Thyroid hormone induction of an autocrine growth factor secreted by pituitary tumor cells

Thyroid hormones stimulate the rate of cell division by poorly understood mechanisms. The possibility that thyroid hormones increase cell growth by stimulating secretion of a growth factor was investigated. Thyroid hormones are nearly an absolute requirement for the division of GH4C1 rat pituitary tumor cells plated at low density. Conditioned media from cells grown with or without L-triiodothyronine (T3) were treated with an ion exchange resin to remove T3 and were tested for ability to stimulate the division of GH4C1 cells. Conditioned medium from T3-treated cells was as active as thyroid hormone at promoting GH4C1 cell growth but did not elicit other thyroid hormone responses, induction of growth hormone, and down-regulation of thyrotropin-releasing hormone receptors, as effectively as T3 did. A substance or substances associated with T3-induced growth stimulatory activity migrated at high molecular weight at neutral pH and was different from known growth-promoting hormones induced by T3. The results demonstrate that thyroid hormones stimulate the division of GH4C1 pituitary cells by stimulating the secretion of an autocrine growth factor.     

Arginine vasopressin as a thyrotropin-releasing hormone

Although hypothyroidism (with concomitant increased levels of thyroid-stimulating hormone) has been associated with elevated plasma vasopressin, the role that vasopressin plays in controlling thyroid-stimulating hormone secretion from the adenohypophysis is not understood. In two in vitro pituitary cell systems, vasopressin caused a specific and dose-related release of thyroid-stimulating hormone from cells that was equal in potency to that elicited by thyrotropin-releasing hormone, the primary acknowledged regulator of thyroid-stimulating hormone release. When injected into the hypothalamus, however, vasopressin specifically inhibited the release of thyroid-stimulating hormone. Thus, vasopressin may exert differential regulatory effects on thyroid-stimulating hormone secretion in the hypothalamus and pituitary gland.     

Ectopic pro-opiolipomelanocortin: sequence of cDNA coding for beta-melanocyte-stimulating hormone and beta-endorphin

A recombinant bacterial plasmid, pMS1, was constructed that contains 318 nucleotides complementary to a portion of pro-opiolipomelanocortin (proOLMC) messenger RNA from an ectopic adrenocorticotropin-producing tumor. The cloned complementary DNA insert, which contains the sequence that codes for all of the beta-melanocyte-stimulating hormone and beta-endorphin portions of proOLMC, as well as the 3' nontranslated section, is identical to the genomic sequence. Hybridization of tumor proOLMC complementary DNA to RNA subjected to electrophoresis and transferred to a nitrocellulose filter revealed two proOLMC messenger RNA species in the tumor polyadenylated RNA, but only one in pituitary polyadenylated RNA. At least one of the tumor proOLMC messenger RNA's is similar, if not identical, to human pituitary proOLMC messenger RNA.     

雷公藤内生真菌的分离鉴定及抗肿瘤活性菌株筛选

目的:从雷公藤根(Tripterygium wilfordii)茎及叶中分离鉴定内生真菌,并对其发酵产物进行体外抗肿瘤活性筛选。方法:采用微生物纯化方法分离雷公藤植物的内生真菌,根据菌落形态和显微特征对菌株进行分类鉴定。选用HCT-8(人结肠癌细胞)、Bel-7402(人肝癌细胞)、BGC823(人胃癌细胞)、A549(人肺癌细胞)为指标,采用MTT法对发酵产物进行体外抗肿瘤活性筛选。结果:从雷公藤不同器官中分离得到64株内生真菌,经形态观察鉴定为3目,5科,11属。其中5株内生真菌发酵产物对不同肿瘤细胞具有显著选择性细胞毒作用。结论:雷公藤内生真菌种类多样,具有很好的研究和应用价值。     

