小鼠子宫内膜LIF基因表达与雌、孕激素的关系

白血病抑制因子（LIF）是一种多功能活性的糖蛋白,LIF基因在大多数妊娠第4天的小鼠子宫内膜进行着强烈的表达,然而LIF基因表达调控的机制目前尚不清楚。本实验对168只妊娠第4~5天的小鼠LIF基因表达和血清中雌、孕激素水平分别进行了检测,发现18只小鼠无LIF基因表达,其血清中雌、孕激素水平分别极显著（P＜0.01）和显著（0.01＜P＜0.05）低于其他表达的小鼠。提示：雌、孕激素对小鼠LIF基因表达过程中起着一定的作用,将为LIF基因表达调控机制的深入研究打下基础。     

多代驯化对布氏田鼠非繁殖期性激素本底水平的影响

为阐明驯化过程对季节性繁殖的布氏田鼠Lasiopodomys brandtii性腺活性的影响,采用放射免疫技术从秋季（11月）至翌年春季（3月）对室内驯化1月、3年和10年的雌雄鼠粪便中的性激素水平进行监测。结果显示,在11—12月非繁殖季节,驯化10年组雄鼠睾酮水平分别达到3年组和1月组的3.5倍和13.3倍,驯化10年组雌鼠雌二醇水平分别达到3年组和1月组的2.0倍和3.7倍,且差异均达到显著水平;长期（3年和10年）驯化组雄鼠在繁殖初期（1—3月）的睾酮水平也较短期驯化组显示出更大幅度的提升。表明在经历长期驯化后布氏田鼠对稳定的室内环境逐渐适应,非繁殖期性腺活性抑制的程度逐渐减弱,呈现出随驯化时长增加而逐渐递增的趋势,从而导致鼠类繁殖表型发生了可塑性变化。     

A New β-Estradiol-lnducible Vector Set that Facilitates Easy Construction and Efficient Expression of Transgenes Reveals CBL3-Dependent Cytoplasm to Tonoplast Translocation of CIPK5

Transient and stable expression of transgenes is central to many investigations in plant biology research. Chemical regulation of expression can circumvent problems of plant lethality caused by constitutive overexpression or allow inducible knock （out/down） approaches. Several chemically inducible or repressible systems have been described and successfully applied. However, cloning and application-specific modification of most available inducible expression systems have been limited and remained complicated due to restricted cloning options. Here we describe a new set of 57 vectors that enable transgene expression in transiently or stably transformed cells. All vectors harbor a synthetically optimized XVE expression cassette, allowing I~-estradiol mediated protein expression. Plasmids are equipped with the reporter genes GUS, GFP, mCherry, or with HA and Strepll epitope tags and harbor an optimized multiple cloning site for flexible and simple clon- ing strategies. Moreover, the vector design allows simple substitution of the driving promoter to achieve tissue-specificity or to modulate expression ranges of inducible transgene expression. We report details of the kinetics and dose-dependence of expression induction in Arabidopsis leaf mesophyll protoplasts, transiently transformed Nicotiana benthamiana leaves, and stably transformed Arabidopsis plants. Using these vectors, we investigated the influence of CBL （Calcineurin B-like） protein expression on the subcellular localization of CIPKs （Calcineurin B-like interacting protein kinases）. These analyses uncovered that induced co-expression of CBL3 is fully sufficient for dynamic translocation of CIPK5 from the cytoplasm to the tonoplast. Thus, the vector system presented here facilitates a broad range of research applications.     

性激素对大鼠诱发肝癌中胎盘型谷胱甘肽S-转移酶(GST-P)表达的影响

本实验利用Solt-Farber顺序诱发大鼠肝癌,观察肝组织中GST活性及GST-P含量在化学诱癌中的变化,并观察性激素对大鼠化学诱发肝癌的早期病变中GST-P表达的作用。结果显示无论是GST活性或GST-P的含量,在诱癌至第三周开始升高,第五周升至最高。利用此模式,选择诱癌至第五周,免疫组化法检测各种处理后肝组织中GST-P的表达。发现睾丸假切除的雄性大鼠经化学诱癌后,肝中有高的GST-P表达,睾丸假切除的雄性大鼠诱癌合并雌二醇处理,明显降低肝组织GST-P阳性灶的面积和数量;合并睾丸酮处理,虽减少GST-P阳性灶的面积,但其数量略有升高。与睾丸假切除后诱癌的雄性大鼠相比,切除睾丸的大鼠经诱癌,有更低的GST-P阳性灶的面积;睾丸切除合并雌二醇处理,GST-P阳性灶的面积进一步降低。与仅化学诱癌的卵巢假切除雌性大鼠比,卵巢切除鼠诱癌后,GST-P阳性灶的面积稍有增加;对卵巢切除合用睾丸酮的大鼠诱癌,阳性灶的面积进一部增加。无论性腺切除与否,雄性大鼠比雌性大鼠有更高的GST-P表达。这些结果提示雌激素可抑制而雄激素则可促进化学诱癌大鼠肝中GST-P的表达。这一结果可能与临床上男性较女性易患肝癌有关。     

