PITUITARY KALLIKREIN & PROHORMONE PROCESSING

组织（腺）激肽释放酶（TK）是一种胰蛋白酶样丝氨酸 一种蛋白酶，其可以从 具有高特异性的非活性前体。 我最近 在大鼠脑垂体中发现了TK，并发现TK表现出 组织特异性表达和生理调节模式 与中间的MSH和β-内啡肽密切相关 垂体前叶（AP）中的催乳素（PRL）。 的 拟议的研究将探讨传统知识的作用，在翻译后 AP中PRL的加工，以及前阿黑皮素（POMC; MSH和β-内啡肽的前体）。 大鼠 垂体TK将被纯化，并且其理化和酶学性质将被改变。 与其他组织的TK相比， TK的能力 将使用凝胶电泳检测切割PRL和POMC的能力 和HPLC，并通过微测序鉴定切割位点。 PRL TK的加工可能会产生新的激素， 在生殖生物学和乳腺生长中的作用。 因此，我们认为， 将对PRL裂解产物的经典PRL作用进行生物测定 （诱导产乳酶和刺激Nb 2 淋巴瘤细胞生长），以及对大鼠的新的促有丝分裂作用 体内乳腺。 细胞和亚细胞定位 将使用以下方法检查大鼠垂体中TK和切割的PRL 免疫组织化学和亚细胞分级，看看TK是否 定位于激素原加工部位。 TK、PRL的变化 和POMC水平，生物合成和分泌将进行比较 在各种生理、激素和药理学方面， 在体内和体外，以确定他们的紧密程度， 监管是相互关联的。 大鼠垂体的替代功能 将测试TK（例如，激肽产生和激肽调节 垂体激素释放）。结果将决定TK是否 功能，加工肽以外的激肽，可以阐明一个 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。 雌激素的证明- 产生具有新促有丝分裂活性的PRL片段的诱导途径 对乳腺的活动可能相当重要， 目前关于激素控制乳房生长的理论， 在老鼠和人身上的肿瘤发生。

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.