Delayed uterine fluid clearance and reduced uterine perfusion in bitches with endometrial hyperplasia and clinical management with postmating antibiotic

In many species a transient uterine inflammatory response follows mating and is proposed to remove excess spermatozoa, bacteria, and other contaminants from the uterus. Similar events have been documented in the bitch involving increased uterine contractions, polymorphonuclear neutrophil influx and uterine artery vasodilation. Some healthy bitches with endometrial hyperplasia have increased numbers of uterine luminal polymorphonuclear neutrophils after mating and reduced fertility; it is purported that this represents a presumed postmating endometritis. This study used B-mode and Doppler ultrasonography at the time of mating to measure uterine contractions, clearance of ejaculated fluid, and uterine artery velocity in normal bitches and those with endometrial hyperplasia. Mating resulted in an increase in the number of uterine contractions, although fewer mating-induced contractions were noted in bitches with endometrial hyperplasia. Interestingly, uterine fluid cleared significantly more slowly after mating from the bitches with endometrial hyperplasia than the normal bitches (P = 0.01). In a further study, Doppler ultrasonography showed that in normal bitches there was a significant increase in uterine artery blood velocity (P = 0.04) and a decrease in the resistance index after mating (P = 0.04), indicating vasodilation. In bitches with endometrial hyperplasia the baseline resistance index was significantly higher than normal bitches (P = 0.05), and furthermore, although there was a significant decrease in resistance index after mating, in the bitches with endometrial hyperplasia this was of a smaller magnitude that in normal bitches. These findings indicate lower baseline uterine perfusion, and a blunted vasodilation response to mating in bitches with endometrial hyperplasia. Short-duration postmating administration of systemic antibiotic increased pregnancy rates in bitches with endometrial hyperplasia (P < 0.01). Litter sizes in bitches with endometrial hyperplasia were lower than those of normal bitches both before and after treatment with postmating antibiotic (P = 0.04 and < 0.01, respectively). Mating-induced endometritis in bitches with endometrial hyperplasia appears to affect fertility by reducing the uterine vasodilatory response to mating and delaying clearance of uterine fluid as a result of decreased uterine contractions but the effect can be ameliorated in part by the postmating administration of antibiotic.     

Changes in Ovaries and Uterus after Aglepristone Administration in the Third Week of Luteal Phase of Non-Pregnant Bitches

Objective

The mechanism of aglepristone action in the placentation time in the bitch remains unclear. The aim of this study was to describe the mechanism by which aglepristone influences ovaries and uterus and to measure the levels of steroid sex hormones in non-pregnant bitches.

Materials and Methods

Fourteen bitches assigned to a study (n=9) and control (n=5) group were given aglepristone and saline solution, respectively, on the 19th and 20th day after LH peak. On the 26th day after LH peak an ovariohysterectomy was performed. Blood samples were screened for estradiol and progesterone concentrations. Ovaries and uterine horns and bodies were isolated for histological and morphometrical diagnosis and immunohistochemistry analysis of α-estrogen and progesterone receptor expression.

Results

A decrease of progesterone (p<0.01) and no differences in total estrogen level in the study group were observed. There were no significant differences either in the histomorphometry or α-estrogen and progesterone receptors expression in ovaries. Increase in expression of progesterone receptors in endometrium without surface epithelium of horns (p<0.05), endometrial surface epithelium (p<0.05), myometrium of uterine body (p<0.01) and estrogen receptors in endometrium without surface epithelium of horns (p<0.05) was observed. Elevated estrogen receptors probably increased sensitivity of tissues to estrogens in the bloodstream and led to notable inflammation, haemorrhages, and hyperplasia in endometrium with mononuclear immune cell infiltration. The myometrium of horns and endometrium of uterine body of study bitches were significantly thicker than in the control group (p<0.05 and p<0.01). Furthermore myometrium of uterine body was thicker than myometrium of horns (p<0.001) and expression of progesterone receptors was higher in uterine body (p<0.01). No differences were observed between endometrium of horns and body within groups.

Conclusion

To the knowledge of the authors this is the first study, which describes the inflammatory effect developing in uterus in response to aglepristone administration, and attempts to elucidate its mechanisms.     

