Influence of dimethoate on testicular and epididymal organs, testosterone plasma level and their tissue residues in rats.

The effect of dimethoate at two dosage levels (6.25 and 12.50 mg/kg b. wt.) on male reproduction tissues and their tissue residues in rats were studied. The tested doses were given orally to male rats for 65 consecutive days. Sex organs weight analysis, semen picture, testosterone levels and histopathology of the male genital organs were the criteria used to evaluate the reproductive efficiency of the treated rats. There was a dose-related decrease in the weights of most genital organs and sperm motility associated with an increase in the percentages of dead and morphologically abnormal spermatozoa of treated rats. A decrease in plasma testosterone levels was observed in the treated groups. Histological examination revealed that dimethoate caused testicular lesions characterized by moderate to severe degenerative changes of spermatogonial cells and by partial arrest of spermatogenesis. Sections from liver revealed that the central veins and hepatic sinusoids appeared dilated, with some areas of haemorrhage. The highest concentrations from dimethoate were found in liver and tests and the lowest in skeletal muscle. Dimethoate and its metabolite analog were still present in a detectable concentration 21 days after stopping its oral administration.     

Effects of experimental cryptorchidism on sperm motility and testicular endocrinology in adult male rats

The effect of induced cryptorchidism on testicular function and sperm motility was investigated. Bilateral cryptorchidism was created surgically in adult male rats (treated group), and sham-operated rats were used as a control group. Five rats from each group were sacrificed on days 1, 3, 5, and 7 after surgery. The percentage of motile spermatozoa began to decrease 1 day after the operation, followed by an abrupt decline 3 and 5 days later in cryptorchid rats. Furthermore, there were significant decreases in the other sperm motility parameters 5 days after inducement of cryptorchidism. In cryptorchid rats, plasma concentrations of LH, FSH, testosterone, and inhibin B were significantly lower than in the control group 1 day after the operation. Thereafter, plasma concentrations of LH, FSH, and testosterone gradually increased in the cryptorchid rats. On the other hand, plasma concentrations of inhibin B showed a further decline from day 3 after the operation onward. Concentrations of immunoreactive (ir)-inhibin, but not testosterone, in testicular interstitial fluid were remarkably increased until 3 days after surgery in the cryptorchid rats, and declined thereafter. Testicular response to human chorionic gonadotropin (hCG) for testosterone release was decreased in the cryptorchid rats compared with the control rats, indicating that heat stress to testes resulted in a reduction of the activity of Leydig cells and Sertoli cells. These results clearly indicate that heat stress to the testes resulted in a significant reduction of sperm activity within 3 days, and this was followed by changes in testicular endocrine function.     

Inhibitive effects of quinestrol on male testes in Mongolian gerbils (Meriones unguiculatus)

The current study evaluated effects of quinestrol on oxidative stress and abnormal spermatogenesis for male Mongolian gerbils. Gerbils were randomly divided into multi-dose treated, single-dose treated, control groups. At 15 days after treatment antioxidant enzymes (SOD, GSH-Px) activities and T-AOC were decreased whereas the MDA concentration was significantly increased, testicular weight and seminiferous tubular areas decreased, germ cells were rarefied and showed irregular distribution in seminiferous tubules, apoptosis was pronounced among spermatocytes and spermatids, the number of dead and abnormal acrosomes of spermatozoa increased significantly in quinestrol treated groups. At 30 days following treatment the testicular histopathological changes were more severe, sperm quality and antioxidant capacity continued to decline, and multi-dose treatment produced more damage to gerbils testes compared with single-dose treatment. The physiological indicators were recovered by 60 days of treatment withdrawal. The results showed oxidative stress induced by quinestrol in relation to abnormal spermatogenesis.     

Effect of Daily Food Supplementation with Essential Fatty Acids on Canine Semen Quality

Polyunsaturated fatty acids are important membrane components that influence membrane integrity and fluidity. In the present study, the effect of oral supplementation for 60 days with essential fatty acids (omega 3, 6 and 9) and vitamin E on canine semen quality was evaluated. Sixteen dogs were selected for the experiment; eight were used as the control group and eight received the fatty acid supplemented diet for 60 days. Semen samples were taken every 15 days during the entire experimental period and were analyzed for volume (ml), motility (%), vigour (0–5), concentration (×10⁶/ml), morphology of spermatozoa (%), plasma membrane integrity (%; using the hyposmotic swelling test) and thermoresistance (motility and vigour after 4 h at 38°C). We concluded that, daily supplementation with omega 3, omega 6 and omega 9 fatty acids, together with vitamin E, for a period of 60 days, significantly increased the semen volume of the treated group after 15 days of supplementation; the vigour and concentration of spermatozoa were superior after the first month of supplementation, while the percentage of morphologically abnormal spermatozoa decreased and the cells were protected against thermal stress.     

