Deslorelin Acetate Implants Research Articles

Physiological and behavioral effects of hormonal contraceptive treatment in captive, pair-bonded primates (Plecturocebus cupreus).

Hormonal contraception is an effective, reversible tool for managing birth rates in humans and nonhuman animals alike. However, manipulating reproductive hormones has behavioral consequences that can impact social and sexual behavior between conspecifics. First, we studied 18 pairs of nonreproductive titi monkeys (Plecturocebus cupreus) to test the efficacy of a novel method of hormonal contraception (deslorelin acetate implants) on reproductive hormone cycling in females and found significant reductions in urinary estrogens and progestagens among treated females compared to untreated controls. We then studied 35 nonreproductive pairs of coppery titi monkeys (Plecturocebus cupreus) to ascertain whether treating females with one of 2 different forms of hormonal contraception (deslorelin acetate implants (n = 17) or medroxyprogesterone acetate injections (n = 9)) would influence the relationship between pair mates compared to the relationship between untreated females and their vasectomized male mates (n = 9). Over a 5-month period, we found no differences in affiliative behaviors between pairs containing untreated females compared to pairs in which the female was treated with either deslorelin acetate or medroxyprogesterone acetate. Similarly, we found no differences in affiliation between pairs in the 2 treatment groups. This study is the first to examine behavioral consequences of hormonal contraception in a pair-bonding species. The results are encouraging for captive, managed breeding colonies of such social animals, especially those used in behavioral research.

Short-term clinical and hormonal effects of a deslorelin implant on late-prepubertal bitches – Based on flare-up signs

Gonadotropin-releasing hormone (GnRH) agonists offer an alternative to surgical sterilization in prepubertal dogs, preserving ovarian and uterine functions. However, the clinical and hormonal effects of GnRH agonist application during the late-prepubertal stage remain insufficiently understood. This study aimed to investigate the clinical effect (flare-up) and hormonal changes, specifically serum progesterone (P4) and estradiol (E2) levels, in bitches treated with 4.7 mg deslorelin acetate (DA) implants (Suprelorin®, Virbac, F) during the late prepubertal period. Sixteen clinically healthy kangal cross-breed bitches, aged 7–8 months, with a mean body weight of 20.5 ± 0.8 kg, were implanted with DA. Estrus signs were monitored daily, and blood and vaginal cytological samples were collected every other day for four weeks. Cytological changes were analyzed for overall and superficial cell index. Six out of sixteen DA-treated bitches (EST group; n = 6) exhibited clinical proestrus 8.6 ± 0.6 days after implant insertion. The mean serum concentrations of P4 and E2 at the onset of estrus were 1.38 ± 0.32 ng/ml and 37.38 ± 10.07 pg/ml, respectively. Notably, all non-estrus (N-EST group; n = 10) bitches demonstrated an increase in superficial cell index, in addition to expected cytological changes observed in the EST group. On the 18th day post-implantation, the EST group exhibited a significantly higher number of superficial cells compared to the N-EST group (p < 0.001). DA implantation resulted in cytological profile alterations accompanied by a slight increase in estrogen concentrations in all dogs. However, the flare-up response exhibited significant variability, differing from that observed in adult dogs. This study highlights the importance of meticulous timing and breed-specific considerations when utilizing DA for puberty manipulation in late-prepubertal bitches. The observed cytological and hormonal changes in response to DA implants provide valuable insights, but the variability in flare-up responses warrants further investigation.

Sustained-release deslorelin acetate implants disrupt oestrous cyclicity in the mare.

There is a need for a safe, effective and practical method of oestrus suppression in the mare. The aim of this study was to monitor ovarian activity in mares exposed to either 9.4 or 28.2 mg deslorelin acetate, a GnRH agonist, in the form of a sustained-release implant. Following oestrus synchronisation, mares were randomly assigned to one of three groups (n = 4 per group) and administered either one (Des1 group; 9.4 mg) or three (Des3 group; 28.2 mg) implants of deslorelin acetate (Suprelorin-12, Virbac Australia) or one blank implant (Control group; Virbac Australia). Mares underwent weekly blood sampling for 12 weeks following implant placement (Day 0-Day 84), with transrectal palpation and ultrasonography of the reproductive tract at all sampling timepoints except Days 56, 70 and 77. All mares showed baseline serum progesterone concentrations (SPC; ≤1.3 nmol/L or 0.4 ng/ml) on Day 0. Cycling Control mares showed typical oestrous cyclicity characterised by peaks and troughs in SPC over time. Four of eight treated mares demonstrated a sustained elevation in SPC after the initial ovulation after implant placement; SPC declined to baseline levels (Des1 group; 2 mares) or remained elevated (Des3 group; 2 mares) at the final sampling timepoint on Day 84. Oestrous cyclicity was erratic in three of the remaining four treated mares. In total, 87.5% (7 of 8) of treated mares showed atypical oestrous cyclicity after implant placement. These results suggest that deslorelin acetate disrupts oestrous cyclicity in the mare, which warrants further research.