Hysterographic appearance and uterine histology at different stages of the reproductive cycle and after progestagen treatment in the domestic cat

The aims of this study were to characterize the hysterographic and histological features of the uteri and to perform immunohistochemistry with proliferating cell nuclear antigen (PCNA) in the cat endometrium at various stages of the reproductive cycle and after treatment with exogenous progestagen. Seventy-four female domestic cats submitted for routine ovariohysterectomy were categorized into six groups: inactive (n=20), follicular (n=9), luteal (n=18), and postpartum (n=12) stages of the reproductive cycle; cats given medroxyprogesterone acetate for estrus prevention (MPA group) (n=12); and cats with uterine pathological lesions (n=3). Hysterography was performed and the relation of the uterine and luminal shape in the hysterogram with the stage of the reproductive cycle as well as with any pathological conditions of the uterus was evaluated. The uteri and ovaries were thereafter surgically removed and sectioned for histological examination. The PCNA was used to demonstrate the expression of endometrial epithelial cell growth. The hysterographic appearance was found to differ between the six groups of cats. A straight uterine cavity was characteristic for cats in the inactive stage, whereas a wavy uterine cavity was characteristic for cats in the follicular stage. In the luteal stage, the luminal cavity of the uteri differed in shape with increasing progesterone concentration from straight to irregular wavy or coiled. The coil shaped uterine lumen seen in the MPA treated and pathological groups was considered also to be an expression of a progestagenic effect. Waviness and coiling of the uterine lumen was related to a proliferation of the endometrial glands, whereas irregular filling defects were indicative of endometrial cystic changes. This study is the first to demonstrate the expression of PCNA in the cat endometrium although no differences were found between the six groups of cats. The hysterographic appearance was found to differ according to stage of the reproductive cycle and pathological conditions. Thus, a normative hysterogram is now available for diagnosing the reproductive stage and uterine changes in cats developing endometrial hyperplasia with and without cystic changes.     

A model for cystic endometrial hyperplasia/pyometra complex in the bitch

The objective of this study was to develop a reliable model for the study of the cystic endometrial hyperplasia and pyometra complex (CEH/P) in the bitch. Greyhound bitches (n = 15) were ovariectomised and allocated into three groups (Group 1, n = 5; Group 2, n = 5; Group 3, n = 10, including 5 used from Group 1). Simulated proestrus, estrus and diestrus were induced by treatment with estradiol benzoate and megestrol acetate. The duration of cervical opening during estrus was determined by the intra-vaginal infusion of radio-opaque medium and subsequent radiography of the uterus (Group 1). One milliliter of a culture of Escherichia coli (with five uro-pathogenic virulence factors as identified by PCR: pap, sfa, hlyA, cnf1 and fim) was inoculated intra-vaginally daily throughout the simulated estrus (Group 2). One milliliter of the culture (n = 6) or sterile Luria-Bertani broth (n = 4) was introduced directly into the uterus on simulated diestrus Days 8 or 12 (Group 3). Necropsies were performed 12 and 7-14 days after the inoculation (Groups 2 and 3). The cervix remained open throughout the duration of simulated estrus (5-6 days) in four out of five bitches, and for a shorter duration (3 days of a 6-day estrus period) in one bitch (Group 1). CEH/P was induced by inoculation of bacteria into the uterus (10/10 bitches) but not into the vagina (0/5 bitches), (P = 0.003). A model for the study of CEH/P has been validated.     

Effect of undernutrition on the distribution of progesterone in the uterus of ewes during the luteal phase of the estrous cycle

The effect of undernutrition on ovarian and uterine venous progesterone concentrations and endometrial progesterone content on Days 5 and 10 of the estrous cycle were studied. Forty ewes were synchronized using progestagen pessaries. At pessary withdrawal, the ewes were fed diets to provide either 1.5 or 0.5 times the daily maintenance requirement (Group H, n = 20 and Group L, n = 20, respectively). Ewes fed the low nutrition diet (Group L) had higher mean peripheral progesterone concentrations than those fed the high plane diet (Group H; P < 0.05) but lower endometrial progesterone content on Day 5 (P < 0.05). Neither ovarian nor uterine venous levels were affected by nutrition on either Day 5 or 10. Progesterone concentrations in blood samples collected ipsilateral to ovaries bearing a corpus luteum (CL) were higher than in the contralateral samples (P < 0.001). It is concluded that undernutrition can produce a reduction of endometrial content of progesterone the first week after mating. Since no differences in ovarian venous concentrations were observed, it remains to be shown whether this variation is due to other variables, such as the population of endometrial progesterone receptors or other nonhormonal factors.     