当归补血汤提取物亚慢性毒性试验研究

试验旨在评价当归补血汤提取物安全性,为临床安全用药提供试验依据。选取120只SD大鼠（雌雄各半）随机分为高、中、低剂量组和空白对照组,药物组分别按60、30、15 g/kg体重剂量灌胃给药,空白对照组给予等体积蒸馏水,连续给药28 d,停药后观察14 d。结果显示,给药结束时,高剂量组雄性大鼠出现体重增长减缓（P < 0.01）和饲料消耗量降低（P < 0.01）,雄性大鼠白细胞数（WBC）、淋巴细胞（Lym）均显著升高（P < 0.05）,丙氨酸氨基转移酶（ALT）、总胆固醇（TC）、葡萄糖（GLU）均极显著降低（P < 0.01）,血小板（PLT）显著减少（P < 0.05）;雌性大鼠红细胞（RBC）、血红蛋白（HGB）、ALT均极显著减少（P < 0.01）。中剂量组大鼠ALT和碱性磷酸酶（ALP）显著或极显著降低（P < 0.05;P < 0.01）。停药第14天雄性大鼠网织红细胞（RET）显著增多（P < 0.05）,雌性大鼠HGB显著减少（P < 0.05）。停药后可恢复正常,其余相关检测指标均未见异常。各脏器组织病理学检查均未见异常。结果表明当归补血汤提取物毒性低,可以安全用于动物。     

Time course of endocrine changes in the hypophysis-gonad axis induced by hypobaric hypoxia in male rats

Chronic hypobaric hypoxia (CHH) induces a decrease in sperm output and spermatogenesis in male rats. The mechanisms that underlie these changes in testicular function are unknown and could involve changes in the hypophysis-gonad axis. We have tested the hypothesis that changes take place in the endocrine status (FSH, follicle stimulating hormone; LH, luteinizing hormone; testosterone) of rats subjected to CHH. Male Wistar rats were maintained under normobaric or hypobaric conditions (428 torr, 4,600 m). On days 0, 5, 15 and 30 post-exposure, 12 rats were anesthetized, their body weights were measured and blood samples were collected. The testicles were fixed in 4% formaldehyde and processed for histological analysis. In this time course, the FSH levels rose by day 5 post-exposure. On subsequent days, the FSH levels decreased in rats subjected to CHH with a tendency to remain higher than the normoxic group. The LH plasma levels decreased in rats exposed to CHH. Consistent with the decrease in LH levels, the plasma testosterone level decreased significantly after 30 days of CHH exposure. Integrated analysis of hormonal changes in rats subjected to CHH and the body dehydration that occurs in HH allows us to conclude that the effects of CHH on spermatogenesis may be partially related to changes in the hypophysis-gonad hormonal axis.     

Study on Subacute Toxicity Test of the Extact of Dangguibuxue Tang

To evaluate the safety of the Dangguibuxue Tang (DBT) for animals, SD rats were administrated DBT by gavage once daily at 0, 15, 30 and 60 g/(kg·BW) for 28 consecutive days as control, low, medium and high dosage groups, and followed by a 14-day recovery period. The results showed that compared with control group, the weight gain and food intake of male rats in the high dosage group were extremely significantly decreased (P < 0.01). WBC and Lym of male rats in the high dosage group were significantly increased (P < 0.05), whereas ALT, TC and GLU were extremely significantly decreased (P < 0.01),PLT was significantly decreased (P<0.05). RBC, HGB and ALT of female rats in high dosage group were extremely significantly decreased (P < 0.01). ALT and ALP of rats in medium dosage group were significantly or extremely significantly decreased (P < 0.05;P < 0.01). While in medium dosage group RET of male rats was significantly increased (P < 0.05) and HGB of the female rats were significantly decreased (P < 0.05) 14 days after withdrawal. However, these indexes had no significant difference to control group at the end of recovery period. In addition, no changes were observed in the main organs of rats at macroscopic and microscopic level. The result showed that subacute administration of DBT was not toxic in SD rats, suggesting a safety use for animals.     

