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PubMed1995

Characteristics of urinary luteinizing hormone (LH) during the induction of LH surges of different magnitude in blood.

Urinary luteinizing hormone (LH) testing has been proposed as a reliable method for the prediction of ovulation but its accuracy has been challenged by some studies. To check how accurately the oscillations of urinary LH reflected the plasma changes, surges of LH of different magnitude and duration were artificially induced in plasma and the hormone was measured simultaneously in urine. Post-menopausal women (n = 16) were stimulated during 1 week with a combination of transdermal oestradiol (400 micrograms) and i.m. progesterone (25 mg on day 4, 50 mg on day 5) to obtain an LH discharge comparable with the pre-ovulatory LH peak. A short and moderate peak of LH was induced by the i.v. injection of 100 micrograms gonadotrophin-releasing hormone (GnRH) in six premenopausal women, whereas an LH discharge of higher amplitude and longer duration was induced by a single dose of 0.3 mg s.c. buserelin. The total urine production of the day was fractionated into 8 h periods. LH was measured by a commercial radioimmunoassay. Unambiguous peaks of LH were detected in the urine of all the women stimulated with either oestradiol plus progesterone or buserelin, but in only three out of the six women receiving GnRH. The urine LH reproduced the plasma changes of the hormone with short delay since the peaks were mostly detected in the same time fraction in which the serum discharge occurred.

Adult↗
PubMed1994

CA-125 levels in cervical mucus during the menstrual cycle.

OBJECTIVE: To determine CA-125 levels in cervical mucus (CM) during the menstrual cycle and their relationship to gonadal steroids and ovulation. DESIGN: Prospective study. SETTING: Two academic tertiary referral centers. PARTICIPANTS: Thirteen women with a normal fertility work-up. INTERVENTIONS: CA-125 and protein concentrations were measured in CM aspirated from the endocervical canal on alternate days in the early follicular and luteal phases and on a daily basis during the periovulatory period. Results were correlated with hormonal determinations, serum CA-125 levels, and ultrasound examination. RESULTS: Twenty ovulatory nonconceptional cycles were analyzed. Although the mean (+/- SD) concentration of CA-125 in CM (173,900 +/- 128,900 arbitrary U/mL) appeared relatively constant along the cycle, a large variation among the different samples was observed, ranging from 9,000 to 830,000 arbitrary U/mL. No clear trend could be detected as related to hormonal changes and ovulation. However, when the mucus CA-125 concentration was multiplied by the total volume of the correspondent sample, a clear periovulatory increase of total CA-125 levels was found. This was further supported by a similar trend showed by the calculated CA-125:protein concentration ratio. CONCLUSIONS: CA-125 is present in CM in high concentrations that vary widely along the cycle. Although no cyclical variation in CA-125 concentration could be determined, there was an apparent increase of total CA-125 levels parallel to the augmented mucus production during the periovulatory period. This further suggests a possible involvement of this glycoprotein in the secretory process of endocervical glands.

Adult↗
PubMed1994

Insulin-like growth factor binding proteins in serum and follicular fluid from women undergoing ovarian stimulation with and without growth hormone.

The effects of supplementary growth hormone (GH) upon insulin-like growth factor binding proteins (IGFBP) in serum and ovarian follicular fluid were investigated in women undergoing buserelin-human menopausal gonadotrophin (HMG) ovulation induction for in-vitro fertilization. IGFBPs were detected by Western ligand blotting (WLB) or radioimmunoassay (IGFBP-3) and were shown in the present study to increase and decrease in patients with diseases of GH excess or deficiency. In the women undergoing treatment for ovulation induction, radioimmunoassay of IGFBP-3 gave results which were consistent with the well-documented GH dependency of this protein, increasing in the serum when GH was administered at the same time as buserelin-HMG. In contrast there were no consistent patterns in the abundance of the IGFBPs in serum and follicular fluid examined by WLB whether or not the patient was receiving GH, and the IGFBPs varied independently of the result obtained by radioimmunoassay. Other studies have shown that during pregnancy a serum protease can dramatically decrease the detection of the IGFBPs on the WLB. However, there was no evidence for a protease in the serum or follicular fluid from these nonpregnant women undergoing ovulation induction. Tissue availability of IGFs is probably regulated by the BPs, so that data would suggest that in normal women, neither ovarian activity nor GH at pharmacological concentrations is the primary regulator of the IGFBPs, which are likely to be regulated by some other factor(s), e.g. nutrition. These data may account for the lack of consistent clinical improvement in studies investigating the hypothesis that supplementary GH during ovulation induction with gonadotrophins would be beneficial.

