Ovulation after sympathetic denervation of the rat ovary produced by freezing its nerve supply

The ovaries of cyclic female rats were unilaterally or bilaterally denervated or sham-operated. Denervation was achieved by freezing the ovarian vascular pedicle and suspensory ligament about 1 cm from the ovary; this technique renders the ovary devoid of innervation for up to 10 days. Denervated ovaries from 6 unilaterally and 7 bilaterally operated animals exhibited normal ovulation rates (5.8 +/- 1.0 and 5.2 +/- 1.2 respectively, mean +/- s.e.m.) compared with intact (5.6 +/- 0.4) and sham-operated controls (4.4 +/- 0.6 unilaterally sham-operated; 4.1 +/- 0.8 bilaterally sham-operated). It is concluded that the mechanism of follicular rupture is unaffected by the absence of ovarian sympathetic innervation.     

Effect of unilateral ovariectomy on compensatory ovarian hypertrophy, peripheral concentrations of follicle-stimulating hormone and luteinizing hormone, and ovarian venous concentrations of estradiol-17 beta in prepuberal gilts

A study was designed to characterize the compensatory ovarian response to unilateral ovariectomy (ULO) in prepuberal gilts and to investigate further the mechanisms involved in compensatory ovarian hypertrophy (COH). Forty-eight crossbred gilts were sham ovariectomized (Sham) or unilaterally ovariectomized at 130 days of age (Day 0). Remaining ovaries in ULO gilts were removed and Sham gilts were bilaterally ovariectomized 2, 4 or 8 days later. A peripheral blood sample was taken before surgery and ovarian venous blood samples were taken before removal of each ovary. Serum estradiol-17 beta (E2) concentrations were determined. Mean wet and dry ovarian weights per ovary on Day 2 for ULO and Sham gilts were 3.4 versus 2.8 and 0.26 versus 0.24 g, respectively. Those weights on Days 4 and 8 were greater (P less than 0.01) for ULO than Sham gilts. Follicular fluid weight per ovary was greater (P less than 0.05) for ULO than Sham gilts on Days 2, 4 and 8. Ovarian venous E2 concentrations were greater (P less than 0.01) for ULO than for Sham gilts on Days 2 and 4 but were similar on Day 8. In a second experiment, 42 prepuberal gilts 130 days of-age were subjected to Sham (n = 18), ULO (n = 18) or bilateral ovariectomy (BLO; n = 6) to evaluate follicle-stimulating hormone (FSH) and luteinizing hormone (LH) secretion immediately after surgical treatment. Release of FSH within the first 24 h was greater for BLO than ULO and for ULO than Sham gilts.(ABSTRACT TRUNCATED AT 250 WORDS)     

The fate of embryos transferred to the oviducts of entire, unilaterally ovariectomized and bilaterally ovariectomized ewes

Embryos collected from donor ewes 2 days after oestrus were transferred to the oviducts of entire cyclic (Group EC), unilaterally ovariectomized and cyclic (Group UO), entire anoestrous (Group EA), and bilaterally ovariectomized (Group BO) ewes, and 4 h, 1, 3 or 5 days after transfer the oviducts and uteri were flushed to recover embryos. Ewes in Group BO were untreated or treated with regimens of progesterone and oestradiol designed to simulate ovarian secretion before, around the time of, and after oestrus in entire ewes. There were no differences in the proportions of transferred embryos that were recovered, or in their location (oviduct or uterus), between the two sides of Group UO ewes and they were similar to recovery rates and locations of embryos in Group EC ewes. At 3 days after transfer, 62% and 50%, respectively, of embryos recovered from ewes in Groups EC and UO were in the uterus and by 5 days the percentages had risen to 89% and 75%, respectively. With all treatment regimens fewer of the transferred embryos were recovered from Group BO ewes than from Group EC ewes and few were located in the uterus. In Group BO ewes low recovery rates, and failure of embryos to enter the uterus, appeared to be due to deficiencies in the treatment regimens rather than to effects of ovariectomy. Most embryos recovered from treated ewes in Group BO and those in Groups EC and UO showed apparently normal development (86% and 79%, respectively), while 65% and 75%, respectively, recovered from untreated Group BO and Group EA ewes had developed normally. Only 9 of 163 embryos recovered from the untreated Group BO and EA ewes were located in the uterus and 8 of the 9 had failed to develop normally. Clearly, the steroid hormone requirements for development in the oviducts are not critical, but this is not so for the uterus.     

