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At least 487 records · Page 27Linked to original sources
PubMed1992

Induction of ovulation and oocyte maturation of amphibian (Rana dybowskii) ovarian follicles by protein kinase C activation in vitro.

We previously reported that protein kinase C (PKC) activation induced meiotic maturation (germinal vesicle breakdown, GVBD) of Rana dybowskii follicular oocytes cultured in vitro without hormone treatment. The experiments reported here were carried out to establish whether ovarian follicles ovulated in response to PKC activation during culture. A phorbol ester, 12-O-tetradecanoylphorbol-13-acetate (TPA), was used for PKC activation. TPA addition (10 microM) to cultured ovarian fragments induced ovulation and maturation of the oocytes similar to that seen following addition of frog pituitary homogenate (FPH, 0.05 pituitary/ml) or progesterone (0.5 microgram/ml). Such changes were not observed when ovarian fragments were treated with inactive phorbol ester. The time course of TPA-induced ovulation was similar to that produced by FPH-stimulated ovulation. Both TPA- and FPH-stimulated ovulation and maturation were blocked by treatment with cycloheximide, forskolin (an adenylate cyclase stimulator), and 1-(5-isoquinolinylsulfonyl)-2-methyl-piperazine (H-7; a PKC inactivator). FPH treatment markedly increased progesterone levels in the medium during ovarian fragment culture whereas TPA treatment failed to elevate progesterone levels. Thus, TPA treatment mimics FPH and progesterone in inducing ovulation and meiotic maturation in cultured amphibian ovarian fragments. The data strongly suggest that PKC plays an important role in regulating ovulation as well as in modulating amphibian oocyte maturation during follicular differentiation.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1998

The selective prostaglandin endoperoxide synthase-2 inhibitor, NS-398, reduces prostaglandin production and ovulation in vivo and in vitro in the rat.

Two isoforms of prostaglandin G/H synthase, PGS-1 and PGS-2, catalyze the formation of prostaglandins (PG). Nonselective PGS inhibitors, e.g., indomethacin, reduce the number of ovulations and PG levels in many animal models. This study evaluated the effects of the selective PGS-2 inhibitor NS-398, compared to indomethacin, on ovulation number and on PG and steroid production both in vivo and in vitro in the rat. NS-398 reduced the synthesis of PGE2 in isolated, LH-stimulated preovulatory follicles incubated in vitro. The inhibition by NS-398 was similar to that of indomethacin. Maximal inhibition was noted from 0.1 microM. Neither progesterone nor cAMP production was affected by NS-398 or indomethacin. The effect of in vivo administration of NS-398 (1, 3, or 10 mg/kg BW, s. c.) to proestrous rats 1 h after the injection of an ovulatory dose of hCG was monitored in follicles extirpated 10 h after hCG. These follicles were incubated in vitro, and NS-398 dose-dependently reduced PGE2 production. The synthesis of cAMP and progesterone was not altered. In separate experiments, the same doses of NS-398 were injected to determine their effect on ovulation in vivo. The number of ovulations was decreased by the highest dose of NS-398. In the in vitro ovarian perfusion model, NS-398 (10 microM) reduced the number of ovulations initiated by LH and isobutylmethylxanthine. Lower doses of NS-398 (0.1 and 1 microM) were less effective. The production of prostanoids (PGE2, PGF2alpha, and 6-keto-PGF1alpha) was reduced in a dose-dependent manner by NS-398. The secretion of steroids was not affected. This study demonstrates that selective inhibition of PGS-2 by NS-398 reduces LH/hCG-stimulated production of prostanoids and the number of ovulations both in vivo and in vitro. These results provide direct evidence to strengthen the role of the inducible, granulosa cell-expressed PGS-2 as one of the key regulators in the ovulatory process and also document that the elevated and perhaps sustained levels of PG are obligatory for ovulation.

1-Methyl-3-isobutylxanthine↗
PubMed2005

Programming ovulation using estrogens for patients to time intercourse.

BACKGROUND: A woman wishing to conceive may be separated from her spouse at the time of ovulation. Moreover, some orthodox Jewish women have a unique problem when they are unable to initiate intercourse before ovulation. They are prohibited from participating in sexual relations from the start of menstruation until 7 days after the end of flow when they go to the ritual bath (mikveh). CASES: Two orthodox Jewish women who ovulated before restarting intercourse were treated with oral estrogens to delay ovulation. CONCLUSION: Women separated from their husbands at the time of ovulation and Jewish women who ovulate before ritual cleansing can effectively use oral estrogens to program ovulation.