Identification of a thyroid hormone receptor that is pituitary-specific

Three cellular homologs of the v-erbA oncogene were previously identified in the rat; two of them encode high affinity receptors for the thyroid hormone triiodothyronine (T3). A rat complementary DNA clone encoding a T3 receptor form of the ErbA protein, called r-ErbA beta-2, was isolated. The r-ErbA beta-2 protein differs at its amino terminus from the previously described rat protein encoded by c-erbA beta and referred to as r-ErbA beta-1. Unlike the other members of the c-erbA proto-oncogene family, which have a wide tissue distribution, r-erbA beta-2 appears to be expressed only in the anterior pituitary gland. In addition, thyroid hormone downregulates r-erbA beta-2 messenger RNA but not r-erbA beta-1 messenger RNA in a pituitary tumor-derived cell line. The presence of a pituitary-specific form of the thyroid hormone receptor that may be selectively regulated by thyroid hormone could be important for the differential regulation of gene expression by T3 in the pituitary gland.     

雷公藤属内生真菌研究（Ⅱ） 昆明山海棠内生真菌的分离鉴定及抗肿瘤活性菌株筛选

为从昆明山海棠根及茎中分离鉴定内生真菌,并对其发酵产物乙酸乙酯提取物进行体外抗肿瘤活性筛选,采用微生物纯化方法,从昆明山海棠植物中分离得到内生真菌, 根据菌落形态和显微特征对菌株进行分类鉴定。选用Bel-7402（人肝癌细胞）、A549（人肺癌细胞）、BGC823（人胃癌细胞）、HCT-8（人结肠癌细胞）为指标,采用MTT法对发酵产物进行体外抗肿瘤活性筛选。结果表明,从昆明山海棠不同器官中分离得到37株内生真菌,经形态观察鉴定为2目、4科、8属。其中3株内生真菌发酵产物对不同肿瘤细胞具有显著选择性细胞毒作用。研究结果为国内首次从昆明山海棠植物中分离得到内生真菌,昆明山海棠内生真菌种类多样,具有潜在的研究和应用价值。     

Two mechanisms for the extinction of gene expression in hybrid cells

When two different mammalian cell types are fused to generate a stable hybrid cell line, genes that are active in only one of the parents are frequently shut off, a phenomenon called extinction. In this study two distinct, complementary mechanisms for such extinction of growth hormone gene expression were identified. In hybrids formed by fusing fibroblasts to pituitary cells, pituitary-specific proteins that bind to the growth hormone promoter were absent. In addition, a negative regulatory element located near the rat growth hormone promoter was specifically activated.     

猪生长激素启动子的克隆及功能分析

[目的]克隆猪生长激素启动子,确定其启动子核心序列和主要的顺式作用元件。[方法]根据NCBI上公布的序列设计引物,PCR扩增了猪生长激素5’端-1 821～+61 bp的序列,并通过移步缺失的方法,获得9段长短不一的启动子序列,将其分别构建到双荧光素酶表达载体pGL3-basic上。通过重组质粒瞬时转染大鼠垂体瘤细胞(GH3)、猪髋动脉血管内皮细胞(PIEC)和猪肾细胞(PK15)和转染后细胞荧光素酶活性的测定,检测这些5’末端缺失质粒在垂体及非垂体细胞中的相对转录活性。[结果]成功扩增了猪GH基因5’上游启动区1 882 bp的片段,并构建了9个pGL3-mGH promoter报告基因载体;双荧光素酶报告基因检测系统证实插入报告基因载体中的启动子具有非常强的细胞特异性。[结论]猪生长激素特异性在垂体细胞中表达,其最小启动子位于-110 bp以内,启动子区-218～-110 bp和-429～-218 bp间存在正向调控元件。     

猪生长激素启动子的克隆及功能分析(英文)