Growth and microvascular development of the uterus during early pregnancy in ewes.

Growth and microvascular development of the uterus were evaluated for ewes on Days 12, 18, 24, and 30 after mating (3-4 ewes/day; Day 0 = day of mating) in two experiments. In experiment 1, fresh weight and dry weight of gravid uterine horns were increased on Days 24 and 30 after mating, whereas those of nongravid uterine horns were elevated only on Day 30. The increased fresh and dry weights of gravid uterine horns on Day 24 were associated with uterine hyperplasia (increased DNA content). Increased fresh and dry weights of gravid uterine horns on Day 30, however, were associated with hypertrophy (increased RNA:DNA and protein:DNA ratios) of uterine tissues. In experiment 2, vascularity of endometrial tissues was elevated on Days 24 and 30 after mating. In addition, dramatic changes in uterine architecture (increased lumenal diameter and decreased endometrial thickness) and in uterine microvascular development (increased abundance of large microvessels and development of a subepithelial capillary plexus) were observed by Day 24 after mating. Characterization of the patterns of uterine growth and microvascular development will enable us to further define the role of previously reported uterine and conceptus-derived growth and angiogenic factors during early pregnancy.     

Effects of ecbolic agents on measurements of uterine involution in the mare

Thirteen postparturient mares were used to investigate the effects of ecbolic agents on the rate of uterine involution. Mares were randomly assigned to one of three treatment groups: Group S = intravenous injection of 2 ml saline twice daily for 10 days post partum (n=4); Group O = intravenous injection of 20 units oxytocin twice daily for 10 days post partum (n=4); and Group P = intramuscular injection of 500 mcg fluprostenol twice daily for 10 days post partum (n=5). Ovulation was determined by daily transrectal ultrasonographic examination of the ovaries. On Days 6, 11 and 16 post partum, transrectal ultrasonography was used to measure cross-sectional diameters of the uterine body, uterine horns and fluid within the uterine lumen. Uteri were swabbed for aerobic bacteriologic culture on Days 11 and 16 post partum. Uterine biopsies were obtained from the base of the previously gravid uterine horn on Days 11 and 16 post partum for subjective assessment of endometritis and morphometric analysis of endometrial histoarchitecture. Mean values for all measurements of uterine involution did not differ among groups (P>0.05). For all mares, the diameter of luminal fluid was not correlated to diameter of the uterine body or uterine horns, or to morphometric measurements of endometrial histoarchitecture of the previously gravid uterine horn (P>0.05). Likewise, accumulation of fluid within the uterine lumen was not associated with endometritis or recovery of potential bacterial pathogens (P>0.05). Mean diameter of the previously gravid uterine horn was negatively correlated with morphometric measures of endometrial histoarchitecture of the previously gravid uterine horn (P<0.01).     

Differentiation between pyometra and cystic endometrial hyperplasia/mucometra in bitches by prostaglandin F2alpha metabolite analysis

