社群压力对圈养雌性亚洲象动情的影响

亚洲象是中国一级濒危保护动物,改善圈养亚洲象的繁殖状况是亚洲象保护工作的重要内容之一。本研究旨在通过分析社群压力对圈养雌性亚洲象应激和动情状况的影响,从而探究圈养雌性亚洲象长期不动情的原因。通过放射性免疫法检测雌性亚洲象尿液中皮质醇、孕酮和雌二醇水平以及粪便中皮质醇和雌二醇水平,以雌激素水平反映亚洲象的动情状况,以皮质醇水平反映亚洲象的应激状态,以争斗行为和友好行为的发生情况反映圈养群体的社群压力。研究发现：(1)处于优势地位的个体表现出更多的斗争行为,处于从属地位的个体受到更多的攻击行为;(2)优势个体的皮质醇水平显著高于处于从属地位个体的皮质醇水平;(3)优势个体的雌二醇和孕酮具有小幅周期性波动,而从属个体的雌二醇和孕酮水平没有表现出明显的波动。从本研究结果可以看出圈养亚洲象群体中优势个体对从属个体的行为抑制可能是导致从属个体雌激素水平低,长期不能参与繁殖的原因。     

小熊猫繁殖周期血清雌二醇和孕酮含量变化

为研究小熊猫繁殖周期血清雌二醇、孕酮含量变化规律,采用化学发光免疫分析法连续16 次测定了2只成体雌性小熊猫血清雌二醇和孕酮含量变化,历经发情间期、发情期和两次妊娠期;连续9次测定了7只小熊猫妊娠期的孕酮含量变化。结果:(1)发情间期,小熊猫血清雌二醇的水平一直维持在低水平(基础水平),进入发情前期,血清雌二醇水平明显升高,在发情期一直维持高水平,配种后迅速降至基础水平; (2)小熊猫血清孕酮含量在发情间期和发情期均维持在较低水平,直至发情期过后才出现升高,在妊娠期一直维持高水平,峰值出现在5 月;(3)发情的小熊猫不论妊娠与否,在妊娠期内血清孕酮含量均维持在高水平。研究表明:小熊猫血清雌二醇、孕酮含量变化能直接反映其繁殖规律,雌二醇对启动雌性小熊猫季节性繁殖起重要作用;在妊娠期内小熊猫血清孕酮含量升高不能作为判断小熊猫妊娠的标准;雌性小熊猫在妊娠期有假孕现象。     

大熊猫生殖生物学研究:Ⅰ.大熊猫发情期血清和尿液中促黄体素、孕酮和17β-雌二醇含量的变化

作者用放射免疫法和生物测定法对4只大熊猫发情期血清和尿液中的促黄体素、孕酮和17β-雌二醇的含量进行分析。结果表明:3只大熊猫在发情高峰期均出现雌二醇和促黄体素高峰;LH峰值出现在E_2峰值之后。根据雌兽在发情期血清和尿液中这二种激素含量的变化可为选择人工授精的最佳时间提供可靠的理论依据。     

注射LHRHa对泥鳅血清性类固醇激素变化研究

研究了注射促黄体激素类似物(LHRHa)后,泥鳅(Misgurnus anguillicaudatus)血清性类同醇激素的变化规律,并探讨在泥鳅繁殖季节时.孕酮(P)、睾酮(T)和雌二醇(E2)对性腺发育的作用及调节机制.实验共分两组,对照组和实验组;对照组只注射生理盐水;实验组注射LHRHa,雌鱼0.2 μg/g,雄鱼减半.注射前尾静脉采血,作为血液样本分析基础水平(Oh),注射药物后分别在7、24、48、72和96h尾静脉采血.测定雌鱼睾酮、雌二醇和孕酮,雄鱼孕酮和睾酬血清浓度.实验结果表明:注射LHRHa,雌鱼血清睾酮和雌二醇浓度显著高于对照组,雄鱼血清睾酮和孕酮显著高于对照组(P<0.05);24h浓度较高.雌鱼孕酬、睾酮和雌二醇分别为(0.710±0.082)ng/mL、(9.00±0.57)ng/mL和(696.4±26.2)pg/mL,雄鱼孕酮和睾酮分别为(0.527±0.121)ng/mL和(9.62±0.62)ng/mL.实验组雌鱼孕酮变化基本规律为,基础水平(0-7h)-逐渐升至最高(7-24h)-逐渐降至基础水平(24-48h)-维持基础水平(48-96h).实验组雌鱼睾酮和雌二醇与雄鱼孕酮和睾酮变化规律基本相似,其规律为,逐渐上升至最高(0-24h)-逐渐降至基础水平(24-72h)-维持基础水(72-96h).24h对照组雌鱼睾酮和雌二醇显著升高,浓度分别为:睾酮(2.20±0.18)ng/mL,雌二醇(269.1±36.6)pg/mL.对照组雄鱼血清孕酮和睾酮浓度实验期间均无显著变化.研究认为:LHRHa能够刺激泥鳅性类同醇激素分泌,特别是睾酮的分泌,显著提高雌鱼性腺指数(GSI).但刺激P的分泌调控能力有限,实验期间处于较低水平,诱导排卵效果差,泥鳅的性类固醇激素可能有特殊的调节机制.雌二醇和睾酮对性腺成熟有重要作用,孕酮对介导卵细胞最终成熟和排卵可能起重要作用,而雌二醇和睾酮无明显效果.     

