Prolonged Estrus Research Articles

Obese Neuronal PPARγ Knockout Mice Are Leptin Sensitive but Show Impaired Glucose Tolerance and Fertility.

The peroxisome-proliferator activated receptor γ (PPARγ) is expressed in the hypothalamus in areas involved in energy homeostasis and glucose metabolism. In this study, we created a deletion of PPARγ brain-knockout (BKO) in mature neurons in female mice to investigate its involvement in metabolism and reproduction. We observed that there was no difference in age at puberty onset between female BKOs and littermate controls, but the BKOs gave smaller litters when mated and fewer oocytes when ovulated. The female BKO mice had regular cycles but showed an increase in the number of cycles with prolonged estrus. The mice also had increased luteinizing hormone (LH) levels during the LH surge and histological examination showed hemorrhagic corpora lutea. The mice were challenged with a 60% high-fat diet (HFD). Metabolically, the female BKO mice showed normal body weight, glucose and insulin tolerance, and leptin levels but were protected from obesity-induced leptin resistance. The neuronal knockout also prevented the reduction in estrous cycles due to the HFD. Examination of ovarian histology showed a decrease in the number of primary and secondary follicles in both genotypes due to the HFD, but the BKO ovaries showed an increase in the number of hemorrhagic follicles. In summary, our results show that neuronal PPARγ is required for optimal female fertility but is also involved in the adverse effects of diet-induced obesity by creating leptin resistance potentially through induction of the repressor Socs3.

Perinatal Administration of a Selective Serotonin Reuptake Inhibitor Induces Impairments in Reproductive Function and Follicular Dynamics in Female Rat Offspring.

Up to 10% of pregnant women take antidepressants, of which selective serotonin reuptake inhibitors (SSRIs) are the most commonly prescribed. Using a rodent model, we investigated the reproductive impacts of perinatal SSRI treatment on reproductive cyclicity and function in female offspring. Virgin Wistar rats were given oral vehicle (n = 10) or fluoxetine hydrochloride (FLX, 10 mg/kg/d; n = 11) from 2 weeks prior to mating until weaning. Pubertal onset and reproductive cyclicity in offspring were assessed. Blood and ovarian tissues were collected for measures of reproductive function. Perinatal FLX tends to induce irregular reproductive cycles in adult offspring, which most commonly manifest as a prolonged estrus phase (FLX 34% vs control [CON] 10%) relative to CON offspring. The FLX offspring tended to have longer cycles (P = .052), had more secondary follicles (P = .0067), more total follicles (P = .0310), and increased apoptotic ovarian cells (P < .001). Prenatally exposed FLX offspring demonstrated elevated ovarian messenger RNA (mRNA) levels of ERβ (P = .008), Cry1 (P = .043), and tryptophan hydroxylase 2 (P = .024), independent of stage of cycle. Ovarian mRNA levels of brain and muscle Arnt-like protein 1 (P = .046) and Pet-1 (P = .021) were increased in FLX offspring a manner that was reproductive cycle stage dependent. This is the first study to investigate the postnatal effects of maternal perinatal exposure to FLX on adult offspring reproduction. We show that genes that regulate serotonin signaling and action in the ovary are altered in prenatally FLX-exposed offspring, which when coupled with increased expression of components of the core Circadian Locomotor Output Cycles Kaput (CLOCK) gene regulatory loop may suggest an interaction between serotonergic signaling and clock gene signaling pathways leading to the altered reproductive phenotype.

Granulosa cell tumours in the mare: A review of 52 cases

SummaryGranulosa cell tumour (GCT) is reported to be the most common ovarian neoplasm in the mare. A multicentre retrospective study evaluating the medical records of horses undergoing ovariectomy for treatment of aGCTwas undertaken, documenting the presenting clinicopathological features, treatment and outcome. Follow‐up information was obtained by telephone questionnaire. Fifty‐two mares were included. Most presented with behavioural/reproductive abnormalities, including stallion‐like behaviour (50%), aggression (31%), prolonged oestrus or nymphomania (19%), and persistent anoestrus (8%). Most (93%) affected ovaries had a multilocular appearance when examined ultrasonographically. Only 60% of horses with histopathologically confirmedGCTs demonstrated elevations in serum inhibin concentrations. Twenty‐five percent of horses had histopathologically confirmed bilateralGCTs. Ninety‐four percent of horses that underwent ovariectomy were discharged from the hospital. Standing laparoscopic ovariectomies had a lower complication rate (34%) than other surgical methods. Long‐term complications were uncommon (11%). In conclusion, histopathologically confirmedGCTs can occur in the presence of normal serum inhibin concentrations. The high prevalence of bilateralGCTs indicates that thorough evaluation of the contralateral ovary is necessary. Surgical ovariectomy for treatment ofGCTs has favourable short‐ and long‐term outcomes. Standing laparoscopic ovariectomy may be associated with a lower complication rate than other surgical methods.