Effects of exposure to electromagnetic field (1.8/0.9 GHz) on testicular function and structure in growing rats

The aim of our study was to evaluate the possible effects of whole-body electromagnetic field (EMF) exposure on reproduction in growing male rats. Male albino Wistar rats (2 days old) were exposed to EMF 1800 and 900 MHz for 2 h continuously per day for 90 days. Sham control was kept under similar conditions except that the field was not applied for the same period. After blood samples were collected, the animals were sacrificed 24 h after the last exposure and the tissues of interest were harvested. The mean plasma total testosterone showed similarity among the two study groups and was significantly higher than the sham control rats. The percentage of epididymal sperm motility was significantly higher in the 1800 MHz group (P<0.05). The morphologically normal spermatozoa rates were higher and the tail abnormality and total percentage abnormalities were lower in the 900 MHz group (P<0.05). Histopathologic parameters in the 1800 MHz group were significantly higher (P<0.05). In conclusion, the present study indicated that exposure to electromagnetic wave caused an increase in testosterone level, epididymal sperm motility (forward), and normal sperm morphology of rats. As a consequences, 1800 and 900 MHz EMF could be considered to be a cause of precocious puberty in growing rats.     

不同平衡时间对獭兔精液冷冻保存效果的影响

为探讨獭兔精液冷冻保存适宜的平衡时间,将精液稀释后分别平衡30 min、60 min、90 min、120 min后装管,并进行冷冻保存,解冻后分析精子活率、畸形率、质膜完整率和顶体完整率四个指标.结果表明,平衡60min时冻后精子活率（0.30）显著高于30 min（0.15）、90 min（0.21）和120 min（0.15） （P＜0.05）;畸形率显著低于30min（16.16％ vs26.23％）（P＜0.05）,但与其他各组差异不显著（P＞0.05）;平衡30 min、60 min时精子质膜完整率显著高于120min（83.05％、81.79％ vs74.79％） （P＜0.05）,与90 min差异不显著（83.05％、81.79％ vs78.63％）（P＞0.05）;不同平衡时间组精子顶体完整率差异均不显著（P＞0.05）.综合分析表明,獭兔精液在冷冻时适宜的平衡时间为60 min.     

天冬糖苷散急性毒性及亚慢性毒性研究

试验旨在通过天冬糖苷散对小鼠的急性毒性试验和大鼠亚慢性毒性试验,评价该药物制剂的安全性。在急性毒性试验中,分别进行了预试验（5 000、1 000、200、40 mg/（kg·BW））,正式试验（5 000、2 500、1 250、625 mg/（kg·BW））和最大给药量试验（60 g/（kg·BW））。给药后,连续7 d观察小鼠精神状态和死亡情况,试验结束后对小鼠进行剖检。在亚慢性毒性试验中,将80只Wistar大鼠,随机分为4组,即高剂量组（10 g/（kg·BW））、中剂量组（5 g/（kg·BW））、低剂量组（2.5 g/（kg·BW））和对照组,各组连续给药30 d,试验期间每天观察大鼠的临床表现,并记录大鼠的体重、摄食量和饮水量,计算增重率。给药30 d后,采集血液进行血常规和血液生化指标检测,剖检并计算脏器系数,并对主要脏器进行组织病理学检查。结果显示,在急性毒性试验的预试验、正式试验和最大给药量试验中均未出现小鼠死亡,剖检脏器无肉眼可见病变。在亚慢性毒性试验中,天冬糖苷散中、低剂量组受试大鼠体重、血液学指标、血液生化指标、脏器系数和组织病理学检查结果与对照组相比均无显著差异（P>0.05）。高剂量组雄性大鼠红细胞平均体积（MCV）、丙氨酸转氨酶（ALT）含量均显著高于雄性对照组（P<0.05）;红细胞计数（RBC）、红细胞分布宽度（RDW）、单核细胞百分率（MONO%）均显著低于雄性对照组（P<0.05）,但在正常范围内,且各脏器病理组织学检测结果与对照组无显著差异（P>0.05）,表明10 g/（kg·BW）剂量天冬糖苷散对受试大鼠的血液学指标和肝肾功能有一定影响。以上结果表明,天冬糖苷散对小鼠的LD₅₀>5 000 mg/（kg·BW）,天冬糖苷散在10 g/（kg·BW）范围内连续灌胃大鼠30 d,对大鼠无明显毒副作用,安全性好。     

不同处理对白刺花种子萌发效果的影响

以白刺花种子为材料,分别采用砂纸摩擦,30％NaOH浸种0．5、1、1．5、2、2．5、3h,90％NaOH浸种5、15、25、35、45、55min,98％浓硫酸浸种10、20、30、40、50min对种子进行硬实处理,在室温（25～28℃）下进行发芽试验。结果表明：砂擦处理效果最好,发芽率为80％;98％浓硫酸处理...     