酪氨酸对大鼠子宫胞浆雌,孕激素受体的影响

采用放射受体分析法,测定了动情周期不同阶段及去卵巢大鼠子宫胞浆雌二醇和孕酮受体含量,并观察了子宫腔内注射酪、丝、苏三种氨基酸对子宫胞浆雌。醇、孕酮受体含量的影响。结果表明：（１）Ｌ－酪氨酸对动情前期、动情期、间情期大鼠子宫胞浆雌二醇和孕酮受体都具有明显的降低作用。（２）Ｌ－酪氨酸也降低去卵巢大鼠子宫胞浆雌二醇和孕酮含量,即这一作用不是通过影响卵巢激素分泌实现的。（３）Ｌ－苏氨酸仅可降低动情期和间情期大鼠子宫胞浆孕酮受体含量,而对相应周期雌二醇受体没有明显作用。（４）Ｌ－丝氨酸和Ｌ－苏氨酸对去卵巢大鼠子宫胞浆雌二醇和孕酮受体均无影响。     

笼养雌性黑叶猴尿中性腺激素水平变化与性行为、等级序位的关系

2003年10月30日至2004年11月21日,采集了3只笼养雌性黑叶猴妊娠期和1 只笼养雌性黑叶猴发情期的晨尿,并用放射免疫分析法检测尿液中孕酮和雌二醇浓度,同时用全事件观察法观察黑叶猴的行为,分析雌性黑叶猴的行为与其尿中的性腺激素的关系。研究结果发现:1)进入妊娠期,雌性黑叶猴尿中的雌二醇浓度逐渐上升,中后期达高峰;而尿中孕酮浓度在妊娠初期仍维持在放免法的灵敏度以下,妊娠约1 个月后才升高至灵敏度以上(13.39 ng/ mgCr);2)在妊娠中期,雌性黑叶猴仍维持着较高频率的邀配行为,但与雌激素的变化无明显的相关关;3)发情期,雌猴尿中的雌二醇浓度与其邀配行为呈正相关;4)雌性黑叶猴的性激素高低与其等级序位无关,但序位高的雌猴繁殖较早。     

笼养雌性果子狸同性数量对发情状态的影响及繁殖季节尿液雌激素浓度的变化

本研究试图揭示 (1)社会环境影响雌性果子狸 (Pagumalarvata)的交配日期 ,(2 )哺乳期母兽有雌二醇浓度升高的现象。通过检查是否排出交配栓并结合交配行为的发生与否确定开始交配的日期 ,使用放射免疫方法测定尿中雌二醇浓度。结果表明 (1)一雄两雌组中优势雌兽开始交配的日期显著早于劣势雌兽和单雌组雌兽 ,劣势雌兽和单雌组雌兽之间无差异 ;交配期优势雌兽尿液中雌二醇浓度明显高于劣势雌兽 ,而与单雌组中的雌兽无差异 ,但单雌组中雌兽尿液中雌二醇的浓度明显高于劣势雌兽雌二醇的浓度 ;(2 ) 5头母兽产后第二天雌二醇浓度开始上升 ,在第 5天时达到高峰 ,其中 4头母兽的雌二醇浓度共出现了两个峰值 ,其间隔为 16 75± 4 4 6 (4)天。上述结果说明 :(1)社会影响仅对优势雌性个体的繁殖有促进作用 ;(2 )哺乳期雌二醇水平的升高是季节性多次发情的基础。     