Administration, Oral↗
PubMed2004

Identification of an ovulation rate QTL in cattle on BTA14 using selective DNA pooling and interval mapping.

Increased twinning incidence in beef cattle has the potential to improve production efficiency. However, phenotypic selection for twinning rate is difficult because of the trait's low heritability and the long time interval necessary to collect phenotypic records. Therefore, this trait and the correlated trait of ovulation rate are ideal candidates for marker-assisted selection. The objective of this study was to complete a genome-wide search for ovulation rate quantitative trait loci (QTL) in two related sire families. The families (paternal halfsib sires 839802 and 839803) were from a population of cattle selected for ovulation rate at the USDA Meat Animal Research Center, Clay Center, Nebraska. Putative ovulation rate QTL have previously been identified in the 839802 family on chromosomes 7 and 19; however, marker coverage in the original scan was not complete. This study fills the gaps in marker coverage of the earlier study by adding approximately 60 informative microsatellites to each sire family. Each family was genotyped using selective DNA pooling. Sons and daughters were included in either the high or low pool based on their estimated breeding value deviations from the mid-parent average (EBVMD) for ovulation rate. Approximately 40% (839802) and 26% (839803) of available progeny comprised the high and low pools combined. Pooled typing revealed possible associations (nominal P < 0.05) between ovulation rate and marker genotype for 11 and 15 microsatellites in the 839802 and 839803 families, respectively. Subsequent interval mapping strengthened support for the presence of an ovulation rate QTL on BTA14 (chromosome-wise P < 0.02).

Animals↗
PubMed1989

Predicting ovulation in the mare on the basis of follicular growth and serum oestrone sulphate and progesterone levels.

Follicular growth and hormone determinations were used to predict ovulation in the mare. Thirty Finnhorse mares were used for the investigation and 38 oestrous cycles were studied. The mares were examined by rectal palpation and ultrasonography every 6 hours during late oestrus. Daily blood samples were obtained for progesterone and oestrone sulphate determination. The preovulatory follicle grew 3 mm a day up to 2 days before ovulation. The size then remained constant, before diminishing by 2-3 mm during the last 12 hours. The maximal diameter of the follicle was 43 +/- 4 mm. In 89% of the follicles the round shape became more irregular before ovulation. During the last 24 hours before ovulation 37 of 38 follicles were regarded as mature on rectal palpation. The oestrone sulphate level was highest 24-48 hours before ovulation, the first decrease being observed most commonly around ovulation (+/- 1 day). The size of the follicle was the most reliable criterion in the prediction of ovulation.

Animals↗
PubMed2004

Influence of CRH and ACTH administration on endocrine profile and ovulation in sows.

Grouping of sows is a stressful event until the ranking is established. The purpose of this study was to simulate stress by repeated administration of porcine corticotropin releasing hormone (CRH) and adrenocorticotropic hormone (ACTH)/tetracosactide and to study its influence on endocrine profile and ovulation. Four multiparous sows were used and blood was collected every 2 h from the onset of pro-oestrus until 12 h after ovulation. The first oestrus after weaning was used to check ovulation and acclimate the sows to their environment. The second oestrus after weaning was used as control. At their third oestrus CRH (0.6 microg/kg) and at their fourth oestrus ACTH (5 microg/kg) were given every 4 h from onset of oestrus until ovulation. The total 'area under the curve' of cortisol was twofold larger in two of four sows during the CRH treatment period, and two- to fourfold larger (p < or = 0.05) during the ACTH treatment period, compared with the corresponding control period. In three sows, there was no clear effect of either CRH or ACTH on the levels of oestradiol 17beta, luteinizing hormone (LH) or on the timing of ovulation. One sow was different in all hormonal patterns and also in the timing of ovulation. In all four sows, ACTH treatment lowered the baseline level of prostaglandin F(2 alpha)-metabolite. Therefore, we conclude that stage of the oestrous cycle seems to be of importance when investigating the influence of exogenous administration of CRH/ACTH on hormonal pattern and ovulation time in the sow.

Adrenocorticotropic Hormone↗
PubMed2005

Lymphocytes and MHC class II positive cells in the female rabbit reproductive tract before and after ovulation.

