重度联合免疫缺陷（SCID）小鼠排卵,胚胎发育能力及妊娠母体激素动态

为探讨先天性Ｔ－Ｂ淋巴细胞联合缺陷对生殖功能的影响，用正常ＢＡＬＢ／ｃ小鼠作对照，对重度联合免疫缺陷（ＳＣＩＤ）小鼠的排卵，胚胎（胎儿）发育能力及妊娠体外周血浆促黄体素（ＬＨ）和孕酮（Ｐ）水平的变化进行了研究。首先，观察了妊娠期、窝产仔数，发现ＳＣＩＤ小鼠大多在妊娠第２０天（检栓当天为第１天）凌晨分娩，平均窝产卫数为３．８６±１．６７）只，ＢＡＬＢ／Ｃ小鼠多在妊娠第２０天较晚或第２１天凌晨分娩，平     

小鼠繁殖行为的观察与分析

为提高实验室用小鼠的繁殖率,对其饲养过程中的繁殖行为进行了研究。结果表明,发情周期的鉴定是提高小鼠受孕率的关键,阴道栓是实验室小鼠交配受孕鉴定的依据。小鼠性成熟早,6周龄的雄鼠附睾中就有运动活泼的精子,雌鼠在6周龄即可发情排卵、受孕。     

利用胚胎移植技术建立SPF小鼠群

无特异病原体（ＳｐｅｃｉｆｉｃＰａｔｈｏｇｅｎＦｒｅｅ，ＳＰＦ）动物指体内外无特定微生物和寄生虫的动物，因为它排除了实验动物本身的传染病原及寄生虫，实验结果准确、可靠，在生物医学各个领域研究中得到广泛的应用，是现代实验动物科学的标志。通过剖腹产或药物净化可获得ＳＰＦ小鼠，但这两种方法有很多缺陷：剖腹产准确手术时间难以掌握，而且所得到的乳鼠要经代乳饲喂，成活率低，一些病毒（如淋巴细胞脉络丛脑膜炎病毒）可通过胎盘传给仔鼠，达不到净化效果。药物净化法一般很难达到ＳＰＦ级。本研究建立了一种通过胚胎移植技术获得ＳＰＦ小鼠的方法。具体是在无菌条件下，将普通级Ｃ５７ＢＬ／６Ｊ近交系小鼠胚胎冲取出来，移植给ＳＰＦ级ＮＩＨ封闭群雌鼠，这样ＳＰＦ级受体鼠ＮＩＨ可出生ＳＰＦ级Ｃ５７ＢＬ／６Ｊ仔鼠，通过这一方法可将普通级Ｃ５７ＢＬ／６Ｊ小鼠直接净化达到ＳＰＦ级。在无菌条件获得普通级近交系Ｃ５７ＢＬ／６Ｊ小鼠胚胎７５枚，分别移植给同期假孕ＳＰＦ级ＮＩＨ小鼠，共生产２８只Ｃ５７ＢＬ／６Ｊ小鼠，胚胎移植成活率３７．３％。乳鼠在隔离器内饲养，后经微生物及遗传检测，普通级Ｃ５７ＢＬ／６Ｊ小鼠经胚胎移植后达到ＳＰＦ级。     

孕马血清促性腺激素单克隆抗体的研制

用高纯度孕马血清促性腺激素免疫ＢＡＬＢ／ｃ小鼠，加完全佐剂进行基础免疫，第７日脾脏免疫，第１０日取血测滴度，为阳性则取出脾脏，将脾细胞与Ｓｐ２／０细胞融合，培养并用琼脂单扩法筛选抗体生成孔，ＥＬＩＳＡ复测，得孕马血清促性腺激素抗体阳性杂交瘤细胞株Ｄ６Ｃ１０。经降植烷予处理的ＢＡＬＢ／ｃ鼠腹腔注射Ｄ６Ｃ１０，腹水单抗滴度１０＾６。瘤细胞ＤＮＡ含量测定证实为脾和骨髓瘤细胞的杂交瘤细胞。单抗亚型分析为Ｉ     