Role of ginger against the reproductive toxicity of aluminium chloride in albino male rats

The aim of the current study was to evaluate reproductive disorders concomitant with aluminium chloride (AlCl₃) toxicity in Albino male rats. Attention was also directed to study the protective influence of ginger against this toxicity. Forty‐five mature Albino Wistar male rats were equally divided into three groups; the first group was served as control group while those of the second group (AlCl₃) were daily treated with 34 mg/kg bw. AlCl₃ orally. The third group (AlCl₃ + ginger) was treated daily with AlCl₃ as in group 2 in combination with ginger (40 mg/kg bw), which started 2 weeks prior to AlCl₃. Five animals from each group were sacrificed on days 30, 45 and 60 of treatment. AlCl₃ administration significantly decreased serum testosterone levels, increased testicular homogenate malondialdehyde and deteriorated semen picture with increased testicular DNA fragmentation. Histopathological examination revealed degenerative changes of the seminiferous tubules with focal areas of necrosed spermatogenic cells, marked degeneration and desquamation of the lining epithelial cells of epididymis as well as multiple calcified material in prostate gland following 60 days of aluminium treatment. Ginger treatment started to improve significantly all studied parameters after 60 days as compared with AlCl₃‐treated group. In the current study, it was concluded that AlCl₃ had a destructive effect on all the studied reproductive parameters. Treatment with ginger has an ameliorating effect against AlCl₃ toxicity after 60 days post‐treatment.     

Effect of administrating oxytocin or prostaglandin F2alpha on characteristics of the canine ejaculate

To test the hypothesis that male dogs treated with smooth muscle contracting drugs have an increase in the total number of spermatozoa in the ejaculate but no change in all other ejaculate characteristics, such as progressive motility of spermatozoa or percentage morphologically normal spermatozoa, dogs were treated with oxytocin or prostaglandin F2alpha (PGF2alpha) and compared to saline treatments. Semen was collected from each of the 3 dogs once every 3 to 4 d for a total of 6 collections per dog. Ten minutes before each collection, 1 of 3 injections (oxytocin 10 IU [0.5 mL], IM; PGF2alpha 2.5 mg [0.5 mL], IM; or saline 0.5 mL, IM) was administered. Compared to the saline controls, neither treatment had any significant effect on any measured variable when collected in this manner with an estrus bitch present. Therefore, the use of these drugs does not appear to be a viable treatment to increase the number of spermatozoa.     

Sperm viability in ram semen diluted and stored in three different extenders.

Semen was collected with an artificial vagina from 4 one-year-old rams, in order to study the changes in sperm motility and membrane integrity of spermatozoa split-diluted and stored at 5 degrees C during 7 days in sodium citrate, Tris, and milk-based extenders, respectively. Sperm motility was assessed subjectively and sperm membrane integrity was determined using the fluorescent probes Calcein-AM and Ethidium homodimer. Representative samples were studied using scanning electron microscopy (SEM). The average incidence of sperm motility decreased over time in all the extenders (p < 0.001). The incidence of spermatozoa showing progressive motility and intact plasma membrane was significantly higher in semen diluted with sodium citrate than in the other 2 extenders following 4 days of dilution until the end of the study. Evaluation with SEM confirmed the findings obtained with the supra vital fluorescent dyes. The results of the present study indicated that there were no differences between sodium citrate-, Tris- or milk-based extenders when ovine liquid semen was stored at 5 degrees C during a short period (2 days). However, when semen was stored for longer time, spermatozoa in the sodium citrate-based extender sustained its viability better.     