Blotting, Western↗
PubMed1982

Maternal anti-fetal cytotoxic antibody responses of equids during pregnancy.

The maternal immunological response to the developing equine fetus was investigated in 69 pregnancies of various genotypes. In normal intraspecies horse pregnancy (N = 16), 94% of mares produced strong cytotoxic antibody responses to paternal histocompatibility antigens which were first detectable between 44 and 70 days after ovulation. In all other types of pregnancy examined (intraspecies donkey, N = 19; interspecies mule, N = 6; interspecies hinny, N = 2; extraspecies horse-in-donkey, N = 3; and extraspecies donkey-in-horse, N = 21), antibody production was observed less frequently, and sometimes with a more irregular onset. However, the dominant pattern of response was similar to that observed in intraspecies horse pregnancy. Although the development of cytotoxic antibody correlated well with the formation of the equine endometrial cups, histological and serological evidence demonstrated that the accumulation of lymphocytes which occurs around the endometrial cups in intra- and interspecies pregnancies, and in the endometrial stroma in contact with trophoblast in extraspecies donkey-in-horse pregnancies which lack endometrial cups, can occur in the absence of a detectable cytotoxic antibody response. The cytotoxic antibody produced by mares carrying extraspecies donkey conceptuses appeared to be directed primarily against donkey alloantigens, and not species-specific antigens, emphasizing the importance of maternal recognition of paternally derived fetal histocompatibility antigens during equine pregnancy.

Animals↗
PubMed2004

Pregnancy rates after timed AI of heifers following removal of intravaginal progesterone inserts.

Reproductive performance of dairy heifers was compared for each of 2 synchronization protocols: The first group of 54 heifers was synchronized using intravaginal progesterone inserts (CIDR) plus estradiol cypionate (ECP) on d 0, PGF(2alpha) on d 7, and ECP again on d 8 (CIDR-ECP); a second group of 56 heifers was synchronized using CIDR and ECP on d 0, PGF(2alpha) on d 7, and GnRH on d 9 (CIDR-GnRH). All heifers received timed artificial insemination (TAI) at 48, 56, or 72 h after CIDR removal on d 7. Pregnancy diagnosis was conducted by ultrasonography 32 +/- 1 d post AI to confirm pregnancy and at 60 +/- 1 d post AI to determine embryo survival. Ovaries were monitored by ultrasonography daily from d 0 to 7 and twice daily from d 8 to ovulation to examine emergence of a new wave of follicles, size of the ovulatory follicle, and timing of ovulation on 15 heifers per protocol. New follicular development was detected 3.7 +/- 0.2 d after CIDR insertion. Heifers receiving CIDR-ECP had a shorter interval from CIDR removal to ovulation than heifers receiving CIDR-GnRH (63.8 +/- 3.0 vs. 71.6 +/- 2.3 h, respectively); however, ovulation occurred 39.8 +/- 3.0 h after ECP or 23.6 +/- 2.3 h after GnRH. Diameters of ovulatory follicles did not differ between treatments. Overall pregnancy rate for synchronized heifers was 60.1%, and embryo survival was 98%. Pregnancy rate for heifers synchronized with CIDR-ECP was 63.0% and similar to that in heifers synchronized with CIDR-GnRH (57.1%). Pregnancy rate was affected by time of AI for heifers synchronized using CIDR-ECP but not for those synchronized with CIDR-GnRH. Heifers in the CIDR-ECP group that were inseminated 56 h after CIDR removal had a higher pregnancy rate (81.0%) compared with heifers inseminated 48 (66.7%) or 72 h (50.0%) after CIDR removal. Either ECP or GnRH used in a CIDR-based TAI program in dairy heifers can achieve acceptable reproductive performance.