EFFECTS OF A GNRH VACCINE AND DESLORELIN ACETATE IMPLANTS IN MALE FRESHWATER STINGRAYS (POTAMOTRYGON SP.).

Very little information is available in veterinary literature concerning chemical contraception in elasmobranchs. To decrease breeding and adverse reproductive behaviors, male Potamotrygon sp., housed in two zoologic institutions, were treated using methods used in other elasmobranchs. Four animals received deslorelin acetate implants (Suprelorin 4.7 mg and 9.4 mg), four animals received a gonadotropin-releasing hormone vaccine (Improvac 50-100 µg) twice separated by 1 mon, and two animals were not treated to serve as controls. Health checks, including blood sampling, coelomic ultrasound, and sperm analysis, were performed bimonthly and then monthly over almost 2 yr. Microscopic examination of sperm never revealed any significant change in concentration or motility. Size of testes and seminal vesicles glands did not change significantly after treatment. Plasma testosterone concentrations were stable (∼1 ng/ml) in intact and vaccinated animals throughout the study period. Plasma testosterone level increased significantly after deslorelin implantation and remained very high for at least 13 mon, never returning to initial values. Peak concentration varied according to the deslorelin acetate concentration used. Aggression toward females continued despite the use of contraception. Histopathologic examination on dead stingrays revealed active testicular tissue. These results suggest that deslorelin acetate implants and GnRH vaccine are ineffective at dosages used in our cases. Implants caused a continuous stimulation of the hypothalamic-pituitary-gonadal axis that could be harmful for the animals.

Efficacy and Safety of 4.7 mg Deslorelin Acetate Implants as a Neutering Option in Male Cats: A Large-Scale Multicentre Randomised Controlled Study.

This multicenter-controlled, double-masked randomized European study was conduc-ted to confirm both the efficacy and safety of a deslorelin implant in controlling fertility and sexual behavior in a large population of tom cats over a 12-month period. Among the 225 screened individuals, a total of 205 privately owned indoor intact male cats, aged 3 months of age or older, were randomly allocated to a deslorelin implant (n = 154) or to a negative control group (n = 51). After the screening visit performed between day (D)-14 and D-7, six additional visits were sche-duled on D0, D45, D93, D186, D279 and D372. Effects on testosterone, sexual behaviors, penile spines, testicular volume and intact male cat urine odor were assessed at every visit under masked conditions as regards to the treatment group. In addition, phone calls from the investigators to the owners were scheduled on D7 and then on a monthly basis whenever no visit was scheduled. Success was defined as an individual serum testosterone concentration below or equal to 0.10 ng/mL and was 77.9% at D45, 83.1% at D93, 84.4% at D186 and D279, and 61.7% at D372 in the deslorelin group, and 3.9% at D45, 5.9% at D93, 3.9% at D186, 7.8% at D279 and 3.9% at D372 in the negative control group. Testing for superiority was made stepwise from D45 to D372 upwards; the difference in success rates was significant from D45 to D372 (p < 0.001 for each time point). The mean testosterone concentration dropped from baseline in the deslorelin group, remaining below the set threshold of 0.1 ng/mL until D372. From D7 onwards, the mean sum score for sexual behaviors (including vocalization, urine marking, aggression and intact male cat urine odor) was significantly lower at each observation time point in the deslorelin group compared to the control group, where no decrease in scores was observed. The mean percent change to baseline of the testicular volume and the percentage of cats with a decreased visibility and adult appearance of penile spines were significantly lower in the deslorelin group as soon as D45. No relevant safety concerns were reported during the course of the study. The deslorelin implant Suprelorin® 4.7 mg (Virbac, Carros, France) is a safe and effective neutering option, inducing infertility over a 12-month period when administered to intact male cats aged between 3 months of age and 11 years of age. The implants also successfully reduced sexual behaviors (i.e., vocalization, urine marking, aggression), intact male cat urine odor, testicular volume and penile spine score for 1 year (372 ± 5 days).