Controlled breeding and reproductive management in water buffaloes (Bubalus bubalis) using Eazi Breed controlled internal drug release.

Buffalo reproduction is considerably affected by late maturity, poor oestrus symptoms and long postpartum periods. This study was undertaken to evaluate the efficiency of Eazi Breed controlled internal drug release (CIDR), an intravaginal progesterone-releasing device, in relation to oestrus and fertility. Five hundred true anoestrus buffalo cows, in the age group 4–6 years in 10 villages of Dharwad district in Karnataka state in India, were randomly selected and treated with CIDR for 9 days. Two mL of Cidirol (1 mg oestradiol benzoate) was administered intramuscularly to all animals on day 10. Forty-two buffaloes (8.4%) that failed to show oestrus signs (1.6%) or showed weak signs of oestrus (6.8%) after the first treatment were treated again 72 h after the Cidriol injection with a new device, and inseminated after the expression of oestrus. After the second treatment all the animals showed oestrus signs. The percentage of buffaloes showing intense oestrus was 67.40%, intermediate oestrus was shown by 25.80%, whilst 6.80% buffaloes showed weak oestrus even after the second treatment. The buffaloes showing oestrus signs were inseminated twice with an interval of 12 h, starting 12 h after the start of the oestrus signs. In 86 buffaloes showing prolonged oestrus signs a third insemination was done. The conception rates were 85.16%, 60.47% and 44.11% respectively in buffaloes showing intense, intermediate and weak oestrus. Transrectal palpation of the genital tract was performed 45–60 days post-insemination to diagnose pregnancy status, and in doubtful cases pregnancy was reconfirmed at 90 days after insemination. Out of 500 buffaloes treated in this way 380 animals became pregnant and the pregnancy rate was 76%. This study revealed the usefulness of Eazi Breed CIDR along with Cidirol treatment in buffaloes to improve their reproductive performance.

Prenatal Exposure to the Phytoestrogen Daidzein Resulted in Persistent Changes in Ovarian Surface Epithelial Cell Height, Folliculogenesis, and Estrus Phase Length in Adult Sprague-Dawley Rat Offspring

Daidzein (DZ), an isoflavone with the potential to interfere with estrogen signaling, is found in soy products, which have gained popularity due to purported beneficial effects on the cardiovascular and skeletal systems and potential antineoplastic properties. However, the ingestion of phytoestrogens has been associated with impaired reproductive function in many species. The aim of this study was to determine the long-term effects on the ovaries of rat offspring exposed to DZ or ethinyl estradiol (EE) during prenatal development. Gravid rats were administered either vehicle or 5 or 60 mg DZ/kg body weight/d or 0.002 mg 17-α EE /kg body weight/d on gestational days 6–21. Ovarian-related endpoints were investigated during adulthood in female offspring. The mean cell height of the ovarian surface epithelium was significantly reduced in all treated groups. Alterations in folliculogenesis included increased follicular atresia, a reduction in secondary and tertiary follicle numbers, and cyst formation. An elevated prevalence of a slightly prolonged estrus phase was also observed. The morphological changes to the ovarian surface epithelium are consistent with an antiproliferative effect, while ovarian folliculogenesis was adversely affected. The effects of the high dose DZ were similar to those observed with 17-α EE.