雌性川金丝猴的邀配行为与尿液雌二醇水平的关系

2001年10～12月及2002年9月～11月,我们对上海野生动物园一群半散养条件下的川金丝猴进行了研究,记录了群体内的4只成年雌猴的邀配行为,同时收集了观察对象的晨尿,利用放射免疫法测定其中的雌二醇含量。结果显示,在未受孕的月经周期内,雌猴的邀配行为集中在雌二醇高峰前后,雌猴在卵泡期和黄体期邀配频次显著下降,说明邀配行为受雌二醇水平的调控。同一群体内不同个体的月经周期并不同步,邀配高峰互不重叠,这可能是雌猴避免相互竞争产生的结果。利用雌二醇测定结果推断受孕日期,发现进入妊娠期后雌猴仍然频繁地向雄猴邀配,并得到雄猴的响应。妊娠期内的雌二醇水平虽有波动,但都高于月经周期内排卵前的雌二醇高峰,邀配频次与雌二醇水平没有明显的相关性,因此这一时期的邀配行为不能归结为激素作用的结果,它们应该具有其它社会功能[动物学报49(6)：736～741,2003]。     

大熊猫粪便样本处理与激素萃取方法比较

通过测定圈养动物粪便中的激素水平,监测其发情与怀孕状态和评估其福利状况是目前普遍采用的一种实验手段。然而,现有研究对于圈养野生动物粪便样本的处理及其激素萃取方法存在很大分歧,研究结果也不尽一致。本研究采集了10只(雌∶雄=1∶1)圈养大熊猫(Ailuropoda melanoleuca)的粪便样本,分别采用冷冻干燥-研筛法和冷冻干燥-粉碎法处理粪便样本,然后分别使用80%甲醇、90%乙醇和95%乙醇3种萃取剂进行激素萃取,最后比较2种粪便处理方法和3种溶剂萃取方法所获得的粪便样本中孕酮、雌二醇、睾酮和皮质醇的浓度。结果表明,冷冻干燥-研筛法结合80%甲醇溶液萃取处理的样本中雌二醇和孕酮检测值最高,冷冻干燥-粉碎法结合80%甲醇溶液萃取处理的样本中睾酮检测值最高。冷冻干燥-粉碎法结合90%乙醇溶液萃取处理的样本与冷冻干燥-研筛法结合80%甲醇溶液萃取处理的样本中皮质醇检测值更高,且2种方法的检测结果差异不显著。综合粪便处理难易程度和萃取溶剂性质,建议雌二醇、孕酮和睾酮激素检测根据最高检测浓度的方法进行粪便前处理,皮质醇激素检测使用冷冻干燥-粉碎法结合90%乙醇溶液萃取方法进行粪便前处理。...     

川金丝猴尿液类固醇激素的保存时效性

尿液类固醇激素检测已经广泛运用于野生动物的生理机能、健康状况和繁殖状态的研究,由于分析条件以及样品采集时间限制,一般尿液样品需保存一段时间后才能在实验室分析,不同物种尿液类固醇在不同保存条件的保存时效有差异。本研究利用2只成年雄性和4只成年雌性的尿液样品共21份,确定川金丝猴尿液类固醇的保存时效和保存方法。结果表明:4℃时,雄性川金丝猴尿液睾酮、雌性尿液睾酮、孕酮的保存时效为7 d左右;雌性尿液雌二醇的保存时效在3 d以内。-20℃时,雄性川金丝猴尿液中睾酮的含量在60 d内保持稳定;雌性尿液中睾酮、孕酮和雌二醇的含量在60 d、45 d、60 d内保持稳定。-20℃保存川金丝猴尿液样品是一种有效、可靠的方法。     

Secretory Pattern of Inhibin During Estrous Cycle and Pregnancy in African (Loxodonta africana) and Asian (Elephas maximus) Elephants

The ovary of female elephants has multiple corpora lutea (CL) during the estrous cycle and gestation. The previous reports clearly demonstrated that inhibin was secreted from lutein cells as well as granulosa cells of antral follicles in cyclic Asian elephants. The aim of this study is to investigate the inhibin secretion during the pregnancy in African and Asian elephants. Two African elephants and two Asian elephants were subjected to this study. Circulating levels of immunoreactive (ir‐) inhibin and progesterone were measured by radioimmunoassay. Four pregnant periods of an African elephant and three pregnant periods of an Asian elephant were analyzed in this study. Circulating levels of ir‐inhibin started to increase at 1 or 2 week before the ovulation and reached the peak level 3 or 4 weeks earlier than progesterone during the estrous cycle in both African and Asian elephants. After last luteal phase, the serum levels of ir‐inhibin remained low throughout pregnancy in both an African and an Asian elephant. The mean levels of ir‐inhibin during the pregnancy were lower than the luteal phase in the estrous cycle despite high progesterone levels were maintained throughout the pregnancy. These results strongly suggest that CL secrete a large amount of progesterone but not inhibin during the pregnancy in elephants. Zoo Biol 31:511‐522, 2012. © 2011 Wiley Periodicals, Inc.     