[目的]克隆猪生长激素启动子,确定其启动子核心序列和主要的顺式作用元件。[方法]根据NCBI上公布的序列设计引物,PCR扩增了猪生长激素5’端-1821~+61bp的序列,并通过移步缺失的方法,获得9段长短不一的启动子序列,将其分别构建到双荧光素酶表达载体pGL3-basic上。通过重组质粒瞬时转染大鼠垂体瘤细胞(GH3)、猪髋动脉血管内皮细胞(PIEC)和猪肾细胞(PK15)和转染后细胞荧光素酶活性的测定,检测这些5’末端缺失质粒在垂体及非垂体细胞中的相对转录活性。[结果]成功扩增了猪GH基因5’上游启动区1882bp的片段并构建了9个pGL3-mGHpromoter报告基因载体;双荧光素酶报告基因检测系统证实插入报告基因载体中的启动子具有非常强的细胞特异性。[结论]猪生长激素特异性在垂体细胞中表达,其最小启动子位于-110bp以内,启动子区-218~-110bp和-429~-218bp间存在正向调控元件。     

Parathyroid secretion: discovery of a major calcium-dependent protein

Bovine parathyroid tissue incubated in vitro secretes a protein that is distinct from both parathyroid hormone and proparathyroid hormone and comprises about 50 percent of the total secreted protein. This protein appears to be an aggregate consisting of two or more subunits of molecular weight 70,000 as determined by polyacrylamide gel electrophoresis in sodium dodecyl sulfate. Although the function of this protein is unknown, the secretion rates of both the protein and parathyroid hormone respond in parallel to changes in the concentration of calcium in the medium.     

Release of multiple hormones by a direct action of interleukin-1 on pituitary cells

Exposure to bacterial endotoxins has long been known to stimulate the release of anterior pituitary hormones; administration of endotoxin was at one time a common clinical test of anterior pituitary function. Endotoxin is a potent stimulus for production of the endogenous pyrogenic protein, interleukin-1 (IL-1), by macrophages and monocytes. The possibility that IL-1 has a direct effect on the secretion of hormones by rat pituitary cells in a monolayer culture was investigated. Recombinant human IL-1 beta stimulated the secretion of adrenocorticotropic hormone, luteinizing hormone, growth hormone, and thyroid-stimulating hormone. Increased hormone secretion into culture supernatants was found with IL-1 concentrations ranging from 10(-9) M to 10(-12) M. Prolactin secretion by the monolayers was inhibited by similar doses. These concentrations of IL-1 are within the range reported for IL-1 in serum, suggesting that IL-1 generated peripherally by mononuclear immune cells may act directly on anterior pituitary cells to modulate hormone secretion in vivo. Incubation of IL-1 solutions with antibody to IL-1 neutralized these actions. These pituitary effects of IL-1 suggest that this monokine may be an important regulator of the metabolic adaptations to infectious stressors.     

4株癌细胞产生一氧化氨水平的观察

目的：观察体外培养不同癌细胞系的一氧化氮生（ＮＯ）成量。方法：用Ｇｒｉｅｓｓ试剂测定癌细胞系经２４ｈ培养后一氧化氮的生成量。结果：不同癌细胞的ＮＯ产量不同,其中ＨＬ－６０细胞的产量最高,Ｋ５６２细胞次之,Ｈｅｌａ细胞产量最低。结论：ＮＯ的产量与癌细胞的种类、分化程度可能有一定关系。     

Epidermal growth factors enhances viral transformation of granulosa cells

Kirsten sarcoma virus produced a low incidence of transient morphological transformation in primary cultures of rat ovarian granulosa cells. In the presence of epidermal growth factor, the incidence of transient transformation increased severalfold and two continuous cell lines were established. Epidermal growth factor, a naturally occurring polypeptide hormone, appears to act here as a tumor promoter in the retrovirus-induced transformation of a mesodermally derived epithelium.     