Evaluation of spermiation indices with multiple sperm collections in endangered sterlet (Acipenser ruthenus)

This study investigated the effects of multiple collections of sperm on endangered sterlet (Acipenser ruthenus) sperm functional parameters [spermatozoa motility and curvilinear velocity (VCL)] as well as on protein concentration and osmolality of seminal plasma. The average sperm volume and mean spermatozoa concentration per male were significantly altered with multiple collections. On the other hand, no significant effect of multiple collections on protein concentration of seminal plasma was observed. In all experimental groups, moderate impact of sequential collection on osmolality (p < 0.05) of seminal plasma was observed. Ninety to 100% of motile spermatozoa were observed at 15 s after activation, with an average VCL of 181.12 ± 19.10 μm/s. After 90 s, average VCL decreased to 130 ± 26 μm/s. Motility was maintained for up to 4 min. The maximum percentage of motile spermatozoa was observed after the third collection of sperm. The spermatozoa VCL increased significantly with subsequent collections. The results of this study provide new data on the effects of multiple collections on quantitative and qualitative parameters of sperm in sterlet. The data confirmed that the sequential stripping has no negative effect on the percentage of motility and spermatozoa velocity. This should be beneficial for the development of sterlet aquaculture programs.     

Interrelationships between athyreotic and manganese-deficient states in rats.

Possible interrelationships of manganese-deficient and hypothyroid (thiouracil treatment) states in rats were examined. Clinical signs, necropsy changes, and plasma thyroxine concentrations were determined in control rats (group A), thiouracil-treated (hypothyroid) rats (group B), rats given manganese-deficient feed (group C), and rats given thiouracil and manganese-deficient feed (group D). Clinical signs observed included a hyperemic condition of the ears in group C and D rats that was considerably more severe in the latter group. One rat from group D also had middle ear changes, as reflected by a tilting of the head. Fluid intake was severely reduced in group D rats near the end of the 60-day experimental period and resulted in marked dehydration. Pathologic change (fatty liver) was observed at necropsy in only 1 rat from group D. Thiouracil treatment of rats reduced plasma thyroxine concentration to 48 to 68% of base line from experimental days 20 to 60. The same thiouracil treatment combined with feeding a manganese-deficient ration significantly reduced plasma thyroxine concentrations to 37% of base line at day 20 and 5% of base line at day 40; the concentration at day 60 was 76% of base line, apparently approaching normal because of concentration of the plasma (and thyroxine) in the dehydrated rats. Mean adrenal gland weight was significantly less than normal in group D rats, whereas mean thyroid gland weight in this group was increased, although less than that of group B rats treated with thiouracil only. Thus, clinical signs of deficiency were enhanced when athyreotic and manganese-deficient states were combined, and plasma thyroxine concentrations were markedly decreased, giving added meaning to the need for awareness of hormonal and trace mineral status of animals.     

Effect of vitamins,probiotics and protein level on semen traits and seminal plasma biochemical parameters of post-moult male broiler breeders

1. A study was designed to investigate the comparative effect of supplementary vitamin E, vitamin C, probiotics and dietary crude protein concentration on semen traits and seminal plasma biochemical parameters in male broiler breeders after Zn-induced moulting.

2. A total of 180 male broiler breeders were induced to moult at 65 weeks of age by mixing ZnO in diet at the rate 3000?mg/kg of feed. After moulting, the males were divided into six groups that were given feed supplemented with: vitamin C (500?IU/kg), vitamin E (100?IU/kg), protein (140?g CP/kg), probiotics (50?mg/kg) and the combination of these components, while one group was kept as a control. Semen samples were collected weekly and semen volume, spermatozoa concentration, motility and dead spermatozoa percentage were determined. Seminal plasma was separated to determine the concentration of total antioxidant capacity (TAC), homocysteine, paraoxonase (PON1), arylesterase, ceruloplasmin, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities.

3. Semen volume was significantly higher in the vitamin E and C groups compared to the control. Spermatozoa motility was higher in the vitamin E group and dead spermatozoa percentage was significantly lower in the vitamin C group compared with the control group.

4. Seminal plasma TAC was higher in the vitamin E group, homocysteine was lower in the vitamin C and E groups. PON1 was higher in the combination group. Arylesterase increased significantly in the vitamin C and combination groups over time. Seminal plasma AST was significantly lower in the vitamin C and E supplemented groups whereas ALT decreased significantly only in the vitamin E group compared with the control. Higher concentrations of ceruloplasmin were observed in the combination group compared with the other treatments.

5. It was concluded that additional vitamin E and C or their combination was the most potent nutrient treatment for improving the semen traits and seminal plasma biochemical characteristics in male broiler breeders after Zn-induced moulting.     