H-Y抗血清的制备及检测研究

选用８ ～１２ 周龄纯系的 Ｂ Ａ Ｌ Ｂ／ Ｃ 母鼠， 用同日龄的 Ｂ Ａ Ｌ Ｂ／ Ｃ 公鼠采取皮肤移植和脾细胞注射２ 种方式免疫， 制备 Ｈ Ｙ 抗血清， 经精子微量细胞毒性试验， 筛选抗血清。皮肤移植５ 只小鼠中只有１ 只产生较好的抗血清， 脾细胞注射的４ 只小鼠都能产生较好的抗血清， 产生抗血清的小鼠占５５ ％ 。抗血清与昆明鼠正常８ｃｅｌｌ 早期桑椹胚培养５ ～６ 、１８ 和２４ ｈ 后， 退化率达４３３ ％ ， 经 Ｘ２ 检验差异不显著（ Ｐ ＞ ００５） ， 符合自然性比例。     

AMMS／13近交系小鼠的培育及其生物学特性

ＡＭＭＳ／１３近交系小鼠由本中心用ＡＭＭＳ／１与Ｃ３Ｈ／ＨｅＭｓ２种近交系小鼠杂交育成，现已繁殖至Ｆ４０多代。毛色为桂皮色，毛色基因为ＡＡｂｂＣＣＤＤ；经组织相容性基因、生化基因及染色体组型分析等遗传检测，符合近交系标准。其初孕期产仔数为６．５２±１．４３，离乳率为８８．８１％（１～６胎），成年雌鼠体重为（２２．８０±１．４７）ｇ，雄鼠为（２４．７７±１．６５）ｇ，经产母鼠乳腺癌发病率为５６．７％。血清ＩｇＧ含量随日龄而增加，相同条件下，雌性比雄性高。该系小鼠可作为莱姆螺旋体病的模型动物。     

SV40增强子在bGH转基因鼠体内对真核基因转录效率的影响

把ＳＶ４０的增强子序列以紧邻（ｐＳＶＣＡＴＬＢＧＨ）和相距２．３ｋｂ的距离克隆到小鼠金属巯基组氨酸三甲内盐基因（ＭＴ－Ｉ）启动子的上游，用以研究了在体内（ｉｎｖｉｖｏ）环境下原核基因的增强于对真核基因转录调控的影响，以及增强子与启动子的距离对增强于增强转录效率的影响。在建立了ｐＳＶＣＡＴＬＢＧＨ和ｐＳＶ２ＬＢＧＨ两种转基因结构的不同种系的转基因鼠后，通过分析ＩＣＲ、ＫＢ（昆明白）和Ｃ５７ＢＬ３种种系的ｐＳＶＣＡＴＬＢＧＨ转基因鼠的６种主要器官中的ＣＡＴ活性，证明ＳＶ４０增强子可以增强真核基因──ＣＡＴ基因的转录效率而无种属及组织特异性；通过比较ＩＣＲ和昆明白（ＫＢ）两种种系的ｐＳＶＣＡＴＬＢＧＨ和ｐＳＶ２ＬＢＧＨ转基因鼠的心脏和肝脏中ｂＧＨｍＲＮＡ水平，证明在转基因鼠体内，在２．３ｋｂ距离内，ＳＶ４０增强子对由ＭＴ－Ｉ启动子启动的真核基因──ｂＧＨ基因的转录效率的增强效果无明显差异。     