Efficacy and Safety of 4.7 mg Deslorelin Acetate Implants in Suppressing Oestrus Cycle in Prepubertal Female Dogs.

Our multicentric, masked, controlled and randomised study aimed to assess the efficacy and safety of Suprelorin® 4.7 mg (Virbac, Carros, France) regarding oestrus prevention in prepubertal intact bitches. Twelve- to eighteen-week-old females (n = 83) were allocated either a deslorelin implant (n = 62) or 0.9% sodium chloride (n = 21) group. Clinical assessment (heat signs), 17β oestradiol and progesterone assays, and vaginal cytology were performed at day (D)0, D7, D21, month (M)3 and M6 after product administration, and were then performed every other month until reaching puberty. Trained owners assessed heat signs between each veterinary visit. All bitches (n = 83) reached puberty before M30. Deslorelin significantly extended the median time to sexual maturity when compared to the control group (377 days versus 217 days after D0, p &lt; 0.0001). Three females, implanted between 16 and 18 weeks of age, expressed an induced oestrus. Additional descriptive data, collected over a 24 month-period, showed functional reproductive abilities in both deslorelin (n = 52) and control (n = 21) groups once puberty was achieved. In conclusion, Suprelorin® 4.7 mg seems to be an effective and safe option for postponing the onset of oestrus when administered to prepubertal female dogs aged from 12 to 16 weeks.

In ferrets with hyperadrenocorticism, does use of deslorelin acetate implants compared to adrenalectomy result in a superior prognosis?

PICO question&#x0D; In ferrets with hyperadrenocorticism, does use of deslorelin acetate implants compared to adrenalectomy result in a superior prognosis?&#x0D; &#x0D; Clinical bottom line&#x0D; Category of research question&#x0D; Treatment&#x0D; The number and type of study designs reviewed&#x0D; One study was reviewed, a retrospective cohort study that directly compared the outcomes of these treatments&#x0D; Strength of evidence&#x0D; Weak&#x0D; Outcomes reported&#x0D; The study found that in ferrets with hyperadrenocorticism, use of deslorelin acetate implants resulted in a longer average time to recurrence of clinical signs and a lower mortality rate than adrenalectomy. However, the strength of evidence for this study is weak and it has several design limitations&#x0D; Conclusion&#x0D; In view of the evidence, both deslorelin acetate implants and adrenalectomy are valid treatments for a ferret with hyperadrenocorticism, but it cannot be concluded based on the current literature that deslorelin acetate implants result in a superior prognosis&#x0D; &#x0D; How to apply this evidence in practice&#x0D; The application of evidence into practice should take into account multiple factors, not limited to: individual clinical expertise, patient’s circumstances and owners’ values, country, location or clinic where you work, the individual case in front of you, the availability of therapies and resources.&#x0D; Knowledge Summaries are a resource to help reinforce or inform decision making. They do not override the responsibility or judgement of the practitioner to do what is best for the animal in their care.&#x0D; &#x0D;

Long-term effect of repeated deslorelin acetate treatment in bitches for reproduction control

Long-acting gonadotropin-releasing hormone (GnRH) analogs, which are approved for male dogs and ferrets, have been used off-label to suppress estrus in bitches predisposed to the side effects of spaying. Health data from the past 12 years were evaluated from bitches without progestogen pretreatment that received deslorelin acetate (DA) to suppress estrus for the first time before the age of 4.5 years. The study population included 32 client-owned bitches repeatedly treated with either 4.7 mg or 9.4 mg DA implants for a period of 5.3 ± 3.4 years (range 0.5–11.3 years). Follow-up information concerning immediate side effects of DA occurring within five months after the first DA treatment (n = 23) as well as long-term side effects of sustained gonadal suppression occurring after five months up to three years (n = 2), three years up to five years (n = 2) or more than five years (n = 8) were assessed through a questionnaire. Treatment was considered successful if no major side effects requiring medical treatment occurred, which applied to 26 out of 32 (81 %) bitches. In the six remaining bitches, the following major side effects led to treatment discontinuation: persistent urinary incontinence (n = 1), reoccurring induced heat (n = 1), uterine disease (n = 3) and/or ovarian tumor (n = 3). The bitches recovered completely after surgical spaying and/or DA implant removal. Minor side effects that did not require therapy or affect animal welfare included body weight changes (n = 18), subtle behavioral changes (n = 13), induced heat (n = 12), coat changes (n = 11), pseudocyesis (n = 6), transient urinary incontinence (n = 4), and/or temporary thickening of the uterine wall with little anechogenic content (n = 2). To examine a possible causal relationship between adverse side effects and DA treatment, further studies should compare the frequency of pathologies between groups of GnRH-treated, intact and spayed bitches of similar breeds and ages. Nevertheless, DA application before the age of 4.5 years may be a means of postponing surgical spaying for several years in breeds at high risk for developing urinary incontinence. Before DA is used in bitches, owners should be fully informed regarding possible side effects.