Bitches with pyometra are potential emergency cases which may be clinically difficult to differentiate from cases of cystic endometrial hyperplasia (CEH) in combination with mucometra. In the present study plasma prostaglandin F(2alpha), as measured by its main metabolite 15-keto-13,14-dihydro-PGF(2alpha) (PG-metabolite) concentrations, blood biochemical and hematological parameters were measured in 59 bitches with pyometra, 10 bitches with CEH and nine controls to determine if PG-metabolite could differentiate between the three uterine conditions. Bitches with pyometra had significantly higher plasma levels of PG-metabolite than bitches with CEH (P=0.002) and the controls (P=0.002). PG-metabolite analysis alone had a high sensitivity (98.3%) and a high specificity (80.0%) for the differentiation of pyometra versus CEH in bitches where fluid in the uterus was diagnosed. When a combination of PG-metabolite and percentage band neutrophils (PBN) was used for differentiation of the two diagnoses, a sensitivity of 100% and specificity of 90.0% was obtained. This means that the combination of PG-metabolite and PBN analysis allows for differentiation between cases of pyometra and CEH. If the PG-metabolite level in a bitch is >or=4,524 pmol l(-1), there is a 99% probability of the diagnosis pyometra versus CEH. Levels of PG-metabolite >or=3,054 pmol l(-1), >or=2,388 pmol l(-1) or>or=1,666 pmol l(-1) indicates a 95%, 90% or 80% probability of pyometra, respectively. At high PG-metabolite levels (above about 3,000 pmol l(-1)), PG-metabolite alone is enough for differentiation of pyometra versus CEH. The results of the present study showed that PG-metabolite analysis is valuable in the diagnosis and prediction of severity of uterine diseases.     

Changes in sex hormone receptors during administration of progesterone to prevent estrus in the bitch

The development of lesions and the changes in sex hormone receptors were studied in the uteri of bitches under progesterone treatment. Twelve weeks after the onset of treatment, there was atrophy of the endometrium and increased thickness of the myometrium, without cystic dilatation of endometrial glands. This was accompanied by a dramatic reduction in estrogen-alpha and progesterone receptors in all cell types of the uterine wall. By 24 weeks after the onset of treatment, however, the endometrium was thickened due to the development of cysts of endometrial glands, while the myometrium thickness had returned to normal. The estrogen-alpha and progesterone receptors in most cell types of the uterine wall were again within the normal range. These results clarify and reconcile some apparent contradictions in the literature. They show that sex hormone receptors in most cell types of the uterine wall, especially endometrial gland cells and stromal cells, escape progestin (down) regulation after prolonged exogenous administration of progesterone.     

Uterine-specific proteins in luminal secretions of swine leukocyte antigen-inbred miniature swine with cystic endometrial hyperplasia

Uterine-specific proteins were evaluated in luminal secretions of Swine Leukocyte Antigen (SLA)-inbred miniature swine with cystic endometrial hyperplasia (CEH) by polyacrylamide gel electrophoresis (PAGE) and Sephacryl S-200 chromatography. CEH and non-CEH (NCEH) pigs (n = 23) were killed on Days 4, 9, and 15 of the estrous cycle (estrus = Day 0) and reproductive tracts were excised for collection of serum and uterine luminal protein. Uterine luminal protein was greater (p less than 0.05) on Day 9 than on Days 4 and 15 (42.9 vs. 6.1 and 29.4 mg, respectively) for CEH pigs and Days 4, 9, and 15 (8.5, 10.1, and 25.6 mg, respectively) for NCEH pigs. The presence of the uterine-specific acidic and basic proteins, as revealed by PAGE, was affected (p less than 0.025) by day of the cycle and CEH condition. All Day 15 NCEH pigs (4 of 4) produced the complete profile of these proteins, whereas none of the uterine protein samples representing other treatment groups contained them. Some minor acidic protein components were present in cystic fluids from CEH pigs, but these fluids lacked the typical uterine-specific proteins. PAGE analysis of Sephacryl S-200 fractions from uterine fluids of Day 15 NCEH pigs revealed the uterine-specific proteins in fractions IV (Mr 40,000) and V (Mr 15,000). The results of the investigation demonstrate an impairment in the secretion of uterine-specific proteins in cyclic SLA miniature swine with cystic endometrial hyperplasia.     