Administration, Intravaginal↗
PubMed1995

Dirithromycin increases ethinyl estradiol clearance without allowing ovulation.

OBJECTIVE: To use a novel, sensitive study design to detect a potential oral contraceptive (OC) and dirithromycin drug interaction by assessing the pharmacokinetics of the ethinyl estradiol (E2) component of a common OC and the potential failure of OC effectiveness. METHODS: In this nonblinded study, 20 healthy women using Ortho Novum 7/7/7-28 were selected for a three-OC-cycle study. Baseline measures included E2 and progesterone serum levels on days 21, 23, 25, and 27 of cycle one and days 1, 3, 5, and 7 of cycle two. During cycle two, 24-hour blood sampling and radioimmunoassay analysis for ethinyl E2 pharmacokinetics were performed on day 8 and pelvic ultrasound on day 13. Oral dirithromycin 500 mg/day for 14 days began on day 21 of cycle 2. After starting dirithromycin, cycle two and three serum E2, progesterone, and serial ethinyl E2 levels and pelvic ultrasound replicated the baseline schedule. Ovulation was assumed if E2 concentration was greater than 50 pg/mL, progesterone concentration was greater than 3 ng/mL, or if an ovarian cyst greater than 10 mm was present on ultrasound. RESULTS: Pharmacokinetic analysis demonstrated a small (7.6%) but statistically significant decrease (P = .03) in the mean ethinyl E2 24-hour area under the curve and an increase in apparent oral clearance. No woman ovulated, based on E2 levels and progesterone concentrations or ultrasound. CONCLUSION: Dirithromycin increased the apparent oral clearance of ethinyl E2. The clinical importance of the interaction may be negligible because no woman ovulated or had compromised OC effectiveness in this small series.

Adolescent↗
PubMed2001

Seasonal variation in preovulatory events associated with synchronization of estrus in dwarf goats.

This experiment was conducted to define the temporal relationships among estrus, the LH surge and ovulation after estrus synchronization in dwarf goats and to assess the effect of season on these parameters. In November (breeding season), March (transition period) and July (non-breeding season), estrus was synchronized in 12 dwarf goats by means of intravaginal sponges containing 60 mg medroxyprogesterone acetate (MAP) for 10 d, coupled with 125 microg cloprostenol i.m. 48 h before sponge removal and 300 IU eCG i.m. at sponge removal. A different group of animals was used during each time period. Onset of estrus was monitored using two males, and blood samples for the measurement of plasma LH were collected at 2-h intervals from 24 to 60 h after sponge removal. Ovulation was confirmed by laparoscopy at 54 and 72 h after sponge removal. A seasonal shift was detected in the intervals to onset of estrus, LH surge, and ovulation after sponge removal (P<0.05), with sponge removal to onset of estrus being shorter (P<0.05) in November (25.0 +/- 1.56 h) and July (28.9 +/- 2.43 h) than in March (40.9 +/- 3.27 h). The intervals between onset of estrus and the LH surge and between the LH surge and ovulation were found to be constant throughout the different seasons. An optimal time for breeding, artificial insemination, oocyte and embryo recovery, and embryo transfer may be predicted using information gained from these studies.

Administration, Intravaginal↗
PubMed1997

Vaginal temperature is not related to the time of ovulation in sows.