The past, present and future of hormonal contraceptive use in managed captive female tiger populations with a focus on the current use of deslorelin acetate.

Tigers (Panthera tigris spp.) are endangered in the wild; ensuring sustainable insurance populations requires careful planning within zoological collections. In captive situations, contraceptives are often used to control breeding and ensure genetically viable populations that contain manageable numbers of animals; reversible contraceptives are ideal because they offer flexibility for breeding management. Historically, synthetic progestins, such as melengestrol acetate implants, were used in female tigers, but these are associated with an increased risk of reproductive pathology and subsequent infertility. Recent management advice to ex-situ collections has been to transition to the use of gonadotropin-releasing hormone agonists, such as deslorelin acetate implants, which do not appear to have a similar risk of reproductive pathology but are associated with highly variable reversal times in exotic felids. Using data from 917 contraceptive records in female tigers captured by the Association of Zoos and Aquariums Reproductive Management Center and the European Association of Zoos and Aquaria Reproductive Management Group's joint Contraception Database and from supplementary surveys, this study reviews the changing use of contraceptives in captive female tigers. The aim was to describe the historical and current use of contraceptives and provide a comprehensive assessment on the use of deslorelin implants, including data on product protocols, efficacy, pathology, and reversibility. This study determined that current dose, frequency, reversibility, and anatomical placement sites of deslorelin implants are highly variable, indicating that specific, readily available, unified, evidence-based recommendations on the use of deslorelin would be useful for future contraceptive use in managed tiger populations.

Determination of Efficacy of Single and Double 4.7 mg Deslorelin Acetate Implant on the Reproductive Activity of Female Pond Sliders (Trachemys scripta)

Simple SummaryNorth American pond sliders (Trachemys scripta) are invasive alien species that, following the release of pet specimens in the wild over the decades, have established breeding populations outside their native habitat, with detrimental effects on local biodiversity. Their commerce and breeding have been recently banned in the European Union, and national programs are being introduced by Union Members to eradicate and control their presence. Among other means of population control, the use of long-acting drugs for chemically induced infertility could be a promising tool to prevent the reproduction of these animals. Efficacy of single and double intramuscular deslorelin acetate implants was investigated during a one-season follow-up: plasmatic sexual hormones concentration and morphometric evaluation of ovarian activity by computed tomography were performed about every 30 days to detect the differences between the control group (no implant), single-implant group, and double-implant group. Results show no inhibition of reproductive activity for the ongoing reproductive season, but suggest possible infertility starting from the following season.The use of long-acting gonadotropin-releasing hormone (GnRH) agonists to suppress fertility has been poorly investigated in reptiles, and the few available studies show inconsistent results. The efficacy of single and double intramuscular 4.7 mg deslorelin acetate implants in captive pond sliders (Trachemys scripta) was investigated, with 20 animals divided into three groups: a single-implant group (6 animals), a double-implant group (6 animals), and a control group (no implant). During one reproductive season (March to October), plasmatic concentration of sexual hormones (estradiol, progesterone, and testosterone) and ovarian morphometric activity via computed tomography were monitored about every 30 days. A significative decrease in the number of phase II ovarian follicles was detected in the double-implant group compared with the control group, but no significant difference was noted in the number of phase III and phase IV follicles, egg production, and plasmatic concentration of sexual hormones. Results show that neither a single nor a double deslorelin acetate implant can successfully inhibit reproduction in female pond sliders during the ongoing season, but the lower number of phase II follicles in the double-implant group can possibly be associated with reduced fertility in the following seasons.