附植前小鼠胚胎上H-Y抗原表达的研究

用８～１２周龄ＢＡＬＢ／ｃ公鼠采取皮肤移植和脾细胞腹腔注射２种方式免疫同日龄纯系ＢＡＬＢ／ｃ母鼠,制备Ｈ－Ｙ抗血清。经精子微量细胞毒性试验,筛选的抗血清用于胚胎体外培养,以鉴定附植前小鼠胚胎上Ｈ－Ｙ抗原的表达。选用８ｃｅｌｌ－早期囊胚进行体外培养,分别于５～６、１８和２４ｈ观察胚胎发育情况。５～６ｈ后,Ｈ－Ｙ抗血清培养的胚胎退化率高达４０％,且发育迟缓,与自然性比例差异不明显（Ｐ〉０．０５）。正常     

一种快速有效制备单克隆抗体的方法

以人绒毛膜促性腺激素（ｈＣＧ）为抗原,对ＢＡＬＢ／ｃ小鼠一次脾内直接注射免疫,免疫后６ｄ,取其血清进行抗体检测,结果１２８００倍稀释度仍呈阳性。取此免疫小鼠脾细胞与同系小鼠骨髓瘤细胞ＮＳ－１进行细胞融合。融合后,将经检测抗体阳性的细胞孔置于显微镜下,挑选单个克隆进行克隆化,得到２株单克隆抗体细胞株２Ａ８、４Ｅ６。将其分别接种于ＢＡＬＢ／ｃ小鼠腹腔中,收获的腹水效价分别达１０－６和１０－５。     

AMMS／13近交系小鼠的培养及其生物学特性

ＡＭＭＳ／１３近交系小鼠由本中心用ＡＭＭＳ／１与Ｃ３Ｈ／ＨｅＭｓ２种近交系小鼠杂交育成，现已繁殖至Ｆ４０多代。毛色为桂皮色，毛色基因为ＡＡｂｂＣＣＤＤ；经组织相容性基因、生化基因及染色体组型分析等遗传检测，符全中近交系标准，其初孕期产仔数为６．５２±１．４３，离乳率为８８．８１％（１～６胎），成年雌鼠体重为（２２．８０±１．４７）ｇ，雄鼠为（２４．７７±１．６５）ｇ，经产母鼠乳腺癌发病率为５６．７     

Plasma concentrations of luteinising hormone and body weights during somatic maturation in intact and castrated Australorp cockerels from a line of hens selected for increased ovulation rate

1. Plasma concentrations of luteinising hormone (LH), comb size and body weight were measured between 46 and 208 d of age in intact and castrated cockerels from lines of selected and control Australorp domestic chickens. The selected line had been selected for increased rate of lay by reducing oviposition intervals within sequences. The cockerels were reared and maintained on 15.25 h light/d. 2. Concentrations of plasma LH in the intact control cockerels were low in the 'immature' phase (less than 100 d old) and increased during the 'mature' phase (older than 175 d) with a peak occurring when the testes are beginning to grow at the onset of the 'mature' phase. In comparison with the control line of cockerels, the selected line had significantly higher plasma LH concentrations at the onset of the 'mature' phase. Selection had no effect on the mean concentration of plasma LH in either the immature phase or a few weeks after the onset of the mature phase. 3. There was no effect of selection in sibling females for higher rates of lay on changes in comb size or body weight during sexual maturation in the intact cockerels. 4. Castration at 45-46 d of age resulted in increased plasma LH concentrations and no comb growth. Plasma LH concentration increased progressively between 40-208 d. There was no difference between the two lines of cockerels in plasma LH concentration or rate of body growth after castration. 5. It is concluded that selection of females for a change in the rate of egg production has resulted in increased plasma LH concentrations in sibling males around the onset of sexual maturation. Selection appears to have caused this effect by altering an unidentified component of the inhibitory feedback mechanism which controls the tonic secretion of LH.     