Virus persists in beta cells of islets of Langerhans and is associated with chemical manifestations of diabetes

Molecular hybridization, monoclonal antibody, and electron microscopic analyses showed lymphocytic choriomeningitis virus (strains Armstrong and WE) persistently infecting cells of the islets of Langerhans in BALB/WEHI mice. When monoclonal or monospecific antibody conjugated with two different fluorochrome dyes was used to mark insulin-containing beta cells or viral antigens, viral nucleoprotein was identified predominantly in beta cells. Electron microscopy confirmed these findings by showing virions budding from the beta cells. Persistent infection was associated with chemical evidence of diabetes (hyperglycemia, abnormal glucose tolerance, and normal or low-normal concentrations of insulin). Concentrations of cortisol and insulin-like growth factor in blood were normal, as was the level of growth hormone in the pituitary gland. The virus-infected islet cells showed normal anatomy and cytomorphology. Neither cell lysis nor inflammatory infiltrates were routinely seen. Thus a virus may persistently infect islet cells and provide a biochemical and morphological picture comparable to that of early adult-onset diabetes mellitus in humans.     

两种入路显微手术治疗垂体瘤92例疗效对比分析

目的分析两种入路显微手术治疗垂体瘤的临床疗效，以探讨合理有效的手术方式．方法将分别采用经鼻、蝶窦入路和经颅人路手术的92例垂体瘤患者分为两组，对其疗效进行对比分析，并观察两组患者治疗后3～12个月的临床疗效．结果手术结果和随访显示：经鼻、蝶窦手术组患者的症状、视力、激素水平恢复情况均明显优于经颅手术组，肿瘤全切率及术后并发症情况亦较优，两组比较差异具有统计学意义（P〈0．05）．结论经鼻、蝶窦入路显微手术治疗垂体瘤是一种安全、有效的手术方法，且并发症少，有进一步临床应用价值．     

促性腺激素释放激素在不同品种母牛垂体中的免疫组化定位

为了掌握促性腺激素释放激素（GnRH）及其受体在不同品种母牛垂体中的变化规律,采用免疫组化SP染色法分别对广西沼泽型水牛、摩拉杂交水牛、荷斯坦奶牛、广西本地黄牛垂体中GnRH的分布表达进行对比研究。结果表明,不同品种母牛垂体中均发现有呈棕黄色或黄褐色的GnRH阳性物质存在,经Image-Pro Plus 6.0软件统计发现,摩拉杂交母水牛的GnRH免疫阳性细胞较其他3个品种的大（P〈0.05）,而平均光密度值介于荷斯坦母奶牛和广西本地母黄牛之间（P〉0.05）。在神经垂体中仅发现GnRH免疫阳性纤维,而未发现GnRH免疫阳性细胞;在腺垂体远侧部的细胞均呈GnRH免疫反应阳性,阳性物质主要分布在腺垂体远侧部嫌色细胞和嗜色细胞胞质内。说明GnRH对腺垂体激素分泌的调节可能是直接通过神经调节,而神经垂体可能只是GnRH调节过程的通路。     

稀有放线菌的选择性分离、鉴定及生物活性研究

聚乳酸(PLA)和丝蛋白粉分别作为选择性碳、氮源可以有效提高稀有放线菌的分离效率,同时海洋环境中蕴藏着丰富的活性稀有放线菌,是发现新药的有效途径。为了筛选并鉴定海洋环境中产生活性物质的稀有放线菌,以聚乳酸和丝蛋白粉分别作为选择性碳、氮源,配制6种分离培养基,用平板稀释法分离放线菌;并用滤纸片法和MTT法对供测菌株发酵产物进行活性筛选。结果表明:共分离出96株稀有放线菌,分属于11个属;其中,80株菌对7种靶标菌显示出一定的抗菌活性;78株菌对肿瘤细胞具有不同程度的细胞毒活性。另外,比较了6种培养基对稀有放线菌的分离效果。从分离结果来看,最理想的是聚乳酸培养基。     

Thyroid hormone action: a cell-culture system responsive to physiological concentrations of thyroid hormones

Cells from a rat pituitary tumor cell line will respond in vitro to physiological concentrations of L-thyroxine and L-triiodothyronine. The cells are grown in a cultutre medium that contains serum from a hypothyroid calf. Dose-response relationships of a vacriety of thyronine derivatives indicate that this system has a specificity of response which is similar to that observed in vitro.