Effect of a GnRH agonist (deslorelin) on ovarian activity in leopard geckos (Eublepharis macularius)

The aim of this study was to evaluate the effectiveness of deslorelin acetate in the regulation of reproductive activity in captive leopard geckos (Eublepharis macularius). Fourteen healthy adult females were separated into two groups. Under general anaesthesia, deslorelin acetate implants (4.7 mg) or placebo implants were administered into the coelom of ten female geckos and four female geckos, respectively. One healthy adult male Leopard gecko was added to each group of females (five females with GnRH implants and two females with placebo implants). The geckos were regularly monitored over two breeding seasons (visual examination, weight control). Nesting sites were checked daily. There were no postoperative complications or any other health problems during the study. Implant administration did not result in long-term suppression of reproductive function. No significant differences were found in the number of clutches between the female groups (deslorelin implants versus placebo implants) or in the number of clutches between the two breeding seasons. Deslorelin acetate implants did not interfere with ovarian activity in captive female leopard geckos. The use of GnRH agonist implants is not an appropriate method for control of reproductive function in female leopard geckos.

ASSESSING THE EFFICACY OF DESLORELIN ACETATE IMPLANTS (SUPRELORIN) IN ALTERNATIVE PLACEMENT SITES.

Hormonal contraception is being increasingly used to manage captive animals in zoological collections. Many of the animals placed on contraception are of genetic importance within captive breeding programs; therefore, it is imperative that the application of contraceptive products minimize potential side effects and facilitate a return to fertility if required. Deslorelin acetate implants (Suprelorin®) are one example of a hormonal contraceptive that is frequently used in captivity as they are easy to use and effective in most species. It is hypothesized that removing implants may hasten reversal of contraception treatment; therefore, placement in a location where they can easily be recovered is advocated. In this report, the efficacy and safety of Suprelorin implants placed in their recommended site between the scapulae is compared with alternative placement sites where implants can more easily be located for removal. Using the European Association of Zoos and Aquariums (EAZA) Group on Zoo Animal Contraception (EGZAC) Contraception Database, rates of success, failure, and reversal in 561 records of Suprelorin use in European collections are compared. Of these, 357 have information relating to the location of implant placement. When correctly applied, rates of efficacy were high (>99%) irrespective of placement site. Rates of reversal were 33.3% higher in alternative placement sites, although in most cases it is unknown whether implants were removed or not. In conclusion, the placement of Suprelorin implants in alternative sites does not negatively affect the efficacy, facilitating at the same time implant removal, minimizing potential side effects, and reducing reversal time, allowing for effective use in captive conservation breeding programs.

Evaluation of the effects of a 4.7-mg deslorelin acetate implant on egg laying in cockatiels (Nymphicus hollandicus).

OBJECTIVE To evaluate effects of administration of a 4.7-mg deslorelin acetate implant on egg laying in healthy cockatiels (Nymphicus hollandicus). ANIMALS 52 cockatiels. PROCEDURES 26 breeding pairs (a female and its respective male in each pair) were selected on the basis of their history of egg laying. Female birds were sedated and received a 4.7-mg deslorelin acetate implant (n = 13) or placebo implant (13) in the subcutaneous tissues between the scapulae. Male and female birds of each breeding pair were placed in separate but adjacent cages. Birds were exposed to 16 hours of light and 8 hours of darkness. A nest box was placed in cages of female birds to stimulate reproductive activity. Egg production and quality were monitored daily for 365 days. RESULTS Deslorelin acetate implants significantly suppressed egg laying in cockatiels, compared with effects for the placebo implants. Eleven of 13 placeboimplanted birds laid eggs between 12 and 42 days after implantation. None of the deslorelin-implanted birds laid eggs within 180 days after implantation, and only 5 of 13 deslorelin-implanted birds laid an egg during the study period (first egg laid between 192 and 230 days after implantation). No differences in egg quality or number of eggs per clutch were observed between the 2 groups. CONCLUSIONS AND CLINICAL RELEVANCE Insertion of a 4.7-mg deslorelin acetate implant suppressed egg laying in healthy cockatiels for at least 180 days. Studies are necessary to evaluate effects of a deslorelin acetate implant in other avian species or in association with reproductive disorders.

Use of deslorelin implants for contraception in slender tailed meerkats (Suricata suricatta)

Deslorelin acetate implants are advocated for contraception in many mammalian species, including meerkats (Suricata suricatta), but little objective data exists on efficacy of this method. This study followed two groups...

