FUNCTIONAL SIGNIFICANCE OF 16K PROLACTIN

催乳素(PRL)刺激靶细胞生长和功能 组织，如乳腺(MG)和前列腺，并可 导致乳腺癌和前列腺癌的发展。 然而，还没有发现循环之间存在明显的相关性 PRL水平(用放射免疫法测定；RIA)和 女性乳腺肿瘤的发病率和风险。如此缺乏 相关性可以用生物活性形式的存在来解释。 免疫活性低的PRL。我们已经分离出一种16K 由MG体外产生的PRL片段，具有较高的 生物测定：RIA比值。我们对16K PRL使用特定的RIA ，我们发现有相当数量的16K 催乳素存在于不同大鼠的循环中 生理状态。关于功能相关性的知识 MG将PRL蛋白分解为16K片段可添加 对催乳素在调节中的作用的认识 正常和癌变的乳腺生长。分析16K是否 在MG功能中扮演一个角色，我们将： A.通过测量酪蛋白合成来测试是否具有产乳活性 被大鼠乳腺细胞感染。 B.确定哪些组织可以产生卵裂和16K催乳素 以及产生率是否随 动物的生理状态。 C.检查各种组织中是否存在特定的受体 为了让16K PRL获得关于潜在目标器官的信息 碎片的碎片。 D.确定血清中的16K是单体、聚集态还是 航母已被限制。 E.用放射免疫法测定组织(脑下垂体、肝脏和 Mg)和不同生理状态MG大鼠的血清 生长和功能的状态，以及在化学- 诱发(DMBA)乳腺肿瘤。 16K催乳素也可在幼鼠的胃内产生 来自PRL的牛奶。我们发现，这些酶是 PRL的16K片段的蛋白质分解存在于牛奶中，并且 依赖于酸性的pH。研究是否存在16K PRL 并在护理青少年中起到一定的作用，我们将： A.测定胃奶和乳汁中的16K水平 哺乳大鼠的循环。 B.分析16K PRL被动免疫效果 对幼鼠生长速度的影响。 C.确定脑内是否存在特定的16K受体 幼鼠的各种组织。

Prolactin (PRL) stimulates the growth and function of target tissues such as the mammary gland (MG) and the prostate and may contribute to the development of breast and prostate cancer. However, no clear correlation has been found between circulating PRL levels (measured by radioimmunoassay; RIA) and the incidence and risk of mammary tumors in women. Such lack of correlation could be explained by the existence of bioactive forms of PRL with low immunoactivity. We have isolated a 16K fragment of PRL, generated in vitro by the MG, with a high bioassay: RIA ratio. Using a specific RIA for 16K PRL that we have developed, we have found that significant amounts of 16K PRL are present in the circulation of rats in different physiological states. Knowledge about the functional relevance of the proteolysis of PRL into the 16K fragment by the MG may add to the understanding of the role of PRL in the regulation of normal and cancerous mammary growth. To analyze whether 16K plays a role in MG function, we will: A. Test if for lactogenic activity by measuring casein synthesis by rat mammary cells. B. Determine which tissues can produce cleaved and 16K PRL in vitro and whether the rate of production varies with the physiological state of the animal. C. Survey various tissues for the presence of specific receptors for the 16K PRL to obtain information on potential target organs of the fragment. D. Determine whether 16K in serum is monomeric, aggregated or carrier bound. E. Measure by RIA the 16K levels in tissues (pituitary, liver and MG) and serum of rats whose MG are in different physiological states of growth and function, and in rats bearing chemically- induced (DMBA) mammary tumors. 16K PRL may also be produced inside the stomach of rat pups from the PRL in milk. We found that enzymes required for the proteolysis of PRL into the 16K fragment are present in milk, and dependent on an acid pH. To study whether 16K PRL is present and exerts some effect in the nursing young, we will: A. Determine the 16K levels in stomach milk and in the circulation of suckling rats. B. Analyze the effect of passive immunization against 16K PRL on the rate of growth of infant rats. C. Determine whether specific 16K receptors are present in various tissues of rat pups.