Antifertility effects of quinestrol in male lesser bandicoot rat, Bandicota bengalensis, and potential in managing rodent population under field conditions

Integrating fertility control techniques using steroid hormones after lethal control can help reduce post control rebuildup of rodent populations.The current study is thefirst to assess the antifertility effects of quinestrol in male lesser bandicoot rat,Bandicota bengalensis which is the predominant rodent pest species in Southeast Asia.Rats in different groups were fed bait containing 0.00%,0.01%,0.02%,and 0.03%quinestrol for 10 days in laboratory and evaluated immediately,and 15,30,and 60 days after treatment discontinuation for effect on reproduction and other antifertility parameters.Effect of 0.03%quinestrol treatment for 15 days was also observed in managing rodent populations in groundnut cropfields.Treatment resulted in average consumption of 19.53±1.80,67.63±5.50,and 246.67±1.78 mg/kg bwt active ingredient by three treated groups of rats,respectively.No reproduction was observed in female rats mated with male rats treated with 0.03%quinestrol,even 30 days after cessation of treatment.Post-mortem examination showed a significant(P<0.0001)effect of treatment on organ weights(testis,cauda epididymis,seminal vesicles,and prostate gland)and different sperm parameters(sperm motility,sperm viability,sperm count,and sperm abnormality)in the cauda epididymalfluid with partial reversibility after 60 days.A significant(P<0.0001)effect of quinestrol on the histomorphology of testis and cauda epididymis was observed,suggesting its effect on spermatogenesis.Affected cell association and cell count in seminiferous tubules did not fully recover within 60 days of stopping treatment.Evaluation of the effects of quinestrol treatment in groundnutfields showed greater reductions in rodent activity infields treated with 2%zinc phosphide followed by 0.03%quinestrol treatment as compared tofields treated with 2%zinc phosphide alone.Research concludes that quinestrol has the potential to reduce fecundity and post control rebuildup of B.bengalensis populations,but long-term studies of the effectiveness of quinestrol under large-scalefield conditions are needed to use it as part of an integrated pest control program for rodents.

Antifertility effects of EP-1 (quinestrol and levonorgestrel) on Pacific rats (Rattus exulans)

Pest rodents pose a serious threat to island biodiversity.Fertility control could be an alternative approach to control the impact of rodents on these islands.In this study,we examined the antifertility effects of EP-1 baits containing quinestrol(E)and levonorgestrel(P)using a dose of 50 ppm E and P at three different ratios(E:P ratio=1:2,1:1,and 2:1)on Pacific rats(Rattus exulans)in the Xisha Islands,Hainan,China.Compared to the control group,all animals in EP-1 treatment groups showed significantly decreased food intake and body weight.In treated males,there were obvious abnormalities in testis structure and a significant decrease of relative seminal vesicle weight,but no significant effect on relative uterine and ovarian weights(g kg-1 body weight),or ovarian structure in females.Adding 8%sucrose to the original 50-ppm baits(E:P ratio=1:1)significantly increased bait palatability for males and females.This dose induced uterine edema and abnormalities of ovarian structure in females but had no significant negative effect on the relative testis,epididymis,and seminal vesicle weights(g kg-1 body weight)or sperm density in males.In summary,50-ppm EP-1(1:1)baits have the potential to disrupt the fertility of females,and 8%sucrose addition to the EP-1 baits(E:P ratio=1:1)could improve bait palatability.This dose disrupted the testis structure in males.Future studies are needed to improve bait acceptance and assess the antifertility effects of EP-1(1:1)on Pacific rats in captive breeding trials and underfield conditions.

Anti-fertility effect of levonorgestrel and quinestrol in Brandt’s voles(Lasiopodomys brandtii)