COMPARISON OF TWO 4.7-MILLIGRAM TO ONE 9.4-MILLIGRAM DESLORELIN ACETATE IMPLANTS ON EGG PRODUCTION AND PLASMA PROGESTERONE CONCENTRATIONS IN JAPANESE QUAIL (COTURNIX COTURNIX JAPONICA)

Reproductive disease in captive avian species is common, and medical management is often chosen over surgical removal of the reproductive tract. In a previous study with Japanese quail, a single 4.7-mg deslorelin acetate implant reversibly decreased egg production in 6 out 10 birds for 70 days. The objective of the current study was to evaluate the effects of two 4.7-mg deslorelin acetate implants versus one 9.4-mg implant on egg production and plasma progesterone concentrations in Japanese quail ( Coturnix coturnix japonica). Following a 10-day period of consistent egg laying, 30 adult female Japanese quail were anesthetized and received two 4.7-mg deslorelin implants (n = 10), one 9.4-mg deslorelin implant (n = 10), or a single, identical placebo implant (n = 10) s.c. between the scapulae. Egg production was monitored daily, and plasma progesterone concentrations were measured on days 0, 14, 29, 120, 148, and 182 via enzyme-linked immunoassay. All birds were weighed periodically and euthanized at day 182, after which their reproductive tracts were evaluated at gross necropsy. Seven out of 10 birds treated with two 4.7-mg implants ceased egg laying 1 wk after implantation and remained nonovulatory for approximately 100 days. Cessation of egg laying for the 9.4-mg treatment group occurred in 7 out of 10 birds; onset was variable (weeks 5-12) and continued for the remainder of the study period. Plasma progesterone concentrations for deslorelin treatment groups were not significantly different compared to the placebo group at any time point. In conclusion, the two 4.7-mg and the one 9.4-mg implant treatments ceased egg laying in a similar number of birds, but the 9.4-mg implant had a slower onset of action and the effects on egg laying were inconsistent throughout the study period. Further studies evaluating use of deslorelin acetate in other avian species are needed.

Fertility in Adult Bitches Previously Treated with a 4.7 mg Subcutaneous Deslorelin Implant.

The absence of fertility problems in male dogs after a single treatment with deslorelin acetate (Suprelorin(®)) is well acknowledged. However, reports on the application of deslorelin in the bitch and information concerning fertility after implant treatment are still limited. In this retrospective study, data concerning induced and spontaneous oestruses of 39 bitches from 17 breeds, treated with deslorelin acetate implants (4.7 mg Suprelorin(®), Virbac, France), were retrieved to assess post-treatment fertility (ovulation rate, pregnancy rate and litter size). Animals were grouped according to treatment characteristics: group 1 (Gr1) - females submitted to oestrus induction, showing natural oestruses afterwards (n = 19); group 2 (Gr2) - females re-implanted with 4.7 mg deslorelin acetate to re-induce oestrus, showing subsequent spontaneous post-implant oestruses (n = 7); and group 3 (Gr3) - females submitted to a 4.7 mg deslorelin acetate implant for oestrus suppression, evaluated at subsequent spontaneous post-implant oestruses (n = 13). Comparison of fertility traits between induced and post-treatment spontaneous oestruses in Gr1 and Gr2 (short treatments), or between spontaneous oestruses after long-treatment schedules (Gr 3) revealed a slightly better performance in spontaneous cycles compared with induced cycles: ovulation rate post-treatment was 97.1%, 94.1% and 94.4% and the pregnancy rate post-treatment was 91.2%, 88.9% and 84.6% for groups 1, 2 and 3, respectively. Nevertheless, fertility in induced and post-treatment oestruses was considered normal. Moreover, the individual litter size did not differ within groups between induced and spontaneous cycles. From these findings, we concluded that treatment with 4.7 mg deslorelin implants did not compromise the bitches' fertility in subsequent oestruses.