In this study, we identified lymphocytes and MHC class II positive (MHC-II+) cells in the reproductive tract of female rabbits both before and after ovulation. CD43+ T cells were frequently present in the mucosa of the oviduct, cervix, and vagina, but far fewer positive cells were seen in the endometrium. The induction of ovulation did not change the cell density in these regions. KEN-5+ T cells and MHC-II+ cells were also frequently seen in the mucosa of the oviduct, cervix, and vagina both before and after ovulation. However, in the uterus, there were very few positive cells before ovulation, but the number increased dramatically after ovulation. Associated with the increase of KEN-5+ T cells, IL-2 mRNA expression in the uterus also increased after ovulation, suggesting that the uterus experienced an increase of T-cell activation. IgM- and IgA-positive B cells were not commonly seen in the reproductive tract and the induction of ovulation did not alter this. Our results suggest that the reproductive tract of female rabbits has the capacity to mount an immune response and that the immune cell distribution of the rabbit reproductive tract has some distinctive features compared with that found in other species.

Animals↗
PubMed1981

Morphological and functional relations of Graafian follicle growth to ovulation in women using ultrasonic, laparoscopic and biochemical measurements.

The daily growth rates of ovarian follicles were recorded ultrasonically for five days until ovulation in 56 spontaneously ovulating women and related to endocrine and clinical parameters. Over the 5-day period, the average diameter of the follicle destined to ovulate increased from 12 to 23 mm, the second largest follicle from 6 to 12 mm, the third largest follicle from 5 to 9 mm and the fourth largest follicle from 4 to 8 mm. Similar but lesser growth rates occurred in the follicles in the contralateral ovary. Ovulation occurred within 24 hours of the luteinizing hormone (LH) peak, and the mean peak diameter of the ovulating follicle was 23.2 +/- 0.3 (SEM) mm, (range 18-29 mm) before ovulation, and subsequent luteal function was judged to be normal. Follicular growth was most closely correlated with increasing peripheral blood oestrogen levels. In 16 women who had a laparoscopy within 12 hours of the last ultrasound and following the LH peak, the mean diameter of the largest follicle as measured by ultrasound (23.6 +/- 0.4 mm) was similar to that measured at laparoscopy (22.8 +/- 0.04 mm) and estimated from the volume of follicular fluid aspirated (average 5.8 +/- 0.2 ml), 22.5 mm. The follicular fluid levels of progesterone were high on the day of the LH peak and blood progesterone levels had risen significantly indicating that luteinization of the dominant Graafian follicles had already occurred prior to ovulation. This study confirms that ultrasonic monitoring provides a reliable measure of follicular growth and allows studies correlating morphological changes with both normal and abnormal endocrine function of the human ovary.

Adult↗
PubMed2001

Chronological aspects of ultrasonic, hormonal, and other indirect indices of ovulation.

OBJECTIVE: To improve prediction of ovulation in normal cycles. DESIGN: Collection of women's characteristics and their menstrual cycles. Monitoring and analysis of time relationships between several indicators of ovulation: transvaginal ultrasonography, cervical mucus, basal body temperature, urinary luteinising hormone, and ratio of urinary oestrogen to progesterone metabolites. SETTING: Each of eight natural family planning clinics was to study 12 women for at least three cycles. POPULATION: One hundred and seven normally fertile and cycling women aged 18 to 45. METHODS: Daily measurements of urinary luteinising hormone, follicle stimulating hormone, oestrone-3-glucuronide and pregnanediol-3alpha-glucuronide. Basal body temperature recording and cervical mucus checking. Transvaginal ultrasound examination of the ovaries. MAIN OUTCOME MEASURES: Delays between the expected day of ovulation according to the luteinising hormone peak or to ultrasound evidence and the expected days according to the other indices of ovulation. RESULTS: Ultrasonography was able to show evidence of ovulation in 283 out of 326 cycles. The average time lag between luteinising hormone peak and ultrasound evidence was less than one day (+0.46) but premature and late luteinising hormone-expected date of ovulation were observed in nearly 10% and 23% of cycles, respectively. Basal body temperature rise was observed in 98% of cycles. Cervical mucus peak symptom, rapid drop in the ratio of urinary metabolites, and luteinising hormone initial rise were all close to ultrasonographic evidence in more than 72% of cycles. CONCLUSIONS: For accuracy and practical reasons, the cervical mucus peak symptom, the ratio of urinary metabolites and luteinising hormone initial rise might be better indices of ovulation than the luteinising hormone peak.

Adult↗
PubMed1985

Influence of adrenoreceptor agonists and antagonists on ovulation in the rabbit ovary perfused in vitro.