The combination of levonorgestrel and quinestrol(EP-1)has been shown to have anti-fertility effects on several wild rodents,but the mechanism underlying these effects is poorly understood.We investigated the effects of EP-1 and each of its components,levonorgestrel(P)and quinestrol(E),on the fertility of Brandt’s voles(Lasiopodomys brandtii)by using a gastric gavage method.The doses for EP-1,E and P were 1,0.34 and 0.66 mg/kg body weight,respectively.Male voles(n=98)were treated daily for 5 or 14 days,then the testes and epididymides were collected,weighed and examined histologically at 30(D30),60(D60)or 90(D90)days after the end of treatment.Four males were allowed to mate with normal females at D90.Female voles(n=75)were treated for 3 days and a further 3 days after a 7-day interval.The uteri and ovaries were weighed and examined histologically at 15(D15),30(D30)or 75(D75)days after the end of treatment.Each of three females were mated with fertile males at D30 and D75,respectively.Our results indicated that quinestrol(E)significantly decreased the sperm numbers in the testes as well as the weight of the testes and epididymides,with both of these tissues showing obvious structural abnormalities,and significantly reduced the litter size and the pup weight for females mated with males of the E treatment group.For female voles,treatment with E,P or EP-1 resulted in no marked influence on the fertility status.These data indicate that quinestrol(E)alone has a significant anti-fertility effect on male Brandt’s voles,but is ineffective in combination with levonorgestrel(P).

Fertility control of Rattus nitidus using quinestrol:effects on reproductive organs and social behavior

Fertility control has been identified by studies in the laboratory and the field as a more appropriate and long-term control strategy for rodent pests than lethal control.In this study,we investigated the effects of quinestrol on mass of reproductive organs and on social behaviors in female and male Himalayan field rats(Rattus nitidus).A total of 16 adult females and 16 adult males were randomly assigned to 4 groups.One male and one female group were fed rice with 0.005%quinestrol by weight for 7 days,and another 2 groups were fed rice only.After 7 days,rats were assigned to 10 min dyadic encounters between groups,and investigation,aggression,defense and attack latency were quantified.All animals were killed on day 10,and reproductive organs were dissected and weighed.Dyadic encounter data showed that there were obvious changes in social behaviors of quinestrol-treated rats.Quinestrol significantly inhibited the investigative behavior of quinestrol-treated males toward control females in Rattus nitidus,but seldom affected investigation between control males and quinestrol-treated females.Aggression of control females toward quinestrol-treated males was higher than that of quinestrol-treated females,and defense of quinestrol-treated males toward control females was more remarkable than that of control males.Quinestrol remarkably decreased wet masses of epididymis and spermotophore in males and ovaries in females,but had no effect on wet masses of testes and uteri after quinestrol treatment.These results indicate that the anti-fertility effects of quinestrol on R.nitidus are attributed to not only suppressing reproductive organs but also impacting social behaviors associated with territory defense and mate choice.

Recovery of fertility in quinestrol-treated or diethylstilbestroltreated mice:Implications for rodent management

Fertility control is an alternative strategy to traditional culling for the management of rodent pests.Previous studies have demonstrated that quinestrol is a potential contraceptive for male rodents,but the recovery of fertility in quinestrol-treated rodents has not been evaluated.This study used C57BL/6J mice to evaluate the recovery rate of male fertility after the administration of quinestrol.Diethylstilbestrol(DES),a non-steroid estrogenic compound,was used for comparison.Different groups of mice were treated with 1 mg/kg quinestrol,1 mg/kg DES,or castor oil separately for 7 days.These mice were then killed on days 8,22 and 50 respectively.Our results indicated that the weight of epididymides and seminal vesicles decreased significantly on days 8 and 22 in quinestrol/DES-treated mice,with extensive histological changes in the seminiferous tubules.Sperm concentrations in the cauda epididymal fluid were significantly reduced on days 8 and 22 in both quinestrol and DES treatment groups and on day 50 for the DES,but not the quinestrol group.Further analysis revealed that DES-treated mice exhibited a higher proportion of abnormal sperm accumulation in the epididymis,indicating that the normal sperm transportation to the cauda epididymis was blocked.Our results indicate that the anti-fertility effects on male mice given quinestrol were of shorter duration than for those receiving DES at the dose of 1 mg/kg body weight.