The relationship between vaginal temperature and ovulation time was studied in sows. The vaginal temperature was measured continuously between Day 4 and Day 10 after Altrenogest-treatment in 10 sows. Oestrus was checked with a vasectomized boar at 8-h intervals, and during oestrus, ovulation time was checked with transrectal ultrasonography at 2-h intervals between 07:00 h and 23:00 h. Two sows ovulated between 23:00 h and 07:00 h, and these sows were taken out of the experiment. In the eight remaining sows, a clear day/night rhythm in vaginal temperature was found: between 03:00 h and 09:00 h, vaginal temperature (LSM +/- sem, corrected for sow) was on average 38.2 +/- 0.01 degrees C; between 15:00 h and 21:00 h, vaginal temperature was on average 38.5 +/- 0.01 degrees C (P < 0.001). Between 4 days before ovulation and 2 days after ovulation, no changes in temperature could be found that were related to ovulation time in any of the sows. Therefore, in sows, changes in vaginal temperature cannot be used as a predictor for ovulation time, and consequently cannot be used to predict the best time for insemination.

Animals↗
PubMed2003

A randomized trial on the impact of starting day on ovarian follicular activity in very low dose oral contraceptive pills users.

In a randomized trial, the impact of starting day (the first and the seventh day of the period) on ovarian follicular activity was assessed during administration of a very low dose of oral contraceptive pills (20 microgram (mcg) ethinyl estradiol (EE) and 75 mcg gestodene (GS) [Meliane, Schering, Germany]). One hundred and sixty healthy women aged: 23-44 years, who had a regular cycle, and who were not using any type of oral contraceptive (OCs) steroid were studied at the Family Planning Clinic of King Chulalongkorn Memorial Hospital, Bangkok, Thailand. In the trial, each subject received a package of Meliane. They were blockwise randomized, 1:1 ratio; in the first group, subjects began their pills on the first day of their period (n = 80) and the other group, the seventh day of their period (n = 80). During the treatment cycle, ovarian activity was evaluated by transvaginal sonography (TVS) to determine the follicular-like structure (FLS). Ovulation was defined as the dominant FLS detected by TVS and followed-up every other day until its collapse. It occurred in 0 of 77 cases who started on the first day of their period and occurred in 8 of 78 cases of the group which started on the seventh day of their period. The difference was of statistical significance (p = 0.006). The result of this clinical trial is beneficial information for users of OCs containing 20 mcg EE who delay start of the OCs package.

Adult↗
PubMed2005

Arabidopsis thaliana Somatic Embryogenesis Receptor Kinase 1 protein is present in sporophytic and gametophytic cells and undergoes endocytosis.

Arabidopsis thaliana plants expressing AtSERK1 fused to yellow-fluorescent protein were generated. Fluorescence was detected predominantly at the cell periphery, most likely the plasma membrane, of cells in ovules, embryo sacs, anthers, and embryos and in seedlings. The AtSERK1 protein was detected in diverse cell types including the epidermis and the vascular bundles. In some cells, fluorescent receptors were seen in small vesicle-like compartments. After application of the fungal toxin Brefeldin A, the fluorescent receptors were rapidly internalized in the root meristem and root vascular tissue. We conclude that the AtSERK1 receptor functions in a common signalling pathway employed in both sporophytic and gametophytic cells.

Arabidopsis↗
PubMed1987

Evidence for a role of intrauterine infections in the pathogenesis of cystic ovaries in postpartum dairy cows.