Ovaries from sexually mature virgin rabbits were dissected free on both sides and cannulated in situ via that part of the aortic segment supplying the ovarian arteries. The ovaries were mounted in a closed, recirculating perfusion system for oxygenation in vitro. Ovulation was induced by human chorionic gonadotropin (hCG) given either i.v. (100 IU) or directly into the perfusion medium (20 IU). Follicular ruptures occurred in 42 out of a total of 54 ovaries. The in vivo route of hCG administration was found to be most efficient, with ovulations occurring after a mean of 11.5 h, which corresponds well with the incidence of ovulations in situ. The prostaglandin synthesis inhibitor, indomethacin, totally abolished the hCG-induced ovulations. beta-Adrenoreceptor stimulation in vitro with terbutaline or with noradrenaline in the presence of alpha-receptor blockade with phenoxybenzamine caused a significantly increased number of gonadotropin-induced ovulations. Phentolamine or phenoxybenzamine given alone reduced the number of ruptured follicles. Noradrenaline (in the absence of hCG) and clonidine augmented the incidence of ovulation. The results indicate that local adrenoreceptor mechanisms participate in the process of ovulation, both via alpha-adrenoreceptors (probably affecting the follicular smooth musculature) and beta-adrenoreceptors (possibly through some trophic or endocrine mechanism other than a mechanical factor).

Animals↗
PubMed1987

Characterization of an in vitro perfused rat ovary model: ovulation rate, oocyte maturation, steroidogenesis and influence of PMSG priming.

An in vitro perfused rat ovary model was characterized with respect to ovulation rate, oocyte maturation and steroidogenesis after priming with various doses of pregnant mare's serum gonadotrophin (PMSG) (10, 20 or 30 IU PMSG s.c. in the morning of day 28). In ovaries stimulated with LH 0.1 microgram ml-1 after 1 h of perfusion the number of ovulations was significantly higher in the 20 IU PMSG group than in the to IU PMSG group (6.8 +/- 1.0 ovulations per treated ovary versus 2.4 +/- 1.2, P less than 0.01). Priming with 30 IU PMSG did not result in significantly more or fewer ovulations than did 10 or 20 IU PMSG. No ovaries in the non-stimulated control groups ovulated. Oocytes retrieved directly at ovulation were mature (GVB or PB stage). Among oocytes retrieved from pre-ovulatory follicles punctured at 0, 2, 4, 6 and 8 h after stimulation with LH 0.1 microgram ml-1 there was an increasing number of oocytes with GVB (0/10 at 0 h and 10/10 at 8 h). Stimulation with LH resulted in a rapid release of progesterone, testosterone and oestradiol into the medium, whereas non-stimulated control ovaries exhibited a slow rise of all steroids throughout the perfusion period. It is concluded that priming with 20 IU PMSG in this model results in an optimal number of ovulations and that this model provides a useful tool in studies of various kinds of modifying influences on the ovulatory process.

Animals↗
PubMed1993

Advancing the time of ovulation in the mare with a short-term implant releasing the GnRH analogue deslorelin.

A small, biocompatible and short-term implant releasing 1.5 mg or 2.25 mg of the GnRH analogue deslorelin was evaluated in 140 Hanoverian (warm blooded) mares during the 1990 breeding season (Study I). Mares in oestrus and with a follicle 40 +/- 2 mm in diameter were assigned alternately to treatment (70) or remained as untreated controls. Implants were administered subcutaneously, and intervals to ovulation determined by rectal examination and ultrasound at 12-h intervals. Since results with both doses of deslorelin were similar, data were pooled. Deslorelin implantation resulted in ovulations in 65 of 70 mares within 48 h (93%), while only 5 of 70 control mares ovulated within the same time period (7%) (P < 0.01). Most induced ovulations (63%) occurred 36-48 h after implantation. In Study II, 4 groups of 12 Hanoverian mares each were treated with 3,000 or 5,000 iu hCG, or a 2.25 mg deslorelin implant, or received placebo. All treatments resulted in 100% ovulations within 48 h, versus 25% ovulations in controls (P < 0.01), and 63%, 75% and 86% of these ovulations occurred 36-48 h after treatment with 3,000 and 5,000 iu hCG and deslorelin respectively. Hormonal response to deslorelin in treated mares, sampled every 12 h, consisted of elevations of FSH and LH concentrations of > 200% and > 300% baseline values at 12 h (P < 0.001), of 67% and 79% at 24 h (P < 0.01) and of 35% and 49% at 48 h (P < 0.05), respectively. No local reactions at the implantation site were observed.

