivo and in vivo and in vitro to determine how tightly their regulation is interlinked. Alternative functions for rat pituitary TK will be tested (e.g., kinin generation and kinin modulation of pituitary hormone release). The results will determine whether TK functions to process peptides other than kinins, may elucidate an important mechanism of hormone biosynthesis, and reveal a novel role for PRL folding intermediates. Demonstration of an estrogen- induced pathway for generating PRL fragments with novel mitogenic activity on the mammary gland may be of considerable importance to current theories of the hormonal control of mammary growth and tumorigenesis in both rats and man.