Cellular localization of the receptor-dependent and receptor-independent uptake of human LDL in the liver of normal and 17 alpha-ethinyl estradiol-treated rats

The cellular localization in the liver of the receptor-dependent and -independent uptake of human low density lipoprotein (LDL) in normal and 17 alpha-ethinyl estradiol-treated rats was investigated by the simultaneous in vivo injection of human 131I-LDL and human reductive methylated 125I-LDL. The cells were subsequently isolated by a low temperature method. In untreated rats, after 30 min of in vivo circulation of human LDL, 57% of the receptor-dependent liver-association of human LDL occurs in non-parenchymal cells and 43% in parenchymal cells. Estradiol treatment of rats for 3 days selectively increases the receptor-dependent cell-association of human LDL with hepatocytes (17-fold), while the receptor-dependent cell-association with non-parenchymal cells is not affected.     

Gonadal hormones in experimental Ancylostoma caninum infections in male Swiss albino mice

Ismail Bhai and Pandey A. K. 1982. Gonadal hormones in experimental Ancylostoma caninum infections in male Swiss albino mice. International Journal for Parasitology12: 589–591. Orchiectomy in mice increased their resistance to Ancylostoma caninum infection. Testosterone propionate increased the susceptibility of castrated animals to infection and also increased the survival of larvae in muscles, compared with sham-operated placebo-treated controls with intact testes. Estradiol benzoate increased the resistance of castrated mice as demonstrated by differential larval recoveries. The possible involvement of the small intestine as a barrier to infection and the influence of testosterone on host susceptibility to infection is discussed.     

Estrogen increases calcitonin gene‐related peptide‐immunoreactive sensory innervation of rat mammary gland

Estrogen plays important roles in preparing mammary tissue for lactation. However, estrogen also influences innervation in some tissues. We examined the effect of estrogen on peripheral innervation of mammary tissues of ovariectomized adult virgin female rats. Seven days after ovariectomy, 17β‐estradiol or placebo pellets were implanted subcutaneously, and tissues were harvested 1 week later. Estrogen treatment decreased mammary gland mass and adipocyte content, while ductal content increased and vascular composition was unaffected. Estrogen increased total areas occupied by nerves in mammary gland sections immunostained for the pan‐neuronal marker protein gene product 9.5, and this increase persisted after normalizing for treatment‐induced differences in gland mass. Although a significant increase in tyrosine hydroxylase‐immunoreactive sympathetic nerve area was observed, no difference was detected following correction for differences in gland size, implying a conserved number of sympathetic nerves in the face of reduced gland volume. Calcitonin gene‐related peptide‐immunoreactive sensory nerve sectional area was also increased, and corrected nerve area remained 88% greater, indicating nerve proliferation during estrogen treatment. Total, sensory, and sympathetic innervation of the nipple and adjacent dermal tissue were unaffected by estrogen. We conclude that chronic estrogen elevation induces selective proliferation of rat mammary gland calcitonin gene‐related peptide‐containing nerves, which are associated primarily with blood vessels and are probably nociceptors. Because they are likely to subserve a vasodilatory function, increased innervation may promote increased blood flow necessary for milk formation during suckling. Moreover, these findings may help explain abundant anecdotal reports of increased breast sensitivity in humans under high estrogen conditions. © 2004 Wiley Periodicals, Inc. J Neurobiol 59: 192–204, 2004     

Regional alterations in brain amino acids during the estrous cycle of the rat

Concentrations of 11 amino acids, including the neurotransmitters GABA, glutamate, aspartate, glycine and taurine, were determined in 12 brain regions of female rats during different stages of the estrous cycle. In addition, amino acids and sex hormone levels were determined in plasma. All sample collections were done in the forenoon between 9 and 11 a.m. Most regional amino acid levels measured did not change signficantly during estrous cycle, but significant alterations were found for GABA and glutamate in hypothalamus. Both amino acids were slightly decreased in hypothalamus during proestrus, which might reflect an alteration of GABA turnover in response to the high estrogen levels during this stage. A decreased glutamate level during proestrus was also found in thalamus, while both glutamate and GABA did not vary throughout estrous cycle in any of the other examined regions, including substantia nigra, amygdala, striatum, cortex and hippocampus. When diestrus was subdivided according to progesterone levels, high levels of this hormone seemed to be associated with effects on metabolism of certain amino acids, including glycine in substantia nigra, alanine in thalamus and threonine in pons/medulla. However, the few changes in regional amino acid concentrations found during the estrous cycle were so small that the functional significance of these changes cannot be ascertained without further determination of the cellular or subcellular compartments of brain tissue involved.