Alcohol Dehydrogenase↗
PubMed1997

Success rates when attempting to nonsurgically collect equine embryos at 144, 156 or 168 hours after ovulation.

The purpose of this study was to evaluate the exact age when the equine embryo reaches the uterus. The time of ovulation was determined by hourly ultrasound examinations starting 32 h after an injection of crude equine pituitary gonadotrophin or human chorionic gonadotrophin, or after the first of 4 injections of buserelin. Nonsurgical uterine flushings were carried out 144 h (Day 6), 156 h (Day 6.5) or 168 h (Day 7) after ovulation. Induction of ovulation was attempted in 101 oestrous cycles and 61 of 101 mares (60.4%) ovulated 32-44 h post injection. Sixty embryo collections were performed which yielded: 0/20 embryos at 144 h, 9/17 embryos (53%) at 156 h and 12/23 embryos (52%) at 168 h. The mean (+/- s.e.m.) diameter of the embryo was significantly greater (P<0.01) at Day 7 (244 +/- 15 microm) than at Day 6.5 (186 +/- 9.1 microm), and variability in size was observed among embryos collected from the same mare after synchronous natural multiple ovulations. These results suggest that; i) horse embryos enter the uterus between 144 and 156 h after ovulation, and ii) the time interval between ovulation and fertilisation in mares is inconsistent and/or embryonic development rate may differ between individual embryos.

Animals↗
PubMed1988

Human chorionic gonadotropin and luteinizing hormone-releasing hormone reverse the blockade of ovulation in pregnant mare's serum gonadotropin-primed immature rats by the anti-androgenic drug, hydroxyflutamide.

The present study was designed to examine mechanism(s) of the anti-ovulatory action of the anti-androgen, hydroxyflutamide (OH-F). Prepubertal rats were treated with 4 IU pregnant mare's serum gonadotropin (PMSG) (day -2) to induce first estrus and ovulation. They received OH-F in sesame oil or oil alone at 08:00 and 20:00 h on day 0 (the day of proestrus) and ovulations were assessed on the morning of day 1. Eighty-three percent of control animals ovulated with a mean of 7.7 +/- 1.1 corpora lutea per rat. Hydroxyflutamide blocked ovulation in all but 2 of the 12 rats receiving this drug alone. All of OH-F treated rats that received 5 and 25 IU human chorionic gonadotropin (hCG) ovulated with means +/- SEM of 9.1 +/- 0.1 and 7.3 +/- 1.4 corpora lutea per rat, respectively. The dose of 0.2 IU hCG was essentially ineffective, while the effect of 1.0 IU hCG was intermediate. At the dose of 20 ng and above (100 and 500 ng) luteining hormone-releasing hormone (LHRH) completely overcame the ovulation blockade in the OH-F treated animals, while a 4-ng dose was ineffective. At 18:00 h on the day of proestrus, serum LH levels in control animals were 17.56 +/- 2.60 ng/mL, which were 920% above basal levels (1.90 +/- 0.13) indicating a spontaneous LH surge. This surge was suppressed in OH-F treated rats. Injection of LHRH, at the dose of 20 ng and above, reinstated the LH release in OH-F treated animals. Thus, the anti-androgen, OH-F, inhibits ovulation in PMSG-treated immature rats through its interference with the preovulatory LH surge; the inhibition can be reversed by hCG or LHRH. Hydroxyflutamide does not appear to interfere at the level of the pituitary, but may have direct action at the hypothalamic and (or) extrahypothalamic sites involved in the generation of positive feedback signals that control LH release.

Anilides↗
PubMed2005

Effects of injecting thymulin into the anterior or medial hypothalamus or the pituitary on induced ovulation in prepubertal mice.

UNLABELLED: In prepubertal mice, subcutaneous thymulin injection before equine chorionic gonadotrophin (eCG) treatment simulates ovulation; seemingly, the thymulin could be acting at the hypothalamus-pituitary axis level. OBJECTIVE: This study was designed to analyze the effects of injecting thymulin into the hypothalamus or pituitary on induced ovulation of prepubertal mice. METHOD: Female mice, 19 days old, were anesthetized with ether and injected with saline solution or thymulin into the anterior or medial hypothalamus or the pituitary and treated with eCG when 20 days old. The ova shed were counted and serum concentrations of 17beta-estradiol were measured. In the ovaries, the morphometrical analysis was performed and the atresia evaluated. RESULTS: Ether anesthesia treatment blocked eCG-induced ovulation in almost all animals. Mice anesthetized and treated with eCG and gonadotrophin-releasing hormone (GnRH) or human chorionic gonadotrophin (hCG) ovulated a full quota of ova. Injecting saline solution into the anterior or medial hypothalamus or the pituitary did not reduce the blocking effects of ether anesthesia on induced ovulation, but the incidence of atretic follicles was higher. Injecting thymulin directly into the anterior hypothalamus did not restore ovulation, nor diminish the number of atretic follicles. In contrast, injecting thymulin into the medial hypothalamus restored the ovulation ratio and decreased the percentage of atretic follicles. Similar results were obtained by injecting thymulin into the pituitary, though thymulin treatment in the pituitary resulted in a higher number of ova shed and lower follicular atresia. CONCLUSION: The present results suggest that thymulin acts at the medial hypothalamus level, facilitating the release of GnRH and at the pituitary level regulating gonadotrophin release.