Patterns of uterine microbial recovery and serum concentrations of prostaglandin F(2alpha) metabolite (PGFM), cortisol, luteinizing hormone (LH) and progesterone (P4) were determined in normal postpartum dairy cows (n = 12) and in postpartum cows that developed cystic ovaries (n = 12). Palpation per rectum, ultrasound examinations of the reproductive tract and endometrial swab harvest were carried out once every 4 d during the first month postpartum. Daily blood samples were collected during the first 30 d postpartum and every other day until Day 60 postpartum for hormone assay. Bacterial growth densities of cultures of uterine swabs were high in cows that developed cystic ovaries. Cysts were detected between Day 8 and 16 postpartum and persisted for a period of 18.6 +/- 9.9 d (range 8 to 41 d), followed by spontaneous regression and ovulations. Serum PGFM and cortisol were elevated for several days prior to detection of cystic ovaries but not prior to first postpartum ovulations. Serum LH concentrations in cystic cows were at basal concentrations prior to discovery of cysts. The results suggest that postpartum intrauterine infections may provoke increased secretion of prostaglandin F(2alpha) and cortisol associated with the formation of cystic ovaries in dairy cows.

Journal Article↗
PubMed1997

Urinary LH, plasma LH and progesterone and their clinical correlates in the periovulatory period of domestic bitches.

Ten bitches were examined daily from pro-oestrus until metoestrus to correlate endocrine, vaginoscopic and cytological assessments of stage of the oestrous cycle. It was considered that oocytes were fertile by 4 days after the LH peak assuming a 2 day lag before ovulation and a further 2 days for oocyte maturation. Eight bitches showed a plasma LH peak and five bitches showed a peak in urinary LH, which corresponded to the plasma LH peak. Plasma concentration of progesterone increased in all bitches. Initially, this coincided with the preovulatory LH peak and reached values of 7.7 +/- 0.6 ng ml-1 4 days later. The peak in number of a nuclear vaginal epithelial cells and the onset and peak of vaginal mucosal shrinkage with angulation occurred on average 2.4 +/- 1.5, 2.1 +/- 2.4, and 6.1 +/- 1.1 days after the plasma LH peak, respectively, giving sufficient precision to be of practical value in estimating the fertile period. However, the onset of vulval softening, changes in rectal temperature and colour of the vulval discharge varied considerably. Nine of the bitches were mated at the time of highest percentage of a nuclear cells, coinciding with the onset of the period of vaginal mucosal shrinkage with angulation. Eight became pregnant. Selected clinical parameters are therefore useful in predicting the optimal mating time of bitches, as is detection of plasma progesterone concentration higher than about 8 ng ml-1, but the latter appears to be the most reliable method. Detection of the urinary LH peak was more difficult and as yet offers no practical advantages except from the point of view of easy sample collection.

Animals↗
PubMed1984

The measurement of urinary LH, by a solid-phase chemiluminescence immunoassay.

Ovulation in women may be predicted or detected by a simple, solid-phase, chemiluminescence immunoassay for the measurement of urinary LH. An IgG fraction of a donkey antiserum to rabbit immunoglobulins is passively adsorbed to the walls of polystyrene tubes. Human chorionic gonadotrophin-succinyl-butyl-ethyl-isoluminol and a primary antibody (rabbit anti-human LH) is incubated with samples of early morning urine. After the binding reaction, the solution is removed by aspiration. The antibody-bound fraction is washed twice with buffer. Sodium hydroxide is added and the mixture incubated. After cooling, luminescence is initiated by oxidation of the label with microperoxidase/hydrogen peroxide and the signal integrated. The method has been evaluated in terms of sensitivity, within- and between-batch precision, bias and parallelism. The time interval between the peak day of LH in EMU and maximum follicular diameter during 38 menstrual cycles was -24 h (11%), O h (50%), + 24 h (28%) and + 48 h (11%).

Buffers↗
PubMed1992

Use of melengestrol acetate and gonadotropins to induce fertile estrus in seasonally anestrous ewes.

