Early Luteal Phase Research Articles

Is it essential to perform preoperative diagnostic curettage in patients scheduled for uterine myoma surgery?

<strong>Objective:</strong> Uterine myoma, which arises from the myometrium of uterus, is among the most common benign tumors of women. Generally, it has an asymptomatic character, however, in symptomatic cases, it presents with abnormal uterine bleeding. The objective of this study is to determine whether preoperative diagnostic curettage is essential or not by comparing the preoperative and postoperative endometriums of patients that underwent surgery with uterine myoma diagnosis. <strong>Material and Method</strong>: In this study,260 patients that received surgery with uterine myoma diagnosis in the Gynecology and Obstetrics Department of Taksim Education and Research Hospital in Istanbul between January 2007 and January 2010, were included. The histopathologic analysis of specimens obtained by preoperative curettage and hysterectomy, was carried out in a retrospective fashion. <strong>Results:</strong> The mean age of patients was 48.3 ± 7.5 years. The distribution of preoperative curettage specimens with regard to endometrial status was as follows: phase compatible endometrium in 156 (60%), endometrial polyp in 74 (28.5%), atrophic endometrium in 20 (7.7%), and endometrial hyperplasia in 10 patients (3.8%). Among the phase compatible endometriums, 85 patients (54.5%) had proliferative endometrium, 39 patients (25%) had late secretory phase endometrium, and 32 patients (20.5%) had early secretory phase endometrium. The distribution of postoperative hysterectomy specimens with regard to endometrial status was as follows: Phase compatible endometrium in 160 patients (61.5%), endometrial polyp in 61 patients (22.5%), endometrial hyperplasia in 14 patients (5.4%), and atrophic endometrium in 25 patients (9.6%). Among the phase compatible endometriums; 96 patients (60%) had proliferative endometrium, 44 patients (27.5%) had late secretory endometrium, and 20 patients (12.5%) had early secretory endometrium. <strong>Conclusion:</strong> No difference was observed between the histopathologic results of diagnostic curettage and hysterectomy relative to malignancy or a pathology that would change the surgery plan. The result is very important because it shows that performing curettage before myoma surgery is not an essential procedure. In this study, since endometrial cancer may not have been detected due to limited number of patients, further studies including higher number of patients are required to confirm our results.

P2.179 Exposure to Neisseria Gonorrhoeae (GC) During the Perimenstrual Period May Increase Risk of Infection in Female GC Contacts

Previous studies have shown that a woman is more likely to be diagnosed with gonococcal (GC) infection during the first five days of her menstrual cycle (active menstruation) than during...

Early luteal phase endocrine profile is affected by the mode of triggering final oocyte maturation and the luteal phase support used in recombinant follicle-stimulating hormone–gonadotropin-releasing hormone antagonist in vitro fertilization cycles

To assess endocrine differences during early luteal phase according to mode of triggering final oocyte maturation with or without luteal phase support (LPS). A prospective randomized study. University center for reproductive medicine. Four oocyte donors each underwent four consecutive cycles. To avoid interpatient variation, each donor underwent the same stimulation regimen. However, different modes of triggering final oocyte maturation and LPS were administered: A) 10,000 IU hCG and standard LPS; B) GnRH agonist (GnRHa; 0.2 mg triptorelin), and 35 hours later 1,500 IU hCG, and standard LPS; C) GnRH agonist (0.2 mg triptorelin) and standard LPS; and D) GnRH agonist (0.2 mg triptorelin) without LPS. Blood sampling was performed on the day of ovulation trigger, ovulation trigger + 1 day, and ovum pick-up + 5 days. Serum E2, FSH, LH, and P were measured. The early luteal phase steroid levels following GnRHa trigger and modified luteal phase support (B) were similar to those seen after hCG trigger (A). However, significant differences were seen between groups A and B compared with C and D, as well as between groups C and D. Administration of a single bolus of GnRHa effectively induced LH and FSH surges in oocyte donors stimulated with recombinant FSH and cotreated with a GnRH antagonist. However, gonadotropin and steroid levels differed significantly according to the type of luteal phase support used after GnRHa trigger. 2009-009429-26.