Animals↗
PubMed1975

Rhythms of progesterone and corticosterone in the pms-treated rat: relationship to ovulation.

Precocious ovulation was induced in 26-day-old rats by means of 25 IU pregnant mare's serum gonadotrophin (PMS). Rats were given injections at either 09.00 or 16.00 in order to determine whether the course of pubertal changes in corticosterone (B), progesterone (P) or time of ovulation would be dependent upon the time of injection. Blood samples were collected by decapitation at 4-h intervals on the day of expected ovulation (day 28). In saline-treated controls at 28 days of age there was a demonstrable daily variation in both serum B and P with maximum values at 16.00 and minimum values at 08.00. In rats given PMS at 09.00, there was a peak of P and B at 16.00 on day 28 but the values were higher than in controls. Ovulation took place at 24.00 on day 28-29. In rats given PMS at 16.00 the pattern of P and B was different, with continual high values from 16.00 to 04.00 at 28 days of age; ovulation took place later in this group (between 02.00-08.00 on day 28). It can be concluded that there is a daily rhythm of P a few days before puberty and that the induction of precocious ovulation with PMS is associated with a different pattern of B and P and a different time of ovulation depending upon when PMS is administered.

Adrenal Glands↗
PubMed1978

Effects of hypothalamic deafferentation on ovulation and estrous cyclicity in the female guinea pig.

The effects of hypothalamic deafferentiation on the estrous cycle and ovulation were studied in the mature female guinea pig, a spontaneous ovulator with a true luteal phase. Animals were stereotaxically deafferentated using the Haláxz knife technique. (1) Large complete deafferentation of the medial basal hypothalamus (MBH; arcuate nucleus, median eminence (ME), and a ventral part of the ventromedial nucleus) did not block cyclic ovulation, although the cycle became slightly prolonged. (2) Small complete deafferentation which excluded the ventromedial nucleus from the MBH and partially damaged the arcuate nucleus in anovulation and constant closure of the vaginal membrane. (3) Large anterior deafferentation, which eliminated neural afferent from medial preoptic area (MPO), suprachiasmatic portion of the preoptic nucleus (POSC) and the anterior periventricular area to the MBH, was effective in blocking ovulation and inducing constant vaginal opening. In most of the cases, the knife passed rostral to the suprachiasmatic nucleus (SCN). (4) Small anterior deafferentation at the caudal border of the optic chiasma did not block ovulation if the arcuate nucleus and ME were intact, although the cycle sometimes became irregular. (5) Posterior deafferentation at the level of the mammillary bodies failed to interfere with cyclic ovulation. It is concluded that, in the guinea pig, the deafferentated MBH is capable of sustaining both tonic and phasic secretion of gonadotropins (Gns) necessary for maintenance of normal estrous cycles and ovulation. However, this function of the MBH may also be modulated by facilitatory and inhibitory influences arising from extrahypothalamic areas.

Afferent Pathways↗
PubMed1987

Correlation between the endocrine profile of ovulation and the ultrasonically detected 'double contour' of the preovulatory follicle.

The exact prediction of ovulation is becoming more important in the management of infertile couples. The routine methods used to monitor ovulation are plasma levels of estradiol and luteinizing hormone, and ultrasonic scanning of graafian follicle diameter. Ovulation is known to occur at a wide range of follicular diameters and it cannot be used as a single predictor of ovulation. In a previous study we described the preovulatory double contour of the dominant follicle occurring a few hours before ovulation. The purpose of this study was to correlate this sign with the hormonal profile to determine whether it can be used as a single parameter in predicting ovulation. The results demonstrate a close relationship between the LH peak and the appearance of the double contour which can be used as a reliable predictor of impending ovulation.

Estradiol↗