Interstrain inseminations and embryo transfers between the SLA miniature pig and standard crossbred pig

The purpose of this study was to determine fertilization and karyotypes of embryos after interstrain insemination and survival of embryos after reciprocal transfers between the National Institutes of Health SLA miniature pig and standard crossbred pig. Recovery of viable embryos indicated fertilization rates were not different in the two strains. Karyotypes of cells from embryos of both strains had the same chromosome number. The wide variation (within animal) in developmental stages of embryos recovered from the SLA minipig suggests the possibility of a prolonged ovulation interval, or a super imposed recruitment of a second set of follicles ovulating a few hours later. Cystic endometrial hyperplasia in the SLA minipig reduced the number of embryos recovered due to mechanical blockage of the uterine horns, thus preventing adequate flushing. SLA minipig recipients with no morphological evidence of cystic endometrial hyperplasia have a similar pregnancy rate to the standard pig. Cystic endometrial hyperplasia may contribute to reduced reproductive efficiency of the SLA minipig as a result of a detrimental effect on early embryo development and/or implantation.     

Lectin binding patterns in normal canine endometrium and in bitches with pyometra and cystic endometrial hyperplasia

Cystic endometrial hyperplasia (CEH) and pyometra in the bitch are dioestral syndromes, supposed to be caused by hormonal disturbances and changes in endometrial steroid hormone receptor levels. Histologically, the endometria show cystic dilated glands and, if bacteria succeed in invading the uterus, pyometra may develop in the following metoestrus. In this study, lectin histochemistry was performed on paraffin sections to compare carbohydrate expression of uterine glands and surface epithelium in healthy dogs and in dogs with CEH and pyometra. Lectin binding is a useful tool to identify glycoconjugates, especially of the glycocalyx, which has essential functions in the endometrium during reproduction. Uterine tissue was obtained from 18 healthy bitches in metoestrus or anoestrus and 18 bitches with a clinical diagnosis of CEH or pyometra. Normal endometria showed cycle-dependent changes in SBA, PNA, HPA and UEA binding during metoestrus and anoestrus. LCA did not show cycle-dependent changes and WGA bound to Golgi regions in the apical parts of surface epithelial cells only in metoestrous. Endometria with inflammatory alterations lost cycle-specific lectin binding patterns and, with increasing severity of pathological changes, showed a marked decrease in binding intensity to the glandular and surface epithelial glycocalyx and secretions. In dogs with CEH, unaltered glands with generally strong lectin binding to the glycocoalyx and Golgi regions were found adjacent to altered glands. The decrease of lectin binding in pyometra cases is supposed to be a result of glandular exhaustion after cystic hyperplasia. In addition, bacterial adhesion to sugar residues on the uterine surface epithelium might impede lectin binding.     

Repeated induction of abortion in bitches and the effect on plasma concentrations of relaxin, progesterone and estradiol-17beta

The aim of the present study was to investigate the effects of two medications on two subsequent abortions and plasma hormone concentrations of dogs. For this purpose, two groups of bitches (n=5 each), received the antiprogesterone aglepristone (Alizine) at 10mg/kg body weight on two subsequent days around day 30 after mating. In group II, the antiprolactin cabergoline (Galastop) was additionally administered po at 5 microg/kg body weight until the start of abortion. The plasma concentrations of relaxin, progesterone (P4) and estradiol-17beta (E2) were measured before, during and after each abortion. During the next cycle after the abortion, the same bitches were mated again and in pregnant animals, induction of abortion was performed as before. During the third cycle, pregnant bitches were allowed to whelp. Termination of first pregnancy occurred significantly earlier after the combined treatment (6.8 versus 10.6 days, p<0.05). In both groups and during both abortions, relaxin varied between individuals; however, there was a continuous decrease after the abortions and no significant differences between groups (p>0.05). In one bitch with high relaxin concentrations before treatment (11.6 ng/ml), a cystic endometrial hyperplasia was diagnosed. In the aglepristone only group, P4 concentrations increased significantly after the first application (p<0.05), then decreased continuously until day 45 after the beginning of abortion. In the combined group, there was a continuous decrease until day 45 (p>0.05). At this time, P4 concentrations between 0.47 and 84.9 nmol/l were measured in both groups. The level of E2 over time was not influenced by any medication. We therefore note that the two medications mainly influenced plasma concentrations of P4 in different ways, probably due to specific treatment-hormone interactions. However, all measurements fell within the range considered normal.     

