A STUDY OF HORMONAL FACTORS WHICH INFLUENCE THE PRODUCTION OF INSULIN

1. Insulinotropic effects were obtained with a protein fraction of the anterior pituitary, with estradiol and with stilbestrol. 2. Varying diabetogenic effects were obtained with highly purified prolactin preparations, with progesterone, with testosterone and with a fraction, probably also protein, from the anterior pituitary.     

Sulfhydryl groups and estradiol-receptor interaction

The characteristic ability of rat uteri to take up tritiated estradiol in vitro or to retain estradiol previously incorporated either in vivo or in vitro is destroyed by treating the tissue with various sulfhydryl-blocking reagents. The two radioactive estradiol-receptor complexes, observed in uterine homogenates in the supernatant fraction and in an extract of the nuclear fraction, respectively, are disrupted by brief exposure to organic mercurials in the cold. Sulfhydryl groups of uterine receptor substances apparently play a vital role in estradiol binding, perhaps indirectly through contribution to receptor conformation.     

二氢吡啶(Diludin)对产蛋鸡内分泌的影响

１ ０２４羽３００日龄罗曼蛋鸡随机分４组,分别饲喂二氢吡啶（Ｄｉｌｕｄｉｎ）添加量０,１００,１５０,２００ ｍｇ／ｋｇ的４种饲粮,于饲喂后第３０日和第８０日采血和屠宰,研究其对蛋鸡内分泌功能的影响。结果显 示：Ｄｉｌｕｄｉｎ均显著地提高了腺垂体和血清中ＦＳＨ,ＬＨ含量,其中垂体ＦＳＨ和ＬＨ含量随饲喂剂量提高 而增加,血清ＦＳＨ和ＬＨ含量以１５０ ｍｇ／ｋｇ组效果最佳;Ｄｉｌｕｄｉｎ提高了血清Ｔ３含量,Ｔ４差异不显著, ３０日Ｔ３随饲粮中Ｄｉｌｕｄｉｎ递增而增加,８０日１５０,２００ ｍｇ／ｋｇ组与对照组差异显著;饲粮中添加Ｄｉｌｕｄｉｎ 具有改进血清雌二醇（Ｅ２）水平,其中８０ 日 １５０,２００ ｍｇ／ｋｇ组与对照组差异显著;１５０ ｍｇ／ｋｇ Ｄｉｌｕｄｉｎ显 著提高血清中孕酮（Ｐ４）含量;饲粮中添Ｄｉｌｕｄｉｎ显著提高下丘脑和腺垂体中ｃＡＭＰ含量。     

鸡胚垂体生长激素细胞的发生及其变化

为研究鸡胚垂体中生长激素细胞的发生及其在发育过程中的变化 ,分别在鸡胚发育的第 3 5～ 2 0 5天采集鸡胚垂体 ,用免疫组织化学方法研究鸡胚垂体中生长激素细胞的发生和细胞形态、数量、在垂体中的分布特点和在发育过程中的变化。结果表明 ,鸡胚发育中期第 9 5天可观察到少量的生长激素阳性细胞散在分布于垂体后叶 ,细胞多排列成索状或团状 ,细胞之间边界不清 ,细胞核较大。在鸡胚发育的第 12 5天以后 ,生长激素细胞的细胞浆与细胞核比值逐渐变小 ,且均匀分布于腺垂体的后叶。生长激素细胞数在鸡胚发育的第 12 5天之后显著升高 (P <0 0 1) ,在鸡胚发育的第 16 5天 ,生长激素细胞占垂体细胞总数的 9 4 %。以上结果证明鸡胚垂体中生长激素细胞增殖和分化过程主要发生在发育的中期至出壳之前 ,而生长激素细胞的分泌功能在鸡胚发育的后期最为活跃。     

Pituitary gonadotrophs: nuclear concentration of radioactivity after injection of ( 3 H)testosterone

Gonadotrophs and castration cells in the male rat pituitary showed nuclear concentration of radioactivity 1 hour after [1,2,6,7-(3)H]testosterone injection. Thyrotrophs and acidophils did not retain radioactivity; also the cells of the intermediate and posterior lobes did not accumulate radioactivity. The autoradiographic results suggest a direct and selective action of androgen on gonadotrophs, which contrasts with the action of estradiol which was shown earlier to bind not only to basophils but to acidophils and chromophobes as well.     