Uterine artery blood flow characteristics assessed during oestrus and the early luteal phase of pregnant and non-pregnant bitches

The aim of this study was to measure uterine artery blood velocity daily using Doppler ultrasonography in 10 young and 10 older clinically normal bitches throughout oestrus.Typical arterial waveforms identified in young bitches were characterised by a systolic peak and subsequent flow throughout diastole, whereas in older bitches, flow was sometimes absent in diastole. For 3days immediately prior to ovulation, at the time of declining plasma oestrogen and increasing progesterone concentrations, resistance index (RI) increased, principally associated with decreased diastolic velocity; in some bitches there was absent late diastolic flow during this time. In older bitches, the waveform appearance was more variable, with absent late and early diastolic flow observed in some cases. Mean RI was higher throughout oestrus for older bitches compared with young bitches, although both groups had a similar 3-day duration increase before ovulation. Nine of the young bitches and five of the older bitches became pregnant; litter size was smaller for the older bitches. Non-pregnant bitches: (1) were significantly older; (2) had fewer waveforms with continuous diastolic flow 2days before ovulation; (3) had lower end diastolic velocity, higher RI and fewer waveforms with continuous diastolic flow 2days after ovulation, and (4) had lower plasma progesterone concentrations 5days after ovulation. These are the first detailed observations of uterine artery blood velocity and waveform appearance throughout oestrus in bitches, and this is the first description of a link between impaired diastolic flow and reduced fertility. Assessment of uterine artery velocity could be useful to promote understanding of physiological mechanisms and could also become an important tool to assess potential infertility.

The progesterone receptor antagonist, onapristone has differential effects on the timing and control of the luteolytic mechanism depending on timing of administration in sheep

Cyclic ewes were treated with control vehicle or progesterone receptor antagonist (onapristone; 100mg i.m. twice daily) during either early (day 3–5) or late (day 12–14) luteal phase and plasma samples collected for hormone analysis and to determine endogenous and oxytocin induced PGF2α release. On day 14 and 17, ewes were euthanised and reproductive tracts collected for ovarian morphology and endometrium for oxytoxin and steroid hormone receptor analysis. Early treatment increased LH, but not progesterone or oestradiol, while late treatment elevated all three hormones. Early treatment delayed the up-regulation of endometrial oxytocin receptors and responsiveness to oxytocin challenge, delaying luteolysis. Late treatment advanced development of oxytocin receptors and responsiveness to oxytocin though not timing of luteolysis. Patterns of hormone receptor mRNA were differentially disrupted by treatments. Results provide mechanistic insight into hormonal control of the oestrous cycle and identify the ability of the luteolytic mechanism to dissociate from functional luteolysis.

Critical role of hyaluronidase-2 during preimplantation embryo development

Biological functions of hyaluronan (HA) depend on its molecular size. Small size HAs are known to regulate cell proliferation; however, the expression of HA synthases (HASs) and hyaluronidase-2 (HYAL2) and their role during early embryo development have not been previously identified. In this paper, we have shown by immunostaining that HA is produced by bovine in vitro-produced embryos at all stages of early development to blastocyst. Addition of HA-synthesis inhibitor (4-methylumbelliferone; 4MU) to in vitro embryo culture inhibited blastocyst formation. HASs HAS2 and HAS3 mRNA were expressed at all stages of embryo development; however, relative mRNA expression of HAS2 was significantly reduced as the embryos develop to the blastocyst stage. HAS1 was detected during 2- and 4-cell stages but was barely detectable in subsequent stages. HYAL2 mRNA expression was detected in oviducts at the early luteal phase but was only detected in the embryos at morula and blastocyst stages (Day 6 and 7 post-fertilization). Addition of HYAL2 to embryo culture media at Day 2 post-fertilization increased phosphorylated mitogen-activated protein kinases (MAPK1 and 3) in the embryos and improved development to the blastocyst stage and increased embryo cell numbers. Addition of an anti-CD44 antibody or an MAPK inhibitor (U0126) abrogated the positive effects of HYAL2 on blastocyst rates. In conclusion, we demonstrate that the expression of different HAS genes and HYAL2 in bovine embryos varies according to the stage of development and that the supplementation of HYAL2 in vitro mimics oviductal conditions and is shown to improve the blastocyst rate and embryo quality, an effect which requires CD44 activity and MAPK signalling.