Optimizing estrous period characteristics of crossbred cows exhibiting prolonged estrus using a PGF2α analogue

The present study aimed at optimization of estrous period of prolonged estrus exhibiting crossbred cows (n=10) using PGF2α analogue (cloprostenol 500µg, i/m) administration between days 7 to 9 post-ovulation. Using a scoring chart, cows were scheduled for visual estrus detection, twice per day for 30 min. After each schedule, ultrasonography was done to detect the ovulation time. A scoring scale was used for the recording of visual estrus signs and estrus related alterations in the genital tract. During spontaneous-estrus (124.5±24h), ovulatory follicles had continuous growth before ovulation. During induced-estrus (32±3.5h), the maximum diameter of ovulatory follicle was similar to spontaneous- estrus. The corpus luteum (CL) exhibited slow regression during spontaneous-estrus. The inconsistent estrous score recorded during the extended estrous period was normalized at induced-estrus. In summary, the slow ovulatory follicle growth and CL regression could be associated with the persistence of estrous characteristics, which were optimized following PGF2α administration during early-luteal phase of cows.

Evaluation of serum anti-Müllerian hormone (AMH) in a Persian queen cat with bilateral cystic ovarian disease

Measurement of anti-Mullerian hormone (AMH) is applied to diagnose polycystic ovary syndrome in human. A 7-year-old female Persian cat was presented for persistent expression of behavioural oestrus. In response to examination of spines, the queen exhibited treading movements of hind legs. Trans-abdominal ultrasonography revealed a multicystic appearance of both ovaries. Oestradiol in the queen with prolonged oestrus (145 pg/ml) was higher than that in normal oestrous cats (50.8 ± 7.41 pg/ml). However, AMH concentration in the cat with prolonged oestrus (1.8 ng/ml) was within the range of AMH concentration in normal oestrous queens (3.5 ± 0.81 ng/ml; range, 1.2–5.8 ng/ml). The queen was diagnosed with cystic ovarian disease and was subjected to ovariohysterectomy. Excision and histopathology confirmed cystic ovarian disease as well as uterine hyperplasia. In conclusion, it seems that AMH could not serve as a diagnostic indicator of cystic ovarian disease in cat.

Goserelin can inhibit ovarian cancer proliferation and simultaneously protect ovarian function from cisplatin: an in vitro and in vivo study

This study investigates whether goserelin can inhibit ovarian cancer proliferation and protect ovarian function from cisplatin (CDDP). We evaluated proliferation and AKT phosphorylation in goserelin-treated ES-2 and SKOV3-ip ovarian cancer cells. Anti-Müllerian hormone (AMH) in human granulosa cells (hGCs) cotreated with goserelin and CDDP was measured by ELISA. Tumour volumes, Ki-67 expression, estrus, follicles, ovarian volumes, and serum AMH were compared in nude mice bearing transplanted tumours treated with goserelin and/or CDDP. Our results showed that goserelin inhibited cellular proliferation and AKT phosphorylation in vitro, and inhibited tumour growth and Ki-67 expression in vivo. Goserelin and CDDP cotreatment decreased the estrus cycles of the nude mice and prolonged estrus duration. Goserelin abrogated the CDDP-induced down-regulation of primary and preantral follicle percentage and ovarian volume. Goserelin increased AMH secretion in vitro and in vivo. In conclusion, goserelin inhibited ovarian cancer proliferation and simultaneously protected ovarian function from CDDP.

Nodular Dermatofibrosis in a Dog without a Renal Tumour or a Mutation in the Folliculin Gene

Canine nodular dermatofibrosis is a rare skin disease associated with renal cystadenoma or cystadenocarcinoma and uncommonly with uterine leiomyoma. It is generally seen in German shepherd dogs, but has been also reported in other breeds, and a relationship has been suggested with mutation of the gene encoding folliculin (FLCN), which is located on chromosome 5. A 10-year-old female golden retriever was presented because of numerous firm cutaneous nodules up to 4cm in diameter over the entire body surface. Cytological and histopathological examinations confirmed generalized cutaneous nodular dermatofibrosis, but ultrasonography of both kidneys ruled out renal neoplasia. Ovariohysterectomy was performed because of prolonged oestrus periods. Microscopical examination of the excised tissues confirmed the absence of uterine neoplasia, but identified rete adenoma of the right ovary. Abdominal ultrasound performed repeatedly over a 5-year follow-up period did not identify any alteration in the renal parenchyma. Molecular studies excluded the presence of any mutation in the FLCN gene.