The effect of deslorelin acetate on the oestrous cycle of female guinea pigs

Deslorelin acetate, a GnRH agonist, is commonly used to prevent folliculogenesis in several species. However, little is known of the effect of deslorelin acetate implants on the oestrous cycle of female guinea pigs. Fifteen intact healthy female guinea pigs were investigated in this study. Signs of sexual behaviour, the presence of a vaginal membrane along with plasma concentrations of oestradiol (E 2 ) and progesterone (P 4 ), were monitored during two consecutive oestrous cycles. At the beginning of the third oestrous cycle each guinea pig was administered an implant of the GnRH analogue, deslorelin acetate, (4.7 mg). When compared to the untreated state, deslorelin implantation was associated with altered signs of oestrus. The average time to opening of the vaginal membrane was delayed. After opening, the vaginas were found to be variably opened and closed. A significant reduction in P 4 (to less than 1.0 ng/ml) and cessation of P 4 cyclical variation was observed. Plasma E 2 remained high during the whole experimental period. This study shows that cessation of the oestrous cycle by the deslorelin implant might be useful in preventing pregnancy in guinea pigs.

Deslorelin Implants in Pre‐pubertal Female Dogs: Short‐ and Long‐Term Effects on the Genital Tract

Deslorelin acetate is a GnRH agonist used for contraception in dogs. This study aimed to evaluate the treatment of pre-pubertal female dogs with deslorelin acetate implants, to better investigate the primary stimulatory effect of the drug and the long-term effects on the genital tract, throughout repeated treatments. Sicilian hound female dogs (24) were randomly assigned to treated group, control group 1 and control group 2. First group bitches were implanted at 4.5, 9.0 and 13.5 months and monitored clinically, ultrasonographically and endocrinologically, throughout the study period (13.5 months). Control group 1 bitches were not implanted and clinically monitored for the same period. At 18 months, the animals underwent ovariohysterectomy, thus allowing evaluation of the internal genitalia. Control group 2 bitches were ovariohysterectomized at the age of 4.5 months. The suppression of oestrus was obtained in the treated group despite the fact that the first implant caused a modest increase in plasmatic levels of 17-beta estradiol and an evident cornification of the vaginal mucosa cells (50-80%). Estradiol and progesterone were at baseline levels for the remaining study period, in which no other oestrous manifestations were observed. The external genitalia maintained a juvenile appearance. The ovaries, ultrasonographically, showed no follicular structures and stayed the same size. At 18 months, the genital tract was still juvenile with inactive small ovaries and a thin filiform uterus. Deslorelin suppressed ovarian activity in pre-pubertal bitches, and oestrous induction was not observed despite the presence of the primary stimulatory effect of the drug. Juvenile genitalia were an expected side effect of the treatment.

Evaluation of the efficacy and safety of single administration of 4.7-mg deslorelin acetate implants on egg production and plasma sex hormones in Japanese quail (Coturnix coturnix japonica)

"Evaluation of the efficacy and safety of single administration of 4.7-mg deslorelin acetate implants on egg production and plasma sex hormones in Japanese quail (Coturnix coturnix japonica)" published on 01 Mar 2013 by American Veterinary Medical Association.

Evaluation of the efficacy and safety of single administration of 4.7-mg deslorelin acetate implants on egg production and plasma sex hormones in Japanese quail (Coturnix coturnix japonica)

To evaluate the effects of 4.7-mg deslorelin acetate implants on egg production and plasma concentrations of 17β-estradiol and androstenedione in Japanese quail (Coturnix coturnix japonica) over 180 days and assess safety of the implants in quail via gross and histologic examination. 20 female Japanese quail. Following a 7-day period of consistent egg laying, quail were anesthetized and received a 4.7-mg deslorelin implant (treatment group; n = 10) or identical placebo implant (control group; 10) SC between the scapulae. Egg production was monitored daily. Plasma concentrations of 17β-estradiol and androstenedione were measured on days 0 (immediately prior to implant injection), 14, 29, 62, 90, 120, 150, and 180 via radioimmunoassay. Birds were weighed periodically and euthanized at day 180 for complete necropsy. Egg production was significantly decreased in the treatment group, compared with the control group, from 2 to 12 weeks after implant injection. Egg production ceased in 6 of 10 quail in the treatment group (mean duration of cessation, 70 days). Plasma androstenedione and 17β -estradiol concentrations were significantly lower on day 29 in the treatment group than in the control group. On day 180, 17β -estradiol concentration was lower in control than in treated birds.No clinically relevant lesions were detected in either group at necropsy [corrected]. 4.7-mg deslorelin acetate implants reversibly decreased egg laying for approximately 70 days in most of the Japanese quail evaluated. Further studies evaluating implants containing different concentrations of the drug are needed in quail and other avian species.