Expression of adiponectin receptors 1 (AdipoR1) and 2 (AdipoR2) in the porcine pituitary during the oestrous cycle

BackgroundAdiponectin, protein secreted mainly by white adipose tissue, is an important factor linking the regulation of metabolic homeostasis and reproductive processes. The biological activity of the hormone is mediated via two distinct receptors, termed adiponectin receptor 1(AdipoR1) and adiponectin receptor 2 (AdipoR2). The present study analyzed mRNA and protein expression of AdipoR1 and AdipoR2 in the anterior (AP) and posterior (NP) pituitary of cyclic pigs.MethodsThe total of 20 animals was assigned to one of four experimental groups (n = 5 per group) as follows: days 2–3 (early-luteal phase), 10–12 (mid-luteal phase), 14–16 (late-luteal phase), 17–19 (follicular phase) of the oestrous cycle. mRNA and protein expression were analyzed using real-time PCR and Western Blot methods, respectively.ResultsThe lowest AdipoR1 gene expression was detected in AP on days 10–12 relative to days 2–3 and 14–16 (p < 0.05). In NP, AdipoR1 mRNA levels were elevated on days 10–12 and 14–16 (p < 0.05). AdipoR2 gene expression in AP was the lowest on days 10–12, and an expression peak occurred on days 2–3 (p < 0.05). In NP, the lowest (p < 0.05) expression of AdipoR2 mRNA was noted on days 17–19. The AdipoR1 protein content in AP was the lowest on days 17–19 (p < 0.05), while in NP the variations in protein expression levels during the oestrous cycle were negligible. AdipoR2 protein in AP was most abundant on days 10–12, and it reached the lowest level on days 2–3 and 17–19 of the cycle (p < 0.05). The presence of AdipoR2 protein in NP was more pronounced on days 10–12 (p < 0.05).ConclusionsOur study was the first experiment to demonstrate that AdipoR1 and AdipoR2 mRNAs and proteins are present in the porcine pituitary and that adiponectin receptors expression is dependent on endocrine status of the animals.

Influence of mineral supplementation on oxidative stress, ovarian follicles growth and reproductive hormone concentration in cyclic Arab mares

To study the effect of minerals supplementation in improving brood mare antioxidant status, ovarian activity and some reproductive hormone profiles. Five Arab broodmares were supplemented with multi-minerals in their drinking water for three months (Treated) and five control mares received the same ration with no mineral (control) belonging to Police Academy horse stud. All mares were subjected to ovarian ultrasonography and blood sampling at weekly intervals during mineral supplementation. Leptin, estradiol, progesterone and insulin like growth factor-1 were assayed with radioimmunoassay. Mineral concentrations in blood serum were determined using atomic absorption spectrometer. Nitric oxide, lysozymes, total antioxidant capacity and lipid peroxide were also measured. Diameter of the first large follicle (Dominant) and the second large follicle (Subordinate) was higher in treated mares during both estrous and early luteal phases. Moreover diameter of corpus luteum was higher in treated mares compared to control. Mineral supplementation decreased significantly ( P =0.004) levels of leptin but insignificantly improved insulin like growth factor-1 in treated mares. Levels of progesterone, estradiol were insignificantly lower in treated mares. There was a significant increase in levels of lysozymes ( P =0.0001) and total antioxidants ( P <0.006) but a significant decrease in lipid peroxide ( P <0.0001) in treated mares. Nitric oxide did not change greatly by mineral supplementation. Zinc ( P =0.004), copper ( P =0.009), Iron ( P =0.001), cobalt ( P =0.004) and magnesium ( P =0.03) levels were significantly higher in treated mares. Mineral supplementation improved the animals' oxidant antioxidant balance, reproductive hormones and ovarian cyclicity and their supplementation is recommended before any breeding programs.