Counteraction of testosterone-induced suppression of the pituitary-ovarian axis in rats by flutamide.

Daily administration of 100 micrograms of testosterone to unilaterally ovariectomized rats for 18 days caused a significant decrease in compensatory ovarian hypertrophy. The number of corpora lutea was markedly reduced and many cystic follicles were noticeable. Administration of graded doses (0.5, 1 and 3 mg daily) of flutamide over the same period did not cause any significant change in the weight and histology of the ovary in untreated unilaterally ovariectomized animals. However, treatment with the same doses of flutamide prevented the changes observed in the reamining ovary of testosterone-treated animals.     

Gamma-aminobutyric acid in the genital tract of the rat during the oestrous cycle

The highest values of gamma-aminobutyric acid (GABA) in the genital tract of the rat at different stages of the oestrous cycle were found in the oviduct (3.5-7 micrograms/mg protein) and the lowest in the ovary (50-100 ng/mg protein). The values for uterus and vagina ranged between 80 and 150 ng/mg protein. GABA (10-30 ng/microliter) was also found in fluid in the ovarian bursa. At 11:00 h, on the day of oestrus, GABA content increased in the ovaries but values in the oviducts were maximal at 11:00 h on the day of pro-oestrus. Variations in GABA content of the vagina were also found. Uterine cervix or uterine horn showed no changes during the oestrous cycle. The GABA content was not uniform throughout the oviduct: the highest values were found in the portion next to the ovary. At 10 days after removal of the right oviduct, GABA values in the ovary and ovarian bursa fluid decreased on the operated side. At 1 month after surgery, the values in ovary were normal but the values in ovarian bursa fluid were still low, suggesting that the source of ovarian GABA was not the oviduct. The variations observed in the present paper suggest an involvement of GABA in reproductive physiology.     

Bacterial colonization of the ovarian bursa in dogs with clinically suspected pyometra and in controls

Septic peritonitis occurs relatively commonly in dogs. Secondary septic peritonitis is usually associated with perforation of intestines or infected viscera, such as the uterus in pyometra cases. The aim of this study was to evaluate the bacterial flora in the ovarian bursae of intact bitches as a potential source of contamination. One hundred forty dogs, clinically suspected of pyometra, were prospectively enrolled. The control group consisted of 26 dogs that underwent elective ovariohysterectomies and 18 dogs with mammary gland tumors that were neutered at the time of mastectomy. Bacteriology samples were taken aseptically at the time of surgery from the bursae and the uterus in all dogs. Twenty-two dogs that were clinically suspected of pyometra had sterile uterine content (“mucometra” cases); the remaining 118 had positive uterine cultures (“pyometra” cases) and septic peritoneal fluid was present in 10% of these cases. Of the 118 pyometra cases, 9 had unilateral and 15 had bilateral bacterial colonization of their ovarian bursae. However, the bacteria from the ovarian bursa were similar to those recovered from the uterine pus in only half of the cases. Furthermore, positive bursae were also seen in one mucometra dog (unilateral) and in four control dogs (two unilateral and two bilateral). The data illustrate that the canine ovarian bursa can harbor bacteria. The biological importance of these isolations remains unclear.     

Changes in germ cells population and in vitro oocyte maturation in female mice with imperforated vagina

This study characterized female mice with a congenital defect in their reproductive tract. In females derived from an outbred colony maintained in the Department of Genetics and Evolution, the frequency of the imperforated vaginae was approximately 2%. A consequence of this defect is infertility. Affected animals developed hydrometrocolpos (the uterus and vagina were greatly distended by fluid). Morphology of the ovary and oviduct was normal and similar to that of control mice. In the females with an imperforated vagina numerous corpora lutea were observed. Accordingly, we have found that both spontaneous as well as exogenous gonadotrophin-induced ovulation occurs in such females. Nevertheless, oocytes derived from ovaries of occluded females exhibited a partial block during in vitro maturation. Histological analysis of ovarian tissue revealed an increase in the number of primary follicles (type I follicles) and a decrease in the number of secondary and antral follicles (type IV and type VI follicles) when compared with control mice. The concentration of androgens in the ovarian tissue was higher in the affected females. Our data show that females with an imperforated vagina can be a useful model for studying the mechanism of genetic control of the development of the urogenital tract in mammals.     