Antifertility effects of levonorgestrel,quinestrol,and their mixture(EP-1)on plateau zokor in the Qinghai–Tibetan Plateau

The plateau zokor(Eospalax baileyi)is a key species in the Qinghai-Tibetan Plateau ecosystem,and fertility control could be an ideal approach to manage populations of this subterranean species.In this laboratory study,we explored the effects of the mixture of levonorgestrel and quinestrol(EP-1,1:2),quinestrol(E),and levonorgestrel(P)on the reproductive status of plateau zokors.Groups of 5 animals of each sex were treated with different concentrations of EP-1(1,5,and 10 mg/kg),E(0.33,3.3,and 6.6 mg/kg),and P(0.67,3.35,and 6.7 mg/kg)by oral gavage over 7 successive days and killed on day 15.Body mass reduction was observed in the EP-1 and E groups.EP-1 and E significantly reduced the weight of testis and epididymis at 10 and 3.3 mg/kg,respectively.Sperm count and motility were significantly reduced by 5 mg/kg EP-1 and 0.33 mg/kg E.The levels of serum testosterone,estradiol,luteinizing hormone,and follicle stimulating hormone were significantly reduced by 5 mg/kg EP-1 and 3.3 mg/kg E.EP-1 and E significantly increased the uterine and ovarian weights at 10 and 3.3 mg/kg,respectively.In the plateau zokors,treatment with P had no influence on the reproductive status.These data demonstrate that EP-1 and E have an inhibitory effect on a range of reproductive parameters in the plateau zokors.Further assessment is required to determine the effects on breeding and recruitment in enclosure orfield experiments.

Anti-fertility effect of levonorgestrel and/or quinestrol on striped field mouse(Apodemus agrarius):evidence from both laboratory and field experiments

The effect of combined levonorgestrel(P)and quinestrol(E)on the fertility of stripedfield mouse(Apodemus agrarius)has not been evaluated.We performed a series of experiments in both the laboratory andfield to assess the effect of P and/or E on the fertility of A.agrarius.In the laboratory,to test the time-dependent anti-fertility ef-fects of P and E,as well as their mixtures,90 male stripedfield mice were randomly assigned to 6 treatment groups(n=60),and a control group(n=30).Mice in 3 treatment groups were administered 1 of the 3 compounds(1 mg�kg–1[body weight]EP-1,0.34 mg�kg–1 E,0.66 mg�kg–1 P)for 3 successive days(another half for 7 suc-cessive days)via oral gavage;mice were then sacrificed 15 and 45 days after initiating the gavage treatment.Ourfindings indicated that E and EP-1 treatment,but not P or control treatment,significantly decreased the sperm count in the caudal epididymis,as well as the weight of the testes,epididymides,and seminal vesicles.Additionally,fer-tile female mice mated with E-and EP-1-treated males produced smaller pups.These data indicate that E and EP-1 can induce infertility in male A.agrarius.In thefield,the population density of A.agrarius was significantly influ-enced by EP-1,and the rodent density in the treatment group was lower than that in the control group.Overall,our results indicate that EP-1 is an effective contraceptive in A.agrarius,a dominant rodent species in the farmland.

Assessment of non-target toxicity effects of synthetic estradiol, quinestrol, in chickens

Fertility control agents for the management of rodent populations are developing and maturing.Investigating the impacts on non-target species of consumption of these agents is essential.The present study assessed the non-target toxicity effects of quinestrol,a synthetic estrogen-based antifertility agent for managing rodent populations.Various quinestrol doses administered to male and female(n=60 each)chickens through single oral gavage were 0(A),10(B),50(C),and 150(D)mg/kg body weight.Chickens were assessed for effect on body weight,weight of vital and reproductive organs,reproductive hormones,histology of reproductive organs and egg laying rates after 15,30,and 135 days of treatment.Quinestrol did not induce mortality in chickens and its effects were time and dose dependent.The 90%egg-laying rates were delayed by 30,60 for groups B and C compared with the control group,and group D did not reach the 90%egg-laying rate by 135 days.Reproductive organs in males and females returned to normal levels within 30 and 135 days,respectively.With the exception of the FSH concentration in group D,reproductive hormones of both sexes were similar to controls by 30 days.No other significant effects were found.The present research demonstrated the safety of quinestrol on non-target species and facilitates recommendations for the general administration of quinestrol for rodent pest management.