Effects of regular aerobic exercise on post-exercise vagal reactivation in young female

Regular aerobic exercise accelerates post-exercise cardiovagal reactivation. However, little is known about the potentially favourable modulatory effects of regular aerobic exercise on cardiovagal reactivation in young female. The purpose of this study was to examine effects of regular aerobic exercise on post-exercise vagal reactivation in young female. Our study consisted of 8 female endurance-trained athletes (athlete group) and 10 untrained females (control group). Resting heart rate (HR), HR variability and post-exercise cardiovagal reactivation were measured during the subjects’ early follicular (EF) and middle luteal (ML) phases. Post-exercise cardiovagal reactivation was estimated by T30: the time constant of HR decline for the first 30 s after the 4-min cycle ergometer exercise (intensity: 80% of ventilation threshold). In both groups, T30 was more accelerated in the EF phase than in the ML phase (P<0.05). In the EF phase, T30 was lower in the athletes than in the controls (P<0.05). A significant correlation between maximum oxygen uptake (O2max) and T30 was observed in the EF phase (r=0.545, P<0.05). Our results suggest that regular aerobic exercise accelerates post-exercise cardiovagal reactivation in the EF phase in young female.

Emergency Contraception

There have been numerous attempts to control fertility after unprotected sexual intercourse (UPSI). From very bizarre methods like the vaginal application of Coca Cola to the more serious attempts using calcium antagonists influencing fertility parameters in sperm to hormonal methods or intrauterine devices. So far, hormonal methods preventing or delaying ovulation have proved to be the most popular starting with the combination of ethinyl estradiol and levonorgestrel (LNG), known as the Yuzpe regimen. The first dose had to be taken within 72 hours of UPSI, a second one 12 hours later. Later on, LNG alone, at first in a regimen similar to the Yuzpe method (2 × 0.75 mg 12 hours apart) showed to be more successful, eventually resulting in the development of a 1.5 mg LNG pill that combined good efficacy with a high ease of use. Several efficacious and easy to use methods for emergency contraception (EC) are available on the market today with the most widely spread being LNG in a single dose of 1.5 mg (given as one tablet of 1.5 mg or 2 tablets of 0.75 mg each) for administration up to 3 days (according to WHO up to 5 days) after UPSI. Its limitations are the non-optimal efficacy which is decreasing the later the drug is taken and the fact that it is only approved for up to 72 hours after UPSI. This regimen has no effect on the endometrium, corpus luteum function and implantation, is not abortive and don't harm the fetus if accidentally taken in early pregnancy. It has no impact on the rate of ectopic pregnancies. It has become the standard method used up to this day in most countries. Since the mid 1970s copper IUDs have been used for EC, which show a high efficacy. Their disadvantages lie in the fact that EC is considered an off label use for most IUDs (not for the GynFix copper IUD in the European Union) and that they might not be acceptable for every patient. Furthermore IUD-insertion is an invasive procedure and it is required trained providers and sterilized facilities. Mifepristone in the dosages of 10 or 25 mg is used with good results as an emergency contraceptive in China for up to 120 hours after UPSI, but has never received any significant consideration in Western countries. While high doses of mifepristone has an effect on endometrial receptivity and will inhibit ovulation if given in the follicular phase and prevent implantation if given in the early luteal phase, low doses such as 10 mg has no impact on the endometrium. Mifepristone does not increase the rate of ectopic pregnancies. The most recent development is the approval of the selective progesterone receptor modulator ulipristal acetate (UPA) in the dosage of 30 mg for EC up to 5 days after UPSI, combining the safe and easy application of the single dose LNG pill with an even higher efficacy. It has shown to be more efficacious than LNG and can be used for up to 120 hours after UPSI; the difference in efficacy is highest for 0–24 hours, followed by 0–72 hours following UPSI. No VTE has been reported following UPA-administration or any progesterone receptor modulator. No effect on endometrium, corpus luteum function and implantation has been observed with doses used for EC. Independent of the substance it should be noted that, if there is a choice, the intake of an oral emergency contraceptive pill should happen as soon as possible after the risk situation. A preexsisting pregnancy must be excluded. Possible contraindications and drug interactions must be considered according to the individual special product informations.