Ewes of three genotypes (Hampshire, n = 59; Rambouillet, n = 36; crossbred, n = 57) were used to determine the efficiency of melengestrol acetate (MGA) and(or) PG-600 (a combination of pregnant mare's serum gonadotropin and human chorionic gonadotropin) in inducing fertile estrus in seasonally anestrus ewes. Ewes were assigned randomly, within genotype, to treatments in a 2 x 2 factorial arrangement. Treatments were control, .125 mg of MGA given twice per day for 9 d (MGA), a single 5-mL injection of PG-600 (PG-600), and the combination of treatments MGA and PG-600 (MGA/PG-600). Feeding of MGA began on May 14, 1990, and ended on May 23. Injections of PG-600 were given immediately after the last feeding of MGA or vehicle on May 23. All ewes were exposed to fertile, brisket-painted rams on May 24 (d 0) for 40 d. Ewes were checked for estrus twice daily for 9 d. Laparoscopy was performed, to assess ovulation rate (OR), on d 6 for ewes that were not detected in estrus and on d 12 for ewes that exhibited estrus. Percentage of ewes mated was increased by MGA (P less than .001). Ovulation rate of ewes exposed to rams was increased by PG-600 (P less than .01) and this effect was enhanced by MGA (P less than .05), whereas MGA alone tended to decrease OR (P less than .10). Melengestrol acetate decreased the interval to lambing by 6.5 d (P less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Anestrus↗
PubMed2001

A Doppler ultrasonographic study of cyclic changes of ovarian perfusion in the Beagle bitch.

Changes in intraovarian arterial blood flow were monitored by means of colour-coded and pulsed Doppler ultrasonography in Beagle bitches during the normal oestrous cycle (n = 11) and pregnancy (n = 3), and at PGF(2alpha)-induced luteolysis (n = 4). The ultrasonographic findings were related to the reproductive stage of the bitch, as determined by vaginoscopical and cytological criteria, and by the concentrations of oestradiol, LH and progesterone in peripheral blood plasma. Colour-coded Doppler ultrasonography was used to visualize and estimate intraovarian vascularization, and pulsed Doppler ultrasonography was used to measure the arterial blood flow. The systolic and diastolic peak velocities, the end-diastolic velocity, and the pulsatility index and resistance index were calculated for quantitative analysis of the Doppler waveforms. Intraovarian perfusion increased gradually during pro-oestrus. A marked enhancement of intraovarian colouring and blood flow velocities, and a decline in the indices for pulsatility and resistance were observed in the preovulatory period. Maximum perfusion was observed at ovulation and during the early luteal phase. Significant differences (P < 0.05) were detected for the values of all calculated Doppler parameters 2 days before and 2 days after ovulation. Intraovarian blood flow decreased gradually in accordance with luteal regression. Treatment with PGF(2alpha) caused a distinct decline in luteal activity and a concomitant reduction in intraovarian perfusion. The values of blood flow parameters found during the luteal phase of pregnant bitches were comparable to those of the normocyclic bitches. Doppler ultrasonography of the intraovarian arteries in bitches provides complementary information about cyclic changes of ovarian function.

Animals↗
PubMed2002

Proteins and enzymes in uterine lavage fluid of postpartum and nonparturient mares.