Reproductive effects in F1 adult females exposed in utero to moderate to high doses of mono-2-ethylhexylphthalate (MEHP)

Phthalates are widely used as plasticizers in everyday products. Yet, studies on the effects of phthalates on female reproductive health are limited. In this study, pregnant C57/Bl6 mice were exposed via oral gavage to corn oil, 100, 500, or 1000mg/kg MEHP from gestational days 17–19. Reproductive lifespan was decreased by one month in the highest F1 exposure group (9.8±0.4 versus 11.1±0.6 months in control F1 females). F1 females exhibited delayed estrous onset at the two higher exposures and prolonged estrus was observed in all MEHP-exposed females. Serum FSH and estradiol were significantly elevated at the highest exposure and altered mRNA expression was found for the steroidogenic genes LHCGR, aromatase, and StAR. At one year of age, mammary gland hyperplasia was observed in high dose MEHP-exposed females. In summary, late gestational exposure to MEHP leads to multiple latent reproductive effects throughout murine life resulting in premature ovarian senescence and mammary hyperplasia.

Follicular cysts and prolonged oestrus in a female dog after administration of a deslorelin implant

CASE HISTORY: A 7-year-old female Bernese Mountain dog was presented for treatment to prevent oestrus. One 4.7-mg deslorelin implant was injected S/C between the shoulder blades. Three months later, the dog was re-examined because of prolonged oestrus. CLINICAL FINDINGS: Ultrasound showed multiple thin-walled cysts on both ovaries. Blood samples were taken at various intervals during the following weeks. Concentrations of oestradiol and vaginal smears indicated pro-oestrus. Follicle stimulating hormone (FSH) and luteinising hormone (LH) remained at basal concentrations. DIAGNOSIS: Follicular cysts and prolonged oestrus. TREATMENT: Two treatments of 360 IU human chorionic gonadotrophin (hCG) were administered 42 days apart, that induced a partial or complete degeneration of the cysts. However, concentrations of oestradiol rose again within a few weeks. After the second treatment with hCG the bitch developed pyometra. After successful conservative treatment with antibiotics and aglepristone the dog underwent ovariohysterectomy. CLINICAL RELEVANCE: Slow-release biocompatible implants containing deslorelin provide an opportunity for effective contraception for male dogs. Some authors describe deslorelin also as safe and efficacious for the use in female dogs but those recommendations are derived from few studies, with a small number of animals. Based on the outcome of this case and the experience of other authors we suggest a complete gynaecological examination be performed before implanting deslorelin, and weighing the risks against the advantages in controlling fertility. It is well known that the risk of induction of oestrus can be reduced when implants are administered at concentrations of progesterone in plasma of ≥16.0 pmol/L. The implant should be administered S/C, cranial and close to the umbilicus, to have the option of relocation and excision if necessary.

The Relationship Between Pregnancy Status and Production of IFN-Tau of Bovine Conceptus by Measuring Expression of Interferon-Stimulated Gene 15 (ISG15) of Peripheral Leukocyte in Cattle.