二甲基亚砜对提高炔雌醚药物吸收和改善其适口性的作用

为提高炔雌醚药物在饵料中的利用率以及改善炔雌醚药饵对鼠类的适口性,筛选高效、安全的农药助剂,并优化饵料配制方法。以黄毛鼠为研究对象,采用单只饲喂法,测定了溶剂二甲基亚砜(DMSO)对炔雌醚药饵适口性的影响,高效液相色谱法检测不同配制的药饵中炔雌醚的分布浓度。结果显示,DMSO-炔雌醚药饵的糙米中炔雌醚的含量为炔雌醚药饵糙米中的1.5倍;DMSO可增加炔雌醚的渗透力。此外,雌雄黄毛鼠取食DMSO-炔雌醚药饵量显著低于空白饵料,而对炔雌醚药饵的取食量随时间延长逐渐降低,雄鼠第3次取食炔雌醚药饵量较空白饵料减少37.3%;雌性黄毛鼠初次取食DMSO-炔雌醚药饵量仅为对炔雌醚药饵取食量的24.1%;且雌鼠对空白饵料的消化率显著高于DMSO-炔雌醚药饵24.6%;DMSO-炔雌醚药饵组鼠体重下降显著。本研究明确了DMSO可以达到快速高效的溶解炔雌醚,且增强其在糙米中的渗透力,可实现农药化肥减量增效的需求,有望开发为具有良好应用前景的不育剂配方。

N,N-二甲基甲酰胺对炔雌醚不育作用和适口性的影响

【目的】明确添加高效、安全的助剂N,N-二甲基甲酰胺(N,N-Dimethylformamide,DMF)对提高不育剂炔雌醚(Quinestrol)药饵的不育效果,以及改善炔雌醚药饵对鼠类适口性的作用。【方法】试验设3个处理组,分别投喂三组小鼠空白饵料(C组)、炔雌醚药饵(T1组)和DMF-炔雌醚药饵(T2组),计算饵料消耗量。将3个处理组的雄、雌鼠合笼7 d,记录雌鼠怀孕及产仔情况。高效液相色谱法检测不同配制的药饵中炔雌醚的分布浓度。【结果】T1和T2组对雄、雌鼠体重均有显著影响,且T1和T2组雄鼠肾脏器官鲜重分别低于C组16.4%和19.7%。炔雌醚对雌性小鼠繁殖抑制作用明显,T1和T2组雌鼠产仔率降低至C组的37.5%和25.0%,产仔数仅为C组的35.0%和11.1%。DMF对炔雌醚药饵适口性改善作用不明显,高效液相色谱法检测药饵中药物的分布浓度结果表明,T2组的糙米中炔雌醚的含量为T1组的1.5倍;DMF提高了炔雌醚在糙米中的渗透,从而增加了小鼠的药物摄入量。【结论】DMF可快速有效溶解炔雌醚,并增强其在糙米中的渗透力,提高炔雌醚药饵的抗生育作用,有望开发为具有良好应用前景的不育剂配方。

一种复方避孕药物对三种野鼠的不育效果

本文首次报道一种由左炔诺孕酮和雌醚配伍制成的复方避孕药物 (代号 :EP 1 )对雌性布氏田鼠、灰仓鼠和子午沙鼠的不育效果 ,目的在于检验其能否用于野鼠的生育率控制。该不育剂的适口性为对照饵料的6 1 % ,对雌性布氏田鼠的繁殖具有明显的抑制作用 ,表现在使产仔时间延迟约 3d、产仔率降低 4 0 % - 5 0 %。两次间隔给药方式比连续给药方式的效果好。该复方避孕药物可以显著降低灰仓鼠、子午沙鼠的产仔率和产仔窝数 ,也显著降低子午沙鼠的每窝产仔数 ;对灰仓鼠、子午沙鼠不育效果可达 3个月。该复方避孕药物对灰仓鼠的不育效果优于子午沙鼠 ,对子午沙鼠尚有一定的致死作用。因此 ,EP 1在野鼠生育率控制上有一定应用潜力 ,建议采用两次间歇投饵 ,或者一次饱和投饵 (影响 2 - 3个动情周期 )

EP-1包合物制备及其对布氏田鼠繁殖器官的影响

EP系列鼠类不育剂的主要成分——左炔诺孕酮和炔雌醚在常温下难溶于水,给研究和应用造成很大不便。本研究利用2-羟丙基-β-环糊精(HPCD)提高了EP不育剂的水溶性,制备包合物;设置4个浓度梯度的EP-1包合物水溶液,分别对雌雄布氏田鼠进行灌胃,并在第2周和第4周测量繁殖器官指标,评价不育效果。结果表明,在20%的HPCD水溶液中,左炔诺孕酮和炔雌醚的溶解度分别可达约4 mg/mL和0.5 mg/mL;在第2周,2 mg/kg EP-1灌胃组雄鼠的繁殖器官受到了明显抑制,但各剂量组雌鼠未表现出明显影响。本研究结果说明,HPCD与EP-1可通过形成包合物,显著增加其常温下的溶解度;EP-1包合物对雄性布氏田鼠的繁殖器官有抑制效果,但是对雌鼠作用不明显。本研究结果表明包合作用未影响EP系列不育剂的不育效果。