Effects of androgen on scent marking and aggressive behavior of neonatally bulbectomized female Mongolian gerbils (Meriones unguiculatus)

Female gerbils were bilaterally bulbectomized, unilaterally bulbectomized or sham-operated at 2 days of age (Birth DAY = 0). As adults, the occurrence of scent marking and aggressive behavior was measured prior to and following administration of either testosterone propionate (TP) or oil. TP-treated sham operates showed increased scent marking; bilaterally bulbectomized and unilaterally bulbectomized females treated with TP did not. The display of aggressiveness increased for all females following TP. Neonatally bulbectomized animals treated with TP, however, were the most aggressive. Although androgen augments these species-typical response patterns, it seems dependent upon the integrity of the olfactory bulbs.     

Ovarian hydrobursitis in female camels (Camelus dromedarius): clinical findings, histopathology and fertility after unilateral surgical ablation

This study was undertaken to verify the clinical signs, incidence, location, etiology and pathology of ovarian hydrobursitis in infertile female camels and estimate the fertility after unilateral surgical ablation. Genital organs (n = 124) were examined in camels slaughtered at Makkah abattoir during Hajj of 2009. Infertile female camels (n = 142) presented for management to the Veterinary Teaching Hospital, Qassim University, Saudi Arabia, were clinically examined and ultrasound-scanned for the diagnosis of genital abnormalities. Twenty eight camels diagnosed with ovarian hydrobursitis were further investigated for the effect of unilateral surgical ablation on breeding outcomes. Surgical ablation was carried on 14 cases (treated group), the remaining 14 cases were followed as controls (control group). Both groups were observed for breeding results: 90 days non-return rate (90d NRR) and calving rate (CR). Removed bursae were sent to the laboratory for histopathological investigation. Results showed that the incidence of ovarian hydrobursitis was 6.5% in slaughtered camels and 33.8% in infertile females. Camels with hydrobursitis were concurrently affected with pyometra, uterine and vaginal adhesions or purulent endometritis. Histopathology reported degeneration and hyperplasia of the lining epithelium, mononuclear cells infiltration, focal aggregation of inflammatory cells, cystic dilatation of multi-acinal structures, tiny hemorrhages, and presence of hemosiderin-laden macrophages. The 90d NRR and CR of the surgically-treated cases were 64.3% and 50%, respectively. None of the untreated cases conceived. These results confirmed that ovarian hydrobursitis causes infertility in dromedary female camels and is associated with inflammatory genital conditions and surgical ablation in unilaterally affected animals presents a potential treatment.     

The differing responsiveness of the anterior- and the middle-anterior hypothalamic area to estradiol benzoate implant: inhibition of compensatory ovarian hypertrophy.

Estradiol benzoate (E2) was chronically implanted, unilaterally or bilaterally, for about 30 days in the anterior (A-AHA) or the middle (M-AHA) portion of the anterior hypothalamic area (AHA) of unilaterally ovariectomized (ULO) and intact cyclic rats. E2 unilaterally implanted in the A-AHA partially blocked and bilaterally implanted totally blocked compensatory ovarian hypertrophy (COH) in response to ULO. E2 implanted in the M-AHA induced ovarian atrophy in ULO rats. In M-AHA E2 implanted rats, ovulation was completely inhibited, vaginal smears became persistently cornified, serum FSH was drastically suppressed to 23-24% of the estrous level, LH was unremarkably changed. These effects were less pronounced when the implant was place in the A-AHA, i.e., ovulation was partially blocked only with bilateral implantation, vaginal cycles were irregular, serum FSH was suppressed to 66% and 44% of the estrous level after unilateral and bilateral implantation, respectively, LH was rather unchanged. Uteri were neither atrophic whether the implants was placed in the A-AHA or in the M-AHA. In normal cyclic rats, the effects of E2 implantation in the two areas were similar to those observed in ULO rats, except that the effects were evident even after unilateral implantation since the brain had not been compensated. The results allowed to indicate a functional subdivision of the ventral AHA, at least into the A-AHA and the M-AHA. The M-AHA was experimentally elucidated to be more estrogen sensitive than the A-AHA for monitoring of serum FSH, and was suggested to be involved in the episodic secretion of FSH. The inhibitory effect of estrogen on COH may primarily be mediated through the M-AHA and secondarily through the A-AHA.     

Female frog reproductive behavior elicited in the absence of the ovaries.