Conceptus of ruminant ungulate synthesizes and secretes interferon (IFN)-tau, which has been involved in maternal recognition of pregnancy. However, it remains unclear whether the positive relationship between the ability of IFN-tau secretion of bovine conceptus during the period of maternal recognition of pregnancy and its establishment of pregnancy. Recently, in sheep, it has been demonstrated that IFN-tau is released into the uterine vein and consequently induces expression of IFN-stimulated gene 15-kDa protein (ISG15) in peripheral blood mononuclear cells. Therefore, in the first experiment of the present study, we examined the relationship between the amount of IFN-tau injected into the uterus and the expression level of ISG15 in peripheral leukocyte of cattle. On 16-17 days post estrus, recombinant bovine IFN-tau produced by E. coli (0 [control], 500 or 1000 μg) was injected into ipsilateral uterine horns of 6 cattle per group. Blood samples were collected at every 2-4 hours until 24 hours post injection, peripheral leukocytes isolated by standard methods, and their ISG15 expression measured by real-time RT-PCR. ISG15 expression was stimulated by IFN-tau and peaked 4 hours after the initiation of treatment. Moreover, the expression level of ISG15 was positively correlated with the amount of IFN-tau injected into the uterus (R=0.86, p<0.01). Secondly, we examined IFN-tau secretion from conceptuses until the period of maternal recognition of pregnancy in cattle by measuring ISG15 expression in peripheral leukocyte. Blood samples were collected 7, 16, 18, 21 and 25 days post estrus, and ISG15 expression measured in peripheral leukocyte via real-time RT-PCR. AI (n=50) or ET (n=59) was performed on the day of estrus or 7 days later, respectively. In this experiment, non-pregnant cattle (AI: n=23, ET: n=30) were classified into 2 groups, in which cattle showed estrus with prolonged estrus cycle (greater than or equal to 25 days) and normal estrus cycle (<25 days). ISG15 expression increased and reached to the peak on day 21 in pregnant cattle. In non-pregnant cattle showing prolonged estrus cycle, the ISG15 expression was also increased, but the degree of the increase was smaller than that in pregnant cattle. On the other hand, in non-pregnant cattle showing normal estrus cycle, there was no significant increase of ISG15 expression during whole experiment period. In the period of maternal recognition of pregnancy, there was significant difference in ISG15 expression among 3 groups (p<0.05). These results demonstrated the direct relationship between the amount of IFN-tau secretion during the period of the maternal recognition of pregnancy and conception. In non-pregnant cattle showing normal estrus cycle, undetectable level of IFN-tau production during the period of maternal recognition of pregnancy indicated that the conceptuses might be already dead before this period. In non-pregnant cattle showing prolonged estrus cycle, the conceptuses were survived and produced enough IFN-tau to inhibit CL regression during the period of maternal recognition of pregnancy. However, in these cattle, the production of IFN-tau production was lower than pregnant cattle, suggesting that the growth of their conceptuses was deteriorated and consequently died beyond the period of maternal recognition of pregnancy. (poster)

Delayed Breeding Optimizes Conception in Dairy Cows with Prolonged Estrus

A common question of dairy farmers is whether to breed a cow that is still in estrus several hours after insemination. It is possible these cows have a longer interval between onset of estrus and ovulation time, and thus AM-PM rule is not valid. The objective of this study was to compare conception risk in cows with prolonged estrus bred once vs. twice (12 hours apart).

Comparison of estradiol and progesteron serum levels in ferrets suffering from hyperoestrogenism and ovarian neoplasia

The aim of this study was to determine whether serum levels of 17beta-estradiol and progesterone are significant diagnostic tools for the confirmation of specific reproductive diseases associated with hyperestrogenism. Thirty-one adult ferrets (&lt;i&gt;Mustela putorrius furo&lt;/i&gt;) were divided into five groups. The levels of serum 17beta-estradiol differed significantly when comparing females with ovarian tumors (817.80 ± 433.90 pmol/l) to intact (83.50 ± 32.53 pmol/l) and spayed, healthy females (73.17 ± 0.41 pmol/l) as well as to females with prolonged estrus (274.75 ± 192.40 pmol/l). Concentrations of serum progesterone differed significantly when comparing females with ovarian tumours (2.10 ± 1.85 ng/ml) to intact (0.40 ± 0.40 ng/ml) and spayed, healthy females (0.30 ± 0.12 ng/ml). Our study has made it clear that a determination of serum concentrations of 17-beta estradiol and progesterone is not sufficient for distinguishing between prolonged estrus and the presence of ovarian tumours. Therefore, it is advisable to employ other clinical procedures, such as ones allowing organ visualization. Increased concentrations of 17beta-estradiol in ferrets persisted for two weeks after hCG administration. This is particularly important in clinical practice, as negative effects of estrogens on bone marrow could persist for more than 14 days. Therefore, ferrets should be clinically monitored for a longer period of time.