一种复方避孕药物对围栏内大仓鼠种群繁殖力的影响

本文报道了由左炔诺孕酮和炔雌醚配伍制成的复方避孕药物(代号EP-1)对围栏内大仓鼠种群繁殖力的影响。实验分为4个组对照组、0.001%毒饵组、0.003%毒饵组和0.003%毒饵预处理组,并各设有一组重复。于2001年6月,在每组围栏内各放入5雄5雌成年大仓鼠,检验投放EP-1毒饵后对大仓鼠繁殖力的影响。至9月份,2个对照组新出生鼠数量均为12只,平均每雌繁殖力为2.4;而所有6个EP-1处理组新出生鼠数量均为4只或以下,平均每雌繁殖力在0.4～0.8之间。结果表明,处理组大仓鼠的繁殖力明显受到了不育剂EP-1的抑制。在半自然状况下,投放足量的EP-1毒饵可以有效降低大仓鼠种群的繁殖力和数量。

炔雌醚对雄性长爪沙鼠不育效果及其可逆性

为探讨炔雌醚对雄性长爪沙鼠生殖器官及繁殖的影响,将试鼠随机分为多剂量组、单剂量组和对照组。多剂量组以每次3.5mg/kg·BW(5次/周,2周)、单剂量组以35mg/kg·BW炔雌醚灌胃。处理后15d、30d、60d、90d剖检,观察性腺系数、精子质量和繁殖率等指标,H·E染色观察附睾组织病理学变化。结果表明:与对照相比,炔雌醚处理后15d、30d给药组试鼠睾丸、附睾及精囊腺极度萎缩(P<0.01),精子密度、精子活力和活精子百分率明显下降(P<0.01),精子畸形率显著上升(P<0.01),附睾管腔内充满大量发育异常的精子细胞,繁殖率显著下降;与单次给药相比,多次连续给药对试鼠生殖器官影响更严重。处理后60d,除多剂量组附睾外,各组性腺基本恢复至对照水平,单剂量组、多剂量组精子质量及繁殖率与对照仍有极显著差异(P<0.01)。90d后试鼠各项指标及繁殖率均恢复正常,表现为可逆性。结果表明:该药对长爪沙鼠不育效果明显;多次低剂量给药较单次高剂量给药不育效果更好;90d后,炔雌醚对生殖器官和繁殖的影响能够恢复正常。

复方避孕药物(EP-1)对雄性大仓鼠繁殖器官的影响

We first report the effect of a compound EP-1 (mixture of levonorgestrel and quinestrol) on male greater long-tailed hamsters (Tscherskia triton). Hamsters in the treatment group were provided with wheat baits with 0.001% EP-1 for six consecutive days, while hamsters in the control group were provided with plain wheat. One week and three weeks later, reproductive organs of hamsters of both groups were measured, respectively. We found the size or weight of testis, spermatophore and epididymis of the treatment group were significantly reduced compared to those of the control group, and this reduction was greater in the third week compared to that of the first week. The results indicate that EP-1 is able to reduce the fertility of both male and female hamsters.

左炔诺孕酮炔雌醚片所致动情期同步的雌性小鼠的研制

目的 促使NIH雌性小鼠的动情期同步出现 ,同时避免其与雄性小鼠交配后受孕。方法 用左炔诺孕酮炔雌醚片灌胃 ,并以已烯雌酚作为对照药 ,比较雌性小鼠动情期同步出现的几率 ,寻找出制作同步动情期的雌性小鼠的最佳造模方法。结果 发现左炔诺孕酮炔雌醚片的灌胃剂量为人体的 2倍 ,且每 5天灌胃一次 ,雌性小鼠的动情期同步几率就可以达到 80 %或以上。结论 本研究为房室不节致肾虚证雄性小鼠模型所需同步动情期雌性小鼠的制作提供了较为简便的方法。

两种不育剂对长爪沙鼠的作用

研究贝奥雄性不育剂和左炔诺孕酮-炔雌醚复合雌性不育剂对长爪沙鼠（Meriones unguiculatus）的作用.结果表明：雄性不育剂25～100 mg/kg可使精子密度和活力下降,200 mg/kg以上可致试鼠半数以上死亡;复合雌性不育1mg/kg即可致半数以上试鼠出现子宫水肿,5和10 mg/kg则出现子宫水肿,同时在子宫外壁形成淤血瘢,60和10 mg/kg即出现死亡.