Reproductive and hormonal changes during the estrous cycle and pregnancy in Asian elephants (Elephas maximus)

Serum progesterone and urinary total estrogen concentrations were determined weekly to bi-weekly in 2 female Asian elephants for 96 weeks. The mean estrous interval was approximately 16 weeks in the nonpregnant animal. A total of 5 cycles were observed in the 96 week study period. The serum progesterone concentration ranged from 150 pg/ml to greater than 350 pg/ml during the luteal phase of the estrous cycle. The serum progesterone was elevated for 8–12 week weeks of the 16 week estrous cycle. The urinary total estrogen concentration ranged from less than 10 to greater than 300 pg/μg creatinine. The second animal was pregnant at the beginning of the study period. The serum progesterone concentration was elevated (> 100 pg/ml) in the pregnant animal until parturition. The urinary total estrogens increased from approximately 50 pg/μg creatinine to greater than 400 pg/μg creatinine during the first year of pregnancy and remained elevated until parturition. Estrous cycling had not resumed by 3 months post partum.     

LHRH - Induced ovulation and fertility of anestrous goats

Seventeen female mature anestrous does were used to study the effect of luteinizing hormone-releasing hormone (LHRH) on ovulation (Experiment I) and on fertility rate and blood estrogen/progesterone concentrations (Experiment II). Laparotomy after day 8 of treatment with a single injection of LHRH (300 ug) and estradiol cypionate (0.2 mg/kg) revealed evidence of ovulation in two out of three and a developed follicle in the third. Similar treatment to six does in Experiment II, when followed by natural mating with a fertile buck, produced pregnancy in two does, pseudopregnancy in two and no effect (nonpregnancy) in the remaining two animals. The pregnant does had normal parturition after 148 to 150 days of gestation. In pregnant does, blood progesterone levels first showed a gradual increase until day 130 (10.07 ng/ml) and then declined sharply at 48 hours before parturition. Estrogen concentration, on the other hand, failed to increase until day 80, and thereafter it reached a peak (1800 pg/ml) at 24 hours prior to parturition; the level declined sharply at 24 hours after parturition. In pseudopregnant does, progesterone levels remained in close proximity with those of pregnant does until day 90, when they started to decline.     

Quantitation of deoxycorticosterone and its relationship to progesterone in the prepartum bovine.

A method and its validation is described for the radioimmunological measurement of deoxycorticosterone (DOC) in bovine serum. Levels of DOC and progesterone were determined in six pregnant heifers from one to three weeks before and during parturition. Levels of these steroids fluctuated widely from day to day and tended to be inversely related (r = -0.24). High levels of DOC in conjunction with low levels of progesterone at or near parturition are suggestive that DOC is involved in the parturition process.     

Peripheral plasma levels of progesterone in pregnant goats and in pregnant goats treated with prostaglandin F2a

Prostaglandin or prostaglandin analogues have been shown to be luteolytic in the pregnant goat. In this study the temporal changes in the plasma concentrations of progesterone during pregnancy and after administration of PGF2a to pregnant goats are described. PGF2a administration to pregnant goats at 30 and 65 days after breeding induced abortion within 34 to 75 hours. These abortions were accompanied by estrus and profuse muco-hemorrhagic discharges. When PGF2a was administered to pregnant goats 140 or 142 days after breeding, premature parturition occurred within 42 to 76 hours. Live kids were delivered in all cases. The plasma levels of progesterone in all pregnant goats showed dramatic decreases within 24 hours after the prostaglandin injections and continued to decrease gradually until abortions or premature parturition. Thereafter, the progesterone levels remained low for several days.     

Progesterone concentrations and contents in the plasma, ovary, adrenal gland and placenta of the pregnant Natal clinging bat Miniopterus schreibersii natalensis

Reproduction in the Natal clinging bat in South Africa at 25°S is characterized by fertilization in April, implantation during July and parturition in November. In the present study plasma progesterone concentrations peaked two months before implantation, this coinciding with significant peaks in ovarian progesterone content and concentration. Plasma progesterone concentrations remained relatively low during and after implantation, but increased significantly during the limb bud stage to peak levels one month before parturition. Adrenal progesterone content and concentration did not follow a specific trend; post-implantation ovarian progesterone content and concentration remained at baseline values. Placental progesterone content increased significantly with foetal weight (age). The present study showed that pregnancy in these bats is characterized by two major sources of progesterone, with the ovary as the primary source before implantation and the placenta the primary source during embryonic and foetal development.     