Endocrine studies in ivermectin-treated heifers from birth to puberty

Continuous treatment with ivermectin from birth to puberty advanced sexual maturation by 3.7 wk in Holstein heifers grazing pastures naturally infected with nematodes. Every 14 d jugular blood samples were taken from birth to 45 wk of age from all heifers. No differences in serum FSH, estradiol, or thyroxine levels were observed during the trial between the treated and untreated group. Mean LH levels were diminished in untreated heifers 4 wk before the first estrus and the amplitude of LH pulses was augmented in treated heifers when puberty was reached. Serum IGF-I levels increased from birth to 22 wk of age and then reached a plateau in both groups, but levels were consistently higher in treated heifers from 26 wk of age onward. Body weight gain was retarded in parasitized heifers and IGF-I values were positively correlated with body weight only during the first 20 wk of life. We suggest that enhanced prepubertal IGF-I levels in conjunction with increased prepubertal LH levels and pubertal LH pulse amplitude might be involved in the accelerated somatic maturation and in puberty advancement observed in ivermectin-treated heifers.     

Influence of prenatal testosterone treatment on foetal and prepubertal LHbeta-subunit mRNA and plasma LH concentrations in the female pig

The aim of this study was to investigate the potential role of foetal androgens in determining the sexual dimorphism in LH gene expression. Starting on day 30 p.c. pregnant sows were treated i.m. with testosterone propionate (TP) three times at 2-day intervals (TP30 treatment) or received additional TP treatment starting on day 40 p.c. (TP30/40). Sows were allowed to farrow and after frequent blood samples for LH determination were collected prepubertally (6 months) from the female offspring anterior pituitary LHbeta subunit mRNA levels were determined. In Experiment 2 pregnant sows were treated as TP30 before or received similar treatment starting on day 40 p.c. (TP40), but anterior pituitary LHbeta mRNA and plasma LH concentrations were determined at day 80 p.c. TP30 or TP30/40 treatment did not affect mean plasma LH concentrations nor LHbeta mRNA levels at 6 months of age but caused marked masculinization of external genitalia. At day 80 p.c. LHbeta mRNA and plasma LH levels were higher in female than in male foetuses. TP40 treatment suppressed LHbeta mRNA and plasma LH levels while TP30 treatment had no effect on LHbeta mRNA levels but caused masculinization of external genitalia in contrast to TP40. Our findings support the notion that the peak in plasma testosterone observed by others in the male pig foetus 5 weeks p.c. not only determines sexual differentiation of the LH surge mechanism but also LH gene expression in the foetus. The critical period for this process seems to succeed phenotypic differentiation (which appears to be largely completed before day 40 p.c.). The tonic mode of prepubertal LH gene expression and LH secretion in female pigs is not affected greatly by testosterone treatment at the stages of development that were investigated.     

Plasma concentrations of luteinising hormone, follicle stimulating hormone, androgen, growth hormone, prolactin, thyroxine and triiodothyronine during growth and sexual development in the cockerel

Changes in concentrations of plasma luteinising hormone (LH), follicle stimulating hormone (FSH), androgen, growth hormone (GH), prolactin (Prl), thyroxine (T4) and triiodothyronine (T3) were measured during growth and sexual maturation in broiler cockerels reared in continuous light to 7 weeks and 14 h light/d thereafter. Concentrations of LH and FSH began to increase between 13 and 15 weeks, while those of androgens increased between 16 and 17 weeks. FSH concentration increased faster than that of LH. Concentrations of GH and Prl were high at 3 weeks; that of GH decreasing progressively between 3 and 14 weeks of age and thereafter remaining low, while that of Prl was low between 5 and 9 weeks, relatively high between 10 and 13 weeks, and then temporarily decreasing before increasing progressively during sexual maturation. Concentrations of T3 and T4 were higher in juvenile than in adult birds.     