miRNA-181b在牛腺垂体中的表达规律及其调控作用研究

[目的]探索m iRNA-181b在成熟（18月龄）和未成熟（1月龄）牛腺垂体中差异表达量及其调控功能。[方法]通过构建成熟（18月龄）和未成熟（1月龄）的延边黄牛腺垂体组织m iRNA cDNA文库,对文库中的m iRNA进行Solexa高通量深度测序,并对公牛腺垂体中的m iRNA进行鉴别。从测序结果中挑选出具有差异表达的m iRNA-181b,经实时荧光定量PCR验证其在不同发育期延边黄牛腺垂体中的表达规律,并通过TargetScanS预测m iRNA-181b的靶基因。[结果]m iRNA-181b在不同发育期牛腺垂体表达量存在显著差异,1月龄公牛腺垂体中m iRNA-181b表达量是18月龄的4.05倍。m iRNA-181b与FSHβ基因3＇非编码区838~844碱基可能是特异结合,其结合碱基为UGAAUGUA。[结论]该试验为FSHβ的转录后调控研究提供了理论依据。     

miRNA-181b在牛腺垂体中的表达规律及其调控作用研究(英文)

[目的]探索miRNA-181b在成熟(18月龄)和未成熟(1月龄)牛腺垂体中差异表达量及其调控功能。[方法]通过构建成熟(18月龄)和未成熟(1月龄)的延边黄牛腺垂体组织miRNAcDNA文库,对文库中的miRNA进行Solexa高通量深度测序,并对公牛腺垂体中的miRNA进行鉴别。从测序结果中挑选出具有差异表达的miRNA-181b,经实时荧光定量PCR验证其在不同发育期延边黄牛腺垂体中的表达规律,并通过TargetScanS预测miRNA-181b的靶基因。[结果]miRNA-181b在不同发育期牛腺垂体表达量存在显著差异,1月龄公牛腺垂体中miRNA-181b表达量是18月龄的4.05倍。miRNA181b与FSHβ基因3 非编码区838 ~844碱基可能是特异结合,其结合碱基为UGAAUGUA。[结论]该研究为FSHβ的转录后调控研究提供了理论依据。     

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.     

Induced expression of the glucocorticoid receptor in the rat intermediate pituitary lobe

Synthesis and release of pro-opiomelanocortin-derived peptides are under differential regulation in the anterior and intermediate lobes of the pituitary. Glucocorticoids inhibit synthesis of pro-opiomelanocortin-related peptides in the anterior lobe but not in the intermediate lobe. These two lobes are also characterized by differences in neural innervation and blood flow, both of which may represent routes of access for regulatory factors (the intermediate lobe is avascular). Immunoreactive glucocorticoid receptor, which can be demonstrated in many tissues, is absent from the intermediate lobe. Immunocytochemistry was used to demonstrate the presence of immunoreactive glucocorticoid receptor in the intermediate lobe after pituitary stalk transection, neurointermediate lobe grafts to kidney capsule, or monolayer culture of neurointermediate pituitary cells. This appearance of the glucocorticoid receptor is presumably a consequence of removal of intermediate pituitary cells from neural influences that may be responsible for inhibiting their expression under normal conditions in vivo.     

Beta-adrenergic mechanism of insulin-induced adrenocorticotropin release from the anterior pituitary

Intraperitoneal administration of insulin to control rats and to rats with pituitary stalk transections or with lesions of the median eminence resulted in increased plasma adrenocorticotropin (ACTH) levels. The insulin-induced stimulation of ACTH release was blocked in both the control and lesioned animals by prior treatment with either the beta-adrenergic antagonist propranolol or the glucocorticoid analog dexamethasone. The direct application of insulin to primary cultures of the anterior pituitary did not evoke ACTH release or affect the maximal ability of corticotropin-releasing factor or epinephrine to stimulate ACTH secretion. The results suggest that insulin stimulates ACTH release by a mechanism in which catecholamines of peripheral origin act directly on the anterior pituitary.     

甲低大鼠垂体前叶内IFN-γ样免疫反应阳性物质的表达

应用免疫组织化学(SP)法结合H2O2-DAB黄色呈色法进行显色。IFN-γ样免疫反应阳性物质位于细胞的胞浆内,其阳性细胞只分布于垂体前叶,而后叶和中间部未见免疫反应阳性物质;对照组均未发现免疫反应阳性细胞。甲状腺素低下可以诱导大鼠垂体前叶内IFN-γ样免疫阳性物质的表达,提示甲状腺素低下会影响垂体前叶的内分泌功能。     

1 alpha, 25-Dihydroxyvitamin D3 nuclear receptors in pituitary

Specific binding of 1 alpha,25-dihydroxyvitamin D(3) was found in nuclear and cytosol fractions of the bovine pituitary. For nuclear binding. the dissociation constant was 0.1 namomole per liter, and maximum binding was 104 femtomoles per milligram of protein. In competition studies, 25-hydroxyvitamin D(3) was 300 times weaker than 1 alpha,25-dihydroxyvitamin D(3). The existence of high-affinity sites supports a physiologic role for 1 alpha,25-dihydroxyvitamin D(3) in the pituitary.     