The Type of Caloric Sweetener Added to Water Influences Weight Gain, Fat Mass, and Reproduction in Growing Sprague-Dawley Female Rats

Caloric sweetened beverages have been suggested to be a major dietary contributor to weight gain, particularly among adolescents. Dietary recommendations are for moderating intakes of added sugars; however, the question remains whether certain types of sugars should be limited. The objective of this study was to determine the effect of drinking different caloric sweetened beverages on the development of adiposity, metabolic, and endocrine disorders. Young (age 28 days) female Sprague-Dawley rats (n = 8-9 rats/group) were randomly assigned to drink either deionized distilled water (ddH2O) or ddH2O sweetened with 13% (w/v) glucose, sucrose, fructose or high fructose corn syrup 55 (HFCS-55) for 8 weeks. Rats drinking caloric sweetened solutions failed to completely compensate for liquid calories ingested by reducing their consumption of solid food. This resulted in greater total energy intake compared to the ddH2O control; however, there was no significant difference in total energy intake between rats drinking sucrose, fructose or HFCS-55. Of the different caloric sweeteners, only rats drinking HFCS-55 had greater (P < 0.05) final body weights and fat mass compared to the rats drinking ddH2O or glucose solution. This may have occurred because drinking HFCS-55 solution promoted a faster body weight gain. Adiposity induced by caloric sweetened water was not accompanied by metabolic disorders indicated by the absence of dyslipidemia and no differences in fasting serum glucose, insulin or C-peptide among the treatment groups. However, rats drinking HFCS-55 showed lengthened estrous cycles due to prolonged estrus. Based on this study, the type of caloric sweetener added to beverages should be considered when making dietary recommendation for reducing excess body weight and related health risk.

Factors underlying party size differences between chimpanzees and bonobos: a review and hypotheses for future study

Differences in party size and cohesiveness among females have been primary topics in socio-ecological comparisons of chimpanzees (Pan troglodytes) and bonobos (Pan paniscus). This paper aims to review previous studies that attempted to explain these differences and propose some hypotheses to be tested in future studies. Comparisons of recent data show that relative party size (expressed as a percentage of total group size) is significantly larger for bonobos than chimpanzees. Although the prolonged estrus of females, close association between mother and adult sons, female social relationships including unique homosexual behavior, and high female social status might be related to the increased party size and female cohesiveness of bonobos, these social and behavioral factors alone do not appear to explain the differences between the two species. Differences in ecological factors, including fruit-patch size, density of terrestrial herbs, and the availability of scattered foods that animals forage as they travel between large fruit patches could also contribute to the differences between chimpanzees and bonobos. However, these factors cannot fully account for the increased party size and female cohesiveness of bonobos. The higher female cohesiveness in bonobos may be explained by socio-ecological systems that reduce the cost in feeding efficiency incurred by attending mixed-sex parties. These systems may include female initiatives for party ranging movements as well as the factors mentioned above. Because of their geographical isolation, the two species probably evolved different social systems. Chimpanzees, whose habitats became very dry during some periods in the Pleistocene, likely evolved more flexible fission-fusion social systems to cope with seasonal and annual variation in food availability. On the other hand, bonobos had a large refugia forest in the middle of their range even during the driest periods in the Pleistocene. Therefore bonobos, whose habitats had more abundant food and smaller variation in food availability, probably evolved systems that help females stay in mixed parties without incurring large costs from contest and scramble competition.

Conference Lecture: Influence of stress on estrus, gametes and early embryo development in the sow

Systems with loose-housed sows have become common. Regrouping, which is commonly done after weaning and may coincide with many important reproductive events, causes stressful situations with elevated blood cortisol concentrations. Depending on group size, approximately 2–7 d are required for a new group of sows to become relatively stable. In a series of studies, the social stress after regrouping was simulated with repeated adrenocorticotrophic hormone (ACTH) treatments for approximately 48 h. Sows were allocated into control and experimental groups, fitted with jugular catheters, and blood samples were collected every 2 or 4 h. Follicular development and ovulation were monitored by transrectal ultrasonography every 4 h. Simulated stress during pro-estrus prolonged estrus and disturbed the follicular growth and ovulation. Giving ACTH during estrus elevated concentrations of cortisol and progesterone, and changed the intraluminal environment, including exaggerated amounts of mucus in the UTJ and isthmus. Although ACTH had no effect on the time of ovulation (relative to onset of standing estrus), or on embryo development, fewer oocytes/embryos were retrieved from the ACTH group than from the control group (51% vs. 81%, P < 0.05), and there was a tendency towards faster embryo transportation to the uterus. Short-term fasting after ovulation had an unfavourable effect on sperm numbers in UTJ/isthmus, cleavage rate of fertilized ova, as well as ova transport through the isthmic part of the oviduct. Treatment with ACTH after ovulation reduced numbers of spermatozoa at the zona pellucida and retarded cleavage rate of fertilized ova. Therefore, the timing of stress seemed to be an important factor regarding effects on reproductive events.