A release croak is emitted by unreceptive female frogs when they are clasped around the trunk; receptive females are silent. In one experiment, ovariectomized females given estradiol and/or progesterone continued to croak at a rate equivalent to that of unreceptive females. In another experiment, the frequency of emission of the croak was reduced significantly by artificial distension of ovariectomized females with fluid. These experiments fail to show a role for ovarian steroids in the reproductive behavior of the female frog, and demonstrate that breeding behavior can be induced in female frogs in the absence of ovarian hormones. These results are consistent with the interpretation that the release croak is inhibited by a mechanism that involves water uptake.     

Acute effects of unilateral sectioning the superior ovarian nerve of rats with unilateral ovariectomy on ovarian hormones (progesterone,testosterone and estradiol) levels vary during the estrous cycle

The present study analyzed the participation of the left and right superior ovarian nerves (SON) in regulating progesterone, testosterone, and estradiol serum levels in unilaterally ovariectomized rats on each day of the estrous cycle. For this purpose, ovarian hormone concentrations in serum were measured in animals with either sham-surgery, unilateral ovariectomy (ULO), unilateral sectioning of the SON, or sectioning of the SON innervation of the in situ ovary in rats with ULO.     

Retinal dystrophy in Sprague-Dawley rats.

A spontaneous retinal dystrophy was found in 4 percent of Sprague-Dawley-derived rats examined. The lesion occurred both unilaterally and bilaterally in equal frequency, but the incidence in the females was 2 times greater than in males. Retinal change consisted of focal or diffuse absence of the outer layers of the retina, but frank degenerative changes or progression of the lesion was not observed. The cause of the dystrophy was not determined, but its increased occurrence with increasing age of the rats suggests an age-related lesion.     

Effect of conspecifics on sexual maturation in female European pine voles (Pitymys subterraneus)

Using the number of large ovarian follicles (Type 8) as an indicator of sexual maturation we found that urinary compounds released by adult males accelerated puberty while urine from females suppressed hormonal activity in juvenile female European pine voles. The release of chemosignals that delayed puberty of juvenile females was not influenced by ovarian hormones; urine from ovariectomized females was as effective as urine from unoperated animals.     

Diethylstilbestrol versus estradiol as neonatal disruptors of the hamster (Mesocricetus auratus) cervix

The synthetic estrogen diethylstilbestrol (DES) is an established, estrogenic endocrine disruptor (ED). The Syrian golden hamster (Mesocricetus auratus) offers some unique advantages as an experimental system to investigate the perinatal ED action of DES and other estrogenic EDs. Previous analyses regarding the consequences of neonatal administration (100 microg) of DES versus estradiol-17beta (E2) showed that DES had a more potent disruptive effect on morphogenesis and gene expression in the uterus, oviduct, and ovary as well as in the testis and male accessory organs. The objectives of the present study were to describe the histopathological consequences of the two neonatal treatment regimens in the hamster cervix and to compare them with our previous observations in the hamster uterus. As previously found in the hamster uterus, DES was more potent than E2 as a neonatal disruptor of the hamster cervix in prepubertal animals and in ovarian-intact adult animals. However, the cervix-versus-uterus scenario diverged in animals that were ovariectomized prepubertally and then chronically stimulated with natural estrogen (E2). We confirmed previous observations that neonatal exposure to DES, but not to E2, permanently alters estrogen responsiveness in the adult hamster uterus, but neither neonatal treatment regimen affected estrogen responsiveness in the adult hamster cervix. These results suggest that an unidentified ovarian factor influences the extent of neonatal DES-induced disruption of the cervix, but not of the uterus, in hamsters.     

Dopaminergic metabolism in carotid bodies and high-altitude acclimatization in female rats

We tested the hypothesis that ovarian steroids stimulate breathing through a dopaminergic mechanism in the carotid bodies. In ovariectomized female rats raised at sea level, domperidone, a peripheral D2-receptor antagonist, increased ventilation in normoxia (minute ventilation = +55%) and acute hypoxia (+32%). This effect disappeared after 10 daily injections of ovarian steroids (progesterone + estradiol). At high altitude (3,600 m, Bolivian Institute for High-Altitude Biology-IBBA, La Paz, Bolivia), neutered females had higher carotid body tyrosine hydroxylase activity (the rate-limiting enzyme for catecholamine synthesis: +129%) and dopamine utilization (+150%), lower minute ventilation (-30%) and hypoxic ventilatory response (-57%), and higher hematocrit (+18%) and Hb concentration (+21%) than intact female rats. Consistent signs of arterial pulmonary hypertension (right ventricular hypertrophy) also appeared in ovariectomized females. None of these parameters was affected by gonadectomy in males. Our results show that ovarian steroids stimulate breathing by lowering a peripheral dopaminergic inhibitory drive. This process may partially explain the deacclimatization of postmenopausal women at high altitude.     