湖羊和考力代羊公羔垂体－性腺轴系内分泌活动的差异

用放射免疫方法测定了湖羊和考力代羊公羔从初生到１８０日龄垂体内ＬＨ总量，血浆ＬＨ和睾酮浓度的变化。结果表明：湖羊从初生到９０日龄垂体内ＬＨ总量迅速上升（Ｐ＜０．０１），以后呈下降趋势；血浆ＬＨ浓度０～２０日龄较低（０．８９～１．０３ｍＩｕ／ｍｌ），３０日龄开始上升，９０日龄达到峰值（２．３４ｍＩＵ／ｍｌ），以后呈下降趋势。血浆睾酮从４０日龄起迅速上升，１２０日龄达到２．７３ｎｇ／ｍｌ，以后维持于高水平（２．３４～４．４４ｎｇ／ｍｌ）。考力代羊０～１８０日龄垂体内ＬＨ总量呈持续上升趋势（Ｐ＜０．０１），血浆ＬＨ水平０～８０日龄维持较低水平（０．５２±０．９９ｍＩｕ／ｍｌ），以后呈上升趋势；血浆睾酮水平０～１３０日龄很低（０．１９～１．１３ｎｇ／ｍｌ），１４０日龄开始上升。两品种比较，０～９０日龄湖羊垂体内的ＬＨ总量，血浆ＬＨ及睾酮水平均高于考力代羊。提示湖羊公羔性成熟早与其生后早期垂体合成和释放ＬＨ水平高有关。     

Normal sexual maturation and reproductive function in domestic hens following unilateral adrenalectomy

The ovulation-inducing properties of adrenal hormones and the anatomical juxtaposition of the left adrenal gland and the ovary suggest that a functional relationship exists between these two endocrine organs. To test this hypothesis, the effect of unilateral adrenalectomy on sexual maturation and reproductive function was examined in left and right adrenalectomized SCWL pullets. Between 9 and 13 weeks of age, 24 and 12 pullets were either left or right adrenalectomized, respectively; 12 birds were sham operated and 7 birds served as unoperated controls. Blood samples were obtained immediately before and after surgery, 48h after surgery and at 14, 19 and 23 weeks of age. All samples were analyzed for plasma corticosterone by radioimmunoassay. At 20 weeks of age all birds were weighed and the photoschedule was changed from 8L:16D to 16L:8D. During the first 52 days following photostimulation the age at first egg and the distribution of ovipositions within the 24h photoschedule were recorded.Mean plasma corticosterone levels of the unilaterally adrenalectomized hens were not significantly different (P > .05) from those of control birds 48h after surgery or at 14, 19 and 23 weeks of age. Unilateral adrenalectomy had no effect on body weight at 20 weeks, average age at first egg, or percent hen-day production. In addition, 95% of the eggs laid in the first 52 days after photostimulation were restricted to a 10 hour period of the day regardless of the surgical treatment. These observations indicate that the removal of either the left or the right adrenal gland does not affect plasma levels of corticosterone, sexual maturation, or the open period for LH release as evidenced by the times of oviposition and fail to support the hypothesis of a localized functional relationship between the left adrenal gland and the ovary.     

A pregnant mouse model for bovine Tritrichomonas foetus infection

The economically important effects of Tritrichomonas foetus infection in cattle are abortion and infertility, yet there has not been an animal model to examine the parasite-host interactions during gestation. In this study, 5- and 7- to 8-week-old BALB/cAnNCr, BALB/cJ, and SCID/NCr mice on a BALB/c background were intravaginally infected with T. foetus. All BALB/cAnNCr and BALB/cJ mice, and 89% of SCID/NCr mice sustained infections for 13 weeks, if inoculated before 5 weeks of age. Infection rates were lower in all mouse strains inoculated at 7 weeks of age, although BALB/cAnNCr mice were significantly more susceptible than BALB/cJ or SCID/NCr mice. Vaginal bacterial flora did not account for the variation in mouse-strain susceptibility, although coagulase-negative staphylococci in vaginal flora were associated with failure of T. foetus to infect. As with infected cattle, T. foetus-specific vaginal immunoglobulin (Ig) G and IgA antibodies were elevated after infection. The number and viability of day-10 fetuses were reduced in mice infected at 5 weeks of age and bred 12 weeks after infection. Lesions in pregnant and nonpregnant infected mice, including suppurative and eosinophilic vaginitis; cervicitis; endometritis with distension of the uterine lumen; endometrial ulceration; and glandular ectasia, with neutrophils in the glandular lumen and loss of gland epithelium, were similar to those in cattle. The decidua and placenta were multifocally necrotic. Immunohistochemistry demonstrated trichomonads in vaginal folds and uterine glands, and adjacent to fetal tissues. In summary, experimentally infected BALB/cAnNCr mice showed many pathologic similarities to cattle and may serve as a model to study host-trichomonad interactions.     