Pituitary intermediate lobe in dog: two cell types and high bioactive adrenocorticotropin content

The pituitary intermediate lobe of most species is cytologically monotonous, but that of the dog is composed of two immunocytochemically distinct cell types. The predominant A cells are typical pars intermedia cells: they stain immunocytochemically for alpha-melanotropin and, more weakly, for adrenocorticotropin and beta-lipotropin. The B cells are like the corticotrophs of the anterior lobe: they stain intensely for adrenocorticotropin and beta-lipotropin but not for alpha-melanotropin. The B cells may account for the high concentration of bioactive adrenocorticotropin measured in the canine pars intermedia, and may explain why in dogs adenomas causing Cushing's disease through hypersecretion of adrenocorticotropin can arise from the intermediate as well as the anterior pituitary lobe.     

Gonadotroph-specific expression of metallothionein fusion genes in pituitaries of transgenic mice

Transgenic mice expressing a metallothionein-somatostatin fusion gene contain high concentrations of somatostatin in the anterior pituitary gland, a tissue that does not normally produce somatostatin. Immunoreactive somatostatin within the anterior pituitaries was found exclusively within gonadotrophs. Similarly, a metallothionein-human growth-hormone fusion gene was also expressed selectively in gonadotrophs. It is proposed that sequences common to the two fusion genes are responsible for the gonadotroph-specific expression.     

Endothelin: a novel peptide in the posterior pituitary system

Endothelin (ET), originally characterized as a 21-residue vasoconstrictor peptide from endothelial cells, is present in the porcine spinal cord and may act as a neuropeptide. Endothelin-like immunoreactivity has now been demonstrated by immunohistochemistry in the paraventricular and supraoptic nuclear neurons and their terminals in the posterior pituitary of the pig and the rat. The presence of ET in the porcine hypothalamus was confirmed by reversed-phase high-pressure liquid chromatography and radioimmunoassay. Moreover, in situ hybridization demonstrated ET messenger RNA in porcine paraventricular nuclear neurons. Endothelin-like immunoreactive products in the posterior pituitary of the rat were depleted by water deprivation, suggesting a release of ET under physiological conditions. These findings indicate that ET is synthesized in the posterior pituitary system and may be involved in neurosecretory functions.     

牦牛生长激素基因分子特性分析

设计特异性引物,利用RT-PCR方法从牦牛脑垂体中扩增出生长激素基因(YGH)编码区全序列,并进行分子特性分析.结果表明:牦牛生长激素基因编码区全长654 bp,包含一个完整的阅读框,编码217个氨基酸.采用生物信息学方法对分子特性进行分析表明:动物生长激素基因在进化上非常保守,牦牛生长激素基因氨基酸序列与黄牛、山羊、绵羊、马、猪、猫和犬的同源性分别为100%、99.1%、98.6%、88.9%8、8.5%、88.9%和89.4%.牦牛生长激素蛋白有2个明显的疏水区域,存在2个强跨膜区和信号肽,是一种分泌型蛋白质,二级结构主要以α-螺旋和不规则卷曲为主,三级结构包含第28-215位氨基酸残基;牦牛生长激素蛋白有较高的抗原指数和抗原表位,这与YGH编码蛋白具有良好的抗原性相一致.     

雌二醇及其受体在北方山溪鲵精巢中的周期性分布

用免疫组织化学方法检测雌二醇(estradiol)及其受体(estrogen receptor)在北方山溪鲵(Batrachuperus tibetanus)精巢发育周期中的表达变化。结果表明,在4~5月,雌二醇及受体在精原细胞的胞质中强表达;6月,雌二醇在精母细胞的胞质中表达较弱,其受体在精母细胞的核质中有较强表达;7月,雌二醇及受体在精子细胞的胞质中表达;8月,雌二醇及受体在精原细胞的胞质中和变态后的精子头部有弱表达;9-11月,两者均在精原细胞的胞质中及精子头部有较强表达。说明雌二醇及其受体存在于整个精巢周期中,二者在生精细胞中的强弱变化基本一致,其变化规律与精子发育周期密切相关;雌激素受体多存在于生精细胞的胞质中,雌激素可能以非基因组效应调控细胞的增殖,并与精子的发育成熟密切相关。     

GHS-R1a在大鼠下丘脑-垂体-卵巢轴上的定位及其mRNA的周期性表达

取成年SD大鼠的下丘脑、垂体、卵巢组织制成石蜡切片,采用PV-9000两步法免疫组织化学检测GHS-R1a在下丘脑-垂体-卵巢轴上的定位.实时荧光定量PCR检测GHS-Rla mRNA在不同发情周期大鼠F丘脑-垂体-卵巢轴上的表达.结果表明:GHS-R1a主要分布在下丘脑的弓状核、腹内侧核、正中隆起等,腺垂体的嗜色细胞...