Ovarian steroids and hypothalamic norepinephrine release: studies using in vivo brain microdialysis

This study employed microdialysis in urethane-anesthetized female rats to monitor ovarian steroid-dependent changes in KCl-evoked levels of extracellular norepinephrine (NE) in the ventromedial hypothalamus. An initial KCl stimulus (Sl) increased NE from low or undetectable levels in all animals. A second KCl stimulus (S2) given several hr later evoked 40% less NE release than did Sl in ovariectomized (OVX) females or OVX females given only estrogen or progestin. In contrast, the two KCl-evoked NE releases were equivalent in OVX females administered both estrogen and progestin. These results suggest that ovarian steroids may act as presynaptic modulators of NE release in the ventromedial hypothalamus.     

Ovarian hydrobursitis in female camels (Camelus dromedaries): biochemical, bacterial and protozoal evaluation

The aim of this study was to evaluate female camels affected with ovarian hydrobursitis (n = 31) for hematological and biochemical findings and for bacterial and protozoal infections. Blood samples were obtained and surgical ablation of the affected bursa was performed. Bursal fluid, follicular fluid, and serum were subjected to hormonal and biochemical analyses. Bursal fluids were cultured and colonies were identified using BioMérieux Vitek two compact system. Passive haemagglutination test was used for detection of Trypanosoma evansi. Indirect ELISA technique was carried out for detection of anti-Hydatid cysts anti-bodies. Neutrophilia was found in the affected animals (P = 0.01) with tendencies for monocytosis (P = 0.06) and eosinophelia (P = 0.05). Bursal fluid had a tendency for high estradiol-17β concentration compared to blood serum (P = 0.07). Progesterone and cholesterol concentrations were similar in bursal fluid, follicular fluid and serum. Total protein, phosphorus, and magnesium concentrations were greater (P < 0.05) in the bursal fluid than in serum. Oligella urethralis, Alloiococcus otitis, Granulicatella adicens, Escherichia coli, Sphingobacterium thalpophilum, Streptococcus sanguinis, Aeromonas salmonicida, Pseudomonas stutzeri, Staphylococcus warneri, Staphylococcus hominis, and Rhizobium radiobacter were isolated from 46.7% of bursal fluids. T. evansi was positive in 9.7% of cases. None were positive for hydatid cyst. Accordingly, we suggest that the ovarian hydrobursitis syndrome is initially an inflammatory process and the accumulated bursal fluid is partially originated from follicular fluid.     

Sensitivity and specificity of bioassay of estrogenicity on mammary gland and uterus of female mice

Young intact (18 days of age) and adult ovariectomized (OV-X, ovariectomized between 21 to 24 days of age) C3H/Di mice were used to measure the estrogenicity on the basis of the growth response of mammary epithelial structures and weight of the uterus. The percentage area of the mammary fat pad occupied by mammary epithelial structures was progressively increased by 17beta estradiol from dose 0.001 microg.d(-1). The maximum effective dose of estradiol was 0.01 microg.d(-1) and the dose 10 microg.d(-1) of estradiol decreased mammary size to control levels (inverted-U-shaped dose-response curve). Progesterone alone progressively stimulated mammary growth in young intact females from dose 125 microg.d(-1), in adult OV-X animals from dose 1000 microg.d(-1). Both in young intact and adult OV-X animals, uterine weight progressively increased during estradiol treatment. Progesterone alone had no effect on uterine weight in young intact animals; in adult OV-X animals, uterine weight was increased starting from dose 250 microg.d(-1). Progesterone acted synergistically with estradiol to produce higher mammary growth than that in females treated with estradiol alone. The effects of a combination of estradiol plus progesterone in the mammary gland were mimicked by norethindrone acetate and inhibited by cortisol in both young intact and adult OV-X animals. Testosterone inhibited estradiol plus progesterone stimulated growth of mammary gland only in OV-X animals, but stimulated uterine weights in both young intact and adult OV-X animals. Spleen weight and size of mammary lymph nodes were not affected by estradiol, progesterone, norethindrone acetate or testosterone, but were decreased by cortisol. Cortisol also decreased the percent area of the mammary fat pad occupied by mammary epithelial structures, but had no effect on weight of the uterus. These results show that bioassay of estrogenicity in females is not specific. Mammary and uterine growth is stimulated not only by estrogens but also by progesterone and testosterone, respectively.