Advancement of reproductive senescence and changes in the early expression of estrogen, progesterone and µ-opioid receptors induced by neonatal hypoxia in the female rat

Perinatal hypoxia is a frequent birth complication, and although its early consequences on brain development have been well studied, few studies address any long-term effects. Postnatal insults producing small disturbances in endocrine function can have marked and long-lasting effects. In the present work we studied the effects of two types of perinatal brain injury: global hypoxia (H, 6.5% O 2 for 50 min) and hypoxia plus ischemia (HI, ligature of the right carotid artery) on female rat reproductive performance and expression of mediobasal hypothalamus-preoptic area (MBH-PO) estrogen, progesterone and µ-opioid receptors at different times after injury, measuring the mRNA (by semiquantitative RT-PCR) and protein (by Western blot). H or HI advanced approximately 3 months after the appearance of blunted preovulatory LH surges and cyclic irregularities (prolonged estrus) characteristic of the early stages of reproductive senescence. 48 h after H or HI we observed decreases in ERβ, µOR and PR (only in the H group) mRNAs and in total ER and µOR proteins, followed by increased PR levels (mRNA and protein) 7 days post-injury and by increased µOR protein and ERβ mRNA in the H group and ERα, ERβ and µOR mRNAs and ER protein in the HI group 30 days post-injury. Thus, an episode of hypoxia suffered during early postnatal life induces premature reproductive senescence on the female rats, accompanied by early changes in some MBH-PO hormone receptors (µOR, ER and PR), whose expression is intimately involved in the regulation of gonadotropin secretion and female sexual cyclicity.

Estrogenic activity of standardized extract of Angelica sinensis

Since ancient times, extracts of plants have been used for women's health to prevent menopausal symptoms. The symptoms of menopause have been attributed to a reduction in the amount of estrogen produced by the ovaries. In this study the estrogenic activity of a commercial standardized extract of the roots of Angelica sinensis, used to relieve climacteric symptoms was evaluated using in vivo tests such as the degree of cornification of vaginal epithelium, uterotrophic assays and serum LH concentration in ovariectomized rats. Furthermore, the effects on the estrous cycle in rat were investigated. The results obtained have shown that the administration of a standardized ethanol extract in ovariectomized rats exhibited a stimulation of the uterine histoarchitecture, a significant cornification in the vaginal epithelium and a reduction of serum LH concentration showing the estrogenic nature of the extract. Furthermore, the administration of the extract in intact female rats provoked a significant modification of the vaginal smear in 67% of treated rats. The estrous cycle thus modified was characterized by a prolonged estrus stage with a temporary reduction of the regular cyclicity.

Development of a prolonged estrus effect for use in Judas goats

The use of Judas goats (JGs; Capra hircus) to locate remnant animals is a powerful tool for enhancing feral goat eradication efforts, being especially important to island conservation programs. JGs are goats that are captured, fitted with radio telemetry collars and released. As goats are gregarious, JGs search out and associate with other goats. They can then be tracked down and any associated feral goats removed. JGs increase the efficiency of removing animals at low densities by reducing search time for hunters locating remnant herds. Prolonged duration or increased frequency of estrus in female JGs could potentially increase the efficiency of this method; does in estrus actively seek out and are searched for by bucks, and are more active than non-estrus does. Two experiments under controlled, farm conditions demonstrated that estrus can be prolonged by using Compudose-100 implants (one or two implants; single dose 21.1mg estradiol 17β) or a single Synovex-S implant (200mg progesterone and 20mg estradiol benzoate). Two Synovex-S implants failed to significantly prolong estrus. Single Compudose-100 implants provided the most dramatic effect, and when combined with 15mg PGF2∝ and sterilization by tubal occlusion provides an effective means of terminating pregnancy, inducing sterility and prolonging estrus 6–16-fold compared to sterile does and at least 82-fold compared to unaltered does, with a single intervention. Incorporating these methods into Judas goat programs will likely increase the efficiency and capability of feral goat control and island conservation.