Effect on pregnancy and plasma progesterone of exogenous steroid maintenance in ovariectomised pregnant rabbits

Pregnancy was maintained in ovariectomised does with 1 to 4 mg/day of exogenous progesterone with or without 0.2 μg/day of estradiol. Progesterone doses were designed to give similar plasma progesterone levels in treated groups to those found in normal pregnancy, and were measured and compared with normals since this comparison does not appear to have been published previously. In normal pregnancy mean progesterone levels reached 10 ng/ml on day 7 and then plateaued at 14 ng/ml between day 10 and 20 before falling to very low levels at parturition. In treated groups progesterone levels reached 10 ng/ml on day 6 and remained between 10 and 13 ng/ml until day 20 before declining. The difference between treated and control plasma progesterone plateau levels was tested using the t-test and was found not to be significant. The differences in progesterone levels between treated groups with or without estradiol, whether pregnant or not, were also not significant. Mean litter sizes (alive or dead) were not significantly different. However, fetal viability in the group maintained on progesterone alone was significantly lower than in the normal controls.     

Maintenance of pregnancy and levels of progesterone and relaxin in the serum of gilts following a stepwise reduction in the number of corpora lutea

The number of corpora lutea (CL) was reduced in pregnant gilts in a stepwise fashion. Eleven pregnant gilts were unilaterally ovariectomized at Day 30, leaving from 6 to 12 CL on the remaining ovary. At Day 40, the number of CL was again reduced by about half in each gilt and this was repeated on Day 50 until 1 to 3 CL remained. Blood was obtained to determine the level of progesterone in plasma on each day of surgery and 24 h later. Four gilts aborted; one had 1 CL and three had 2 CL. One gilt which had 1 CL resorbed the litter. The six gilts that maintained pregnancy from Day 50 to parturition had 1, 3, 2, 2, 2 and 2 CL, respectively. Gilts pregnant at Day 60 were also bled on that day and at 8-h intervals beginning 2 to 3 days prior to expected parturition at Day 114. At laparotomy on Day 50, gilts had from 3 to 20, nonluteinized follicles ranging from 12 to 20 mm in diameter. Hypertrophy of CL was not detected, nor were accessory CL formed. The level of progesterone in serum dropped significantly 24 h after surgery and rose to levels intermediate to pre- and postsurgery levels 10 days later. Parturition was uneventful and levels of relaxin and progesterone appeared normal.     

Grooming Circadian Rhythmicity, Progesterone Levels and Partner Preference of the Reproductive Pair of a Captive Common Marmoset (Callithrix jacchus) Family Group during Pregnancy and after Parturition

One family group of common marmosets (Callithrix jacchus) maintained in captivity under natural environmental conditions (Natal, Brazil, 05°46'S, 35°12'W) was observed by focal sampling at two non-consecutive days per week during two non-consecutive pregnancies (pregnancy 1: the last 8 fortnights before parturition; pregnancy 2: the last 5 ones) and after parturition (4 fortnights for both). The hourly percentiles of the duration of self-grooming and allogrooming interactions of the reproductive pair were submitted to Cosinor analysis for the 24-h period (p ≤ 0.05). The reproductive female's progesterone was monitored by fecal collection twice a week between 7:00 h to 9:00 h. Levels of progesterone were determined by ELISA method. During pregnancy 1, all interactions of the reproductive pair showed a 24-h statistically significant period. However, after parturition this periodicity is not present in some behaviors of the reproductive male. This animal presents the 24-h periodicity only toward to the reproductive female, the subadult son and to the newborns. Hormonal levels of the reproductive female showed isolated increases above 100 ng/g at the second and third fortnight after parturition, but did not characterize ovulation. Between pregnancy 1 and 2, the family was increased by the birth of four animals. During pregnancy 2, a statistically significant 24-h period was find only in self-grooming of the reproductive male and female, and in the interactions between the reproductive pair. Also, in the interactions of the reproductive male with only one of the juvenile son. After parturition the reproductive female ovulated at the second fortnight and became pregnant again. At this time, those interactions still have a 24-h period, except in grooming directed to the juvenile son by the reproductive male. As in the first post-partum, grooming directed to the newborns showed statistically significant 24-h period. These results suggest that the reproductive pair performs 24-h rhythmic grooming interactions only with some animals, supposed to be the preferential grooming partners. Furthermore, the temporal grooming expression in common marmosets may be affected by the reproductive condition (progesterone levels) of the reproductive female, by the care of newborn after parturition and the group size.