Mucometra, cystic endometrial hyperplasia, and pyometra in the bitch: advances in treatment and assessment of future reproductive success

Pyometra is a common reproductive disorder which affects nearly one fourth of all female dogs before they reach 10 y of age. An association between pyometra and the most common uterine disease of the bitch, cystic endometrial hyperplasia, has been established, as the latter allows commensal bacteria originating from the vagina to proliferate in the uterus at the end of estrus. The progressive degenerative process in the development of cystic endometrial hyperplasia is usually proposed as the initiating lesion for pyometra in bitches; this is mediated by progesterone and potentially aggravated by estrogens. However, a separate process caused by local uterine irritation to trophoblastic reaction and bacterial proliferation has been recently proposed as an alternate mechanism leading to the development of pyometra. Pyometra is clinically distinct in pathogenesis, signs, treatment and prognosis from postpartum metritis or mucometra. Treatment of pyometra has historically involved ovariohysterectomy, however, during the last 10 y, numerous effective treatments have been proposed to treat both open and closed cervix pyometra with good success and future fertility. Among the treatments available, the use of repeated low doses of prostaglandins alone or in association with either dopamine agonists or progesterone-receptor antagonists has been demonstrated to be a viable alternative for valuable breeding dogs.     

Effect of cyproterone acetate,levonorgestrel and progesterone on adrenal glands and reproductive organs in the beagle bitch

Summary The effects of short-term (8 weeks) treatment with different doses of cyproterone acetate (CPA), levonorgestrel (LN) and progesterone (PRO) on the adrenal gland, ovary, uterus and vagina were studied in cycle-synchronised beagle bitches (first anoestrus). The same organs from non-treated primiparous beagle bitches at the 6th and 9th weeks of pregnancy were also included. In the animals treated with the highest doses of CPA (4.0 mg/kg/day orally) and PRO (42.5mg/kg/day subcutaneously), as well as in pregnant bitches (9th week of pregnancy), a decrease in adrenal weight and cortex width and also an apparent loss of cells in the zona fasciculata and zona reticularis were observed. A marked increase in ovarian weight was recorded only in pregnant bitches (6th week of pregnancy). This was reflected by the presence of multiple well-developed corpora lutea. The ovaries of virgin control and progestagen-treated bitches revealed ovarian atrophy. Progestagen treatment caused marked stimulation of the uterus, resulting in dose-related oedematous and hyperplastic changes. Comparable findings were also observed during pregnancy. The vaginal epithelium of the progestagen-treated and pregnant bitches showed marked mucification as compared with control bitches. These structural responses indicate that progestagen treatment stimulates a pseudopregnancy-like condition in the adrenal glands, uterus and vagina of the beagle bitch.Abbreviations for Hormones cited in this Paper ACTH Adrenocorticotropin - CRH Corticotropin Releasing Hormone - FSH Follicle Stimulating Hormone Beta Subunit - LH Luteinizing Hormone Beta Subunit - MSH Melanocyte Stimulating Hormone The author is grateful to Dr. Christel Schöbel and Mrs. P. Kurth for carrying out the experimental work on the animals, to Mrs. B. Schilk and Mrs. U. Tüshaus-Bußmann for their excellent technical assistance, and to Dr. P. Günzel for his advice and encouragement     

In vitro comparison of myometrial contractility induced by aglepristone-oxytocin and aglepristone-PGF2alpha combinations at different stages of the estrus cycle in the bitch