连续低剂量黄曲霉毒素B1对大鼠肝肾损伤作用

用含有不同质量浓度黄曲霉素B1（AFB1）（0、4、20、25、50μg／kg）的污染饲料连续饲喂各试验组大鼠60d,于7、15、30、60d静脉取血,测定各组大鼠肝功能与肾功能生化指标。每周检测大鼠体质量,试验第60天断头处死大鼠,检测肝肾组织病理学变化并计算各组大鼠的脏体系数。试验期间备组受试动物未发现明显的中毒症状和异常情况,60d内无受试动物死亡。与对照相比,不同剂量组AFB1对大鼠体质量无显著性影响;连续喂饲7d,大鼠血清AST和BuN含量显著升高（P〈0．05）;连续喂饲15d,大鼠血清AsT、BUN和ALB含量显著升高（P〈0．05）,连续喂饲30d,大鼠血清BUN含量显著升高（P〈0．05）,连续喂饲60d,大鼠血清CR和BUN含量显著升高（P〈0．05）。在各测试质量浓度条件下,大鼠虽未发现明显的中毒症状和异常情况,试验期间无动物死亡,但与空白对照相比,各剂量组AFBl对大鼠均产生了显著的肝肾组织病理学损伤,中毒程度与给毒剂量成正相关性。随着毒素暴露时间延长,大鼠肝脏对低剂量AFBl表现出一定的耐受性,而大鼠的肾脏损伤与毒素暴露时间表现出显著的积累效应。     

Oral administration of Kaempferia parviflora did not disturb male reproduction in rats

To investigate the androgenic effect of Kaempferia parviflora (KP), a Thai herbal plant, adult male rats were randomized into control and KP-treatment groups. Rats were treated orally with water in the control group and with 1,000 mg/kg/day of KP in the treatment group for 45 days. Blood samples were collected on days 10, 20, 30 and 45 for measurement of the serum follicle stimulating hormone (FSH), luteinizing hormone (LH), testosterone, progesterone and corticosterone levels. The reproductive and non-reproductive organs were dissected on day 45 and weighed. Mating behavior was also observed on days 20 and 30. Body weight was measured throughout the study period. The results showed that KP induced an increase in body weight compared with the controls. There were no significant differences in the weights of either reproductive (testis, seminal vesicle plus coagulating gland, levator ani muscle plus bulbocarvernosus muscle and glans penis, except the prostate gland) or non-reproductive organs (kidney, adrenal gland and gastracnemius muscle). There were no significant differences in serum levels of either FSH or LH between the two groups. The serum testosterone and progesterone levels were insignificantly lower in the KP group during the first 30 days. The serum corticosterone levels in the KP group were lower than those in the controls throughout the study period and were significantly low on days 20 and 30. There were no significant changes in mating behavior in the rats treated with KP. Although KP affected the body weight and serum corticosterone level, it did not affect mating behavior, reproductive and non-reproductive organ weights or hormones related to the reproductive system in the adult male rats. Therefore, we conclude that the testosterone-like effect of KP did not disturb the hypothalamic-pituitary-testicular axis or male reproduction.     

Induction of superovulation by immunoneutralization of endogenous inhibin in immature rats

The effects of passive immunoneutralization of endogenous inhibin on ovulation rate in immature rats were investigated. Efficiency of superovulation on production of fertilized oocytes was compared between the inhibin antiserum (inhibin-AS) and equine chorionic gonadotropin (eCG) protocols. Immature female Wistar strain rats were superovulated with a single injection of 100-200 microl inhibin-AS, with and without an injection of human chorionic gonadotropin (hCG). A total of 77.8% of the 26-30-day-old rats treated with a single injection of 100-200 microl inhibin-AS ovulated 72 h after treatment, while rats given normal goat serum (NGS; 200 microl) did not ovulate. At 28 days of age, all of the inhibin-AS treated rats ovulated when additional hCG treatment was given, whereas the number of ovulated oocytes was not affected. The number of ovulated oocytes in the inhibin-AS-hCG treated groups was significantly higher than that of the NGS-hCG treated group. In addition, plasma concentrations of FSH in the inhibin-AS-hCG treated group significantly increased compared with the NGS treated group. While the percentage of mated rats in the 200 microl inhibin-AS-hCG treated group was significantly lower than that of the 15 IU eCG-hCG treated group, the fertilization rate was comparable between the two groups. The number of fertilized oocytes in the 200 microl inhibin-AS-hCG treated group was significantly higher in comparison with the 15 IU eCG-hCG treated group. These results suggest that immunoneutralization of endogenous inhibin could be a reliable method for induction of superovulation to collect a large number of normally fertilized oocytes in immature rats.