人用不育剂对小鼠繁殖的影响

用北京紫竹药业有限公司2001年生产的左炔诺孕酮炔雌醚(复方18 甲)和北京制药厂1991 年生产的甲基炔诺酮速效避孕片,按不同剂量采用一次性灌胃法给ICR雌性小鼠用药,观察386 d.结果表明,使用复方18 甲1 mg/kg剂量组的小鼠生育率为100%,平均控制生育时间为21.8 d,平均产仔数降低1.6只;使用过期甲基炔诺酮1 mg/kg剂量组的小鼠生育率为100%,同笼后距产仔平均时间是对照组的1.6倍,平均控制生育时间为15.3 d,且未见致死现象;由使用复方18 甲和甲基炔诺酮2 mg/kg剂量组开始,随着剂量的增加,小鼠的生育率、平均产仔数、首次生育增殖率、平均存活时间均下降,死亡鼠数、致死率、同笼后距产仔平均时间、平均控制生育时间均增大;使用复方18 甲8 mg/kg以上剂量组的小鼠平均控制生育时间达到0.5 a,使用复方18 甲32 mg/kg剂量组的小鼠平均控制生育时间可以控制在1 a以上,但致死率达100%,平均存活时间为81.8 d;使用过期甲基炔诺酮4 mg/kg剂量组的小鼠生育率为57.1%,平均控制生育时间近0.5 a,使用过期甲基炔诺酮8 mg/kg剂量组的小鼠生育率为28.5%,致死率达71.4%,平均控制生育时间超过0.5 a,使用过期甲基炔诺酮64 mg/kg剂量组的小鼠生育率为0,致死率为100%,表明不育剂在高剂量时对鼠类有直接的灭杀作用。

2种不育剂和1种抗凝血剂对藏北草原高原鼠兔的控制效果

2012年4月至2013年4月在藏北草原进行了炔雌醚、莪术醇和增效敌鼠钠盐控鼠试验。均配制成青稞药饵,投放药饵后第20、75和350天进行控效调查。结果显示:炔雌醚具杀灭高原鼠兔作用,20d校正灭效达72.24%,对成年雌雄鼠繁殖器官均能起到明显损坏作用,且适口性最好;增效敌鼠钠盐控鼠效果最好,20d校正灭效达94.46%;莪术醇也有一定效果,75d幼体比最低,总体看,3种药物均具有一定控制效果,有一定实际应用潜力,但还需进一步试验验证其控鼠效果。

炔雌醚对布氏田鼠繁殖的抑制效果

明确炔雌醚对鼠类繁殖抑制最适剂量及持续有效作用时间,对其后续相关理论研究和实践应用具有基础性作用。本研究以0.5 mg/kg、1.0 mg/kg、2.0 mg/kg、3.0 mg/kg、6.0 mg/kg浓度炔雌醚分别连续灌胃雄性和雌性布氏田鼠7 d后,与正常异性配对观察90 d。按繁殖启动期、繁殖率和繁殖力等最直观的指标综合评价了5个浓度炔雌醚对雌雄布氏田鼠的不育效果。室内条件下,炔雌醚能够延迟雌雄布氏田鼠的生殖启动,但可能由于样本量小,未达统计显著性。90 d内,一定浓度的炔雌醚能够降低雌雄个体的繁殖率和平均每窝产仔数,同样未达统计显著性。一些浓度的药物能够显著降低布氏田鼠的繁殖力,其抑制效果无剂量相关性。推断炔雌醚对雄性布氏田鼠的最适不育作用浓度为2.0 mg/kg左右,对雌性的最适不育作用浓度为1.0 mg/kg左右。实际综合应用剂量2.0 mg/kg左右,能有效降低布氏田鼠产仔总数,其持续时间可达90 d。