Uterine lavage fluids from postpartum and nonparturient mares were compared to determine when the normal secretory capacity of the postpartum uterus is restored. Lavage fluids were obtained from cyclic nonparturient mares on the second, fourth or fifth day of oestrus, and 3, 8, or 14 days after ovulation (seven mares/sampling day). Twelve intact postpartum mares were sampled 1 to 28 days postpartum (group A: 1, 6, 12 and 20; group B: 2, 8, 14 and 24; group C: 4, 10, 16 and 28 days postpartum; four mares/group). Three ovariectomized (OVX) postpartum mares were sampled as mares in group C. Samples were analysed for neutrophils, bacteria, total protein concentration, proteolytic and antiproteolytic activities and for various lysosomal enzyme activities. In nonparturient mares, activities of acid phosphatase, beta-glucuronidase (B-Gase), and N-acetyl-beta-D-glucosaminidase (NAGase) in uterine lavage fluids were significantly higher in mid- and late-dioestrus than in mid- to late-oestrus (p < 0.05). Lysozyme concentration, trypsin-inhibitor capacity (TIC), and plasmin activity were below the detection limit in nonparturient mares. One to four days postpartum, total protein, acid phosphatase, B-Gase, and NAGase were high but declined rapidly thereafter. Lysozyme and plasmin activities were high 1 to 6 days postpartum. TIC peaked around day 6 postpartum. On day 16 postpartum, acid phosphatase, B-Gase, and NAGase, being progesterone-dependent, tended to be higher in intact mares than in OVX ones (p < 0.1). Total protein and lysozyme concentrations, TIC, and B-Gase (p < 0.01) and acid phosphatase (p < 0.05) activities were significantly higher in parturient mares during postpartum oestrus than in oestrous nonparturient mares. High total protein concentration and TIC, and detectable lysozyme and plasmin activities during postpartum oestrus were associated with uterine inflammation. During dioestrus, differences between postpartum and nonparturient mares were not statistically significant and suggested that the endometrium of postpartum mares had resumed its normal secretory capacity by this time.

Acetylglucosaminidase↗
PubMed2003

Effect of time of ovulation and sperm concentration on fertilization rate in gilts.

In normal production practices, sows and gilts are inseminated at least twice during estrus because the timing of ovulation is variable relative to the onset of estrus. The objective of this study was to determine if a normal fertilization rate could be achieved with a single insemination of low sperm number given at a precise interval relative to ovulation. Gilts (n=59) were randomly assigned to one of three treatment groups: low dose (LD; one insemination, 0.5 x 10(9) spermatozoa), high dose (HD; one insemination, 3 x 10(9) spermatozoa) or multiple dose (MD; two inseminations, 3 x 10(9) spermatozoa per insemination). Twice daily estrus detection (06:00 and 18:00 h) was performed using fenceline boar contact and backpressure testing. Transrectal ultrasonography was performed every 6 h beginning at the detection of the onset of standing estrus and continuing until ovulation. Gilts in the LD and HD groups were inseminated 22 h after detection of estrus; MD gilts received inseminations at 10 and 22 h after detection of estrus. Inseminations were administered by using an insemination catheter and semen was deposited into the cervix. The uterus was flushed on Day 5 after the onset of estrus and the number of corpora lutea, oocytes, and embryos were counted. Time of insemination relative to ovulation was designated as 40 to >24 h, 24 to >12 h, and 12 to 0 h before ovulation and >0 h after ovulation. The LD gilts had fewer embryos (P<0.04), more unfertilized oocytes (P<0.05) and a lower fertilization rate (P<0.07) compared to MD gilts. The effects of time of insemination relative to ovulation and the treatment by time interaction were not significant. We conclude that a cervical insemination with low spermatozoa concentration may not result in acceptable fertility even when precisely timed relative to ovulation.

Animals↗
PubMed1977

Luteinizing hormone-releasing hormone, ovariectomy, and silastic vaginal rings in the Rhesus monkey.

The interaction of estradiol and luteinizing hormone-releasing hormone (LRH) may be a critical physiologic mechanism regulating the occurrence of ovulation in many species. These studies were conducted to assess (1) the effects of intramuscular injections of LRH in the intact female rhesus monkey and (2) the effects of estradiol in a Silastic delivery system in ovariectomized female rhesus monkeys. No changes in blood levels of luteinizing hormone (LH) were detected in response to 200 micrograms of LRH. Ovulation did not occur 48 hours after treatment. Ovariectomy decreased estradiol, increased LH, and had no effect on prolactin concentrations in sera. Insertion of a vaginal ring containing 10% estradiol increased blood estradiol levels 100-fold. Serum prolactin levels were unaffected; however, LH concentrations were altered in a multiphasic fashion. After the ring had been in place for 15 days, vaginal blood similar to menstrual flow was observed following removal.

Animals↗