The aim of this in vitro study was to compare the uterokinetic activity of oxytocin and dinoprost, the natural PGF2α, with or without aglepristone, in canine myometrial fibers. Thirty-three bitches were allocated into one of four groups, depending on their estrous stage and whether or not they had received a treatment with aglepristone (metestrus aglepristone, n = 5; metestrus without treatment, n = 9; anestrus aglepristone, n = 9; anestrus without treatment, n = 10). After hysterectomy, longitudinal and circular uterine strips were mounted in organ baths. Oxytocin or PGF2α (10 nmol/l to 10 micromol/l) were applied non-cumulatively. A linear mixed effects models theory was used to compare the fiber effect, the aglepristone effect, and the treatment effect, from the area under the curves calculated from the contractile effect/concentration curves for each drug.Oxytocin and PGF2α induced concentration-dependent myometrial contractions in longitudinal (LF) and circular myometrial fibers (CF), indicating the presence of functional contractile oxytocin- and PGF2α-receptors in metestrus and anestrus.The contractile response to oxytocin was greater in LF than in CF in all of the groups; the response to PGF2α was greater in LF than in CF in non-treated bitches in anestrus and in treated bitches in metestrus. These results suggest that there is a difference in sensitivity or a heterogeneous distribution of oxytocin and PGF2α-receptors in the myometrial layers, which is independent of hormonal impregnation.The contractile response to oxytocin and PGF2α was significantly increased after aglepristone treatment in LF during metestrus, suggesting that the progesterone withdrawal induced by aglepristone has a role to play. The longitudinal myometrial layer also appeared to be the target for the two drugs at this stage.This study provides new information about canine uterine contractile activity, notably the differing behavior of myometrial CF and LF; in vivo studies are required to test the use of a combination of aglepristone and oxytocin in the treatment of canine pyometra.     

Estrus induction in Beagle bitches with the GnRH-agonist implant containing 4.7 mg Deslorelin

Estrogens, gonadotrophins, dopamine agonists, gonadotrophin releasing hormone (GnRH) and its agonists have been used for estrus induction in bitches. A long acting GnRH agonist implant (4.7 mg Deslorelin; Suprelorin®, Virbac) with a continuous hormone release has been developed for suppression of sexual function in male dogs. In this study we administered the Deslorelin implant placed subcutaneously on the medial side of the leg to induce estrus in 11 anestrous Beagle bitches (group A). 6 Beagle bitches (group B) with a spontaneous estrous cycle were used as controls. The progress of pre-estrus and estrus was documented by behaviour, vaginoscopy, vaginal cytology and progesterone concentration. In group A a bloody vaginal discharge was detected on average 4.8 (range 3-10) d after application of the implant. At this moment implants were removed under local anaesthesia. Pre-estrus lasted for an average of 4.5 d (range 1-12). All bitches showed estrous signs and ovulated. The ovulation took place on day 8.2 (range 4-15) after start of pre-estrus. In group B pre-estrus lasted for 7.5 d (range 6-9), and the mean day of ovulation was day 11 (range 9-13). As a consequence of ovulation, progesterone serum concentrations exceeded 10 ng/ml during or after the time of ovulation in all bitches. All bitches were bred to fertile Beagle stud dogs or inseminated with fresh semen intravaginally. Between days nine and 19 after ovulation all bitches underwent ovariohysterectomy. The uterine horns were flushed and flushes were examined for ova or embryos. The pregnancy rate in group A was 63.6% and in group B 66.7%. Despite the significantly shorter period of pre-estrus a fertile estrus could be induced in 7 out of 11 treated bitches. Induction of a fertile estrus can be achieved with a GnRH-implant—already registered for the use in male dogs—placed subcutaneously on the medial side of the leg.     

Effects of intrauterine foreign body on the localization of ( 3 H)-estradiol in rat uterine tissues, polymorphonuclear neutrophiles and eosinophiles

The effect of an intrauterine silk suture on localization of tritiated estradiol in the rat uterus was observed by dry autoradiography. 7 2.5 month old rats were ovariectomized and fitted with a 5-0 silk suture in one uterine horn. After 2 weeks, they were injected with 1 mcg estradiol 17-beta sc daily for 4 days, and 2 days later with .1 mcg per 100 gm body weight of 2,4,6,7-tritiated-estradiol-17-beta (specific activity 95 Ci per mM. Uteri from 6 rats were frozen-sectioned and mounted on dry emulsion-coated slides, at 10 and 60 minutes after sc injection, and 2 minutes after an iv injection in 1 rat. Autoradiograms observed 157 days later showed silver grains concentrated over nuclei in the outer layers of lumenal and glandular epithelium, substantia propria and muscularis in control horns. In uterine horns containing sutures, lesser radioactivity was observed in the basal epithelium and substantia propria, and higher activity in the nuclei of the stromal and glandular cells. No uptake was apparent in the eosinophiles or polymorphonuclear neutrophils which accumulated in the intrauterine suture horns.