Changes in luteinizing hormone secretion after estradiol treatment in prepubertal Nelore heifers

Changes in luteinizing hormone (LH) secretion after 17β-estradiol (E(2)) injection were evaluated during sexual maturation in 10 prepubertal Nelore heifers. Heifers were divided into 2 groups: intact (I) and ovariectomized (OVX). 17β-estradiol (2 μg/kg) was administered to both groups at 10, 13, and 17 mo of age. Only at 10 mo of age was there a greater mean LH concentration in OVX heifers (1.33 ± 0.29 ng/mL) compared with the I group (0.57 ± 0.15 ng/mL). At 13 and 17 mo of age there was no significant difference between the 2 groups in any of the evaluated variables (number of peaks, total peak area, greatest peak area, and time to greatest peak occurrence). This suggests a decrease in negative E(2) feedback associated with an increase in positive feedback to LH secretion during sexual maturation, and these were likely the key factors that determined the time of first ovulation in Nelore heifers.     

Luteinizing hormone during sexual maturation in pony mares

Luteinizing hormone (LH) was quantified in pony mares during artificially induced sexual maturation. Ovarian follicular development was also assessed by rectal palpation of the ovaries. With the exception of large periovulatory LH concentrations in two mares that ovulated, LH concentrations were not significantly different in mares undergoing sexual maturation and thus having marked follicular development when compared with mares that were not undergoing sexual maturation and thus did not have marked follicular development. These results indicate a dissociation in time between the onset of follicular development and the increase in LH which is associated with the first ovulation of the year.     

Effect of bovine growth hormone gene expression, sex and age on plasma gonadotropins, estrone and testosterone in prepuberal pigs.

Chronic supraphysiological blood levels of growth hormone (GH) may retard sexual maturation in swine. Pigs used in this study included four founder transgenic pigs (two gilts and two boars) expressing a mouse transferrin (TF) promoter fused to a bovine (b) GH structural gene, 13 second- or third- generation transgenic pigs (seven gilts and six boars) expressing a mouse metallothionein (MT) promoter fused to a bGH structural gene and 16 control littermates (eight gilts and eight boars). Blood plasma levels of LH, FSH, estrone and testosterone were measured to determine whether expression of bGH genes altered secretion of hormones between 80 and 180 days of age. Presence of a bGH gene was detected by hybridization of DNA in dot blots of tail biopsies. Expression of a bGH gene was detected by radioimmunoassay of plasma bGH. In four TFbGH founder transgenic pigs bGH ranged from 164 to 1948 ng/ml; in one MTbGH transgenic boar of line 3104 bGH was 1211 ng/ml; and in 12 pigs of line 3706 bGH ranged from 25 to 190 ng/ml. Expression of bGH in transgenic pigs lowered (P = .0192) plasma LH with no significant differences between sexes, had no significant effect on plasma FSH and lowered plasma estrone (P = .0001) and testosterone (P = .0269) in boars (but not gilts). Plasma estrone and testosterone were higher (P = .0001) in boars than in gilts. Plasma FSH was higher (P = .0001) in gilts than boars and decreased (P = .0001) with advancing age in gilts but not in boars.(ABSTRACT TRUNCATED AT 250 WORDS)