Leucocyte phagocytosis during the luteal phase in bitches

Pyometra is a disease that affects a large proportion of intact bitches, and typically is seen during the latter half of dioestrus. Several factors contribute to the development of pyometra, including genetic factors, an infectious component (most often Escherichia coli), and hormonal factors. Hormones may act directly on the endometrium, and also affect the immune system. In dogs, the phagocytic ability has been shown to decrease with age, and ovarian hormones have also been shown to affect immune resistance. The aim of the present study was to examine whether phagocytosis by canine leucocytes varies significantly during the luteal phase. Eight bitches were followed by repeated blood sampling. Samples were taken at the calculated optimal day for mating (Day 1), and thereafter on days 8, 15 and 22 (early luteal phase) and 29, 43, 57 and 71 (late luteal phase). Blood was collected from the cephalic vein into EDTA tubes for leucocyte counts and heparinised tubes for testing of phagocytosis and oxidative burst using commercial kits and flow cytometry. The cell activity of the phagocyting leucocytes, expressed as mean fluorescence activity, MFI, was significantly lower during late luteal phase than during early luteal phase. The proportion of leucocytes that was induced to phagocyte did not differ significantly. The percentage of cells stimulated by E. coli to oxidative burst was significantly lower during late luteal phase. Their activity did not differ between the two periods. The number of cells stimulated to oxidative burst by a low stimulus was too low to evaluate, and leucocytes stimulated with the high stimulus did not vary in oxidative burst between the two periods. The changes in phagocytic activity and in the number of leucocytes that showed oxidative burst were not associated with any change in the proportion of different leucocytes. The decreased phagocytic capacity possibly contributes to the higher incidence of diseases such as pyometra during the latter part of the luteal phase.

Effects of systemic progesterone during the early luteal phase on the availabilities of amino acids and glucose in the bovine uterine lumen

The uterine histotroph provides essential nutrition to the developing conceptus during the preimplantation period of pregnancy. The objective of the present study was to examine the effects of cycle stage and progesterone (P4) concentrations in the blood on the recoverable quantities of amino acids and glucose in the histotroph during the preimplantaion period of conceptus development. Following oestrus, dairy heifers were assigned to low, control or high P4 groups (n=6 heifers per treatment and time point). The uterine horn ipsilateral to the corpus luteum was flushed on either Day 7 or Day 13. The present study quantified 24 amino acids and glucose in the uterine flushings using HPLC and fluorometry, respectively. Heifers in the low P4 group had lower plasma concentrations of P4 throughout the cycle, whereas heifers in the high group had higher plasma concentrations of P4 between Days 3 and 7 compared with the control group (P<0.05). Total recoverable neutral (Ser, Gln, Gly, Thr, Cit, β-Ala, Tau, Ala, Tyr, Trp, Met, Val, Phe, Ile, Leu, Pro and Cys), acidic (Glu) and basic (His, Arg, Orn and Lys) amino acids were greater (P<0.05) on Day 13 than on Day 7. There was no significant difference in the amount of Asp or Asn between Day 7 and Day 13. The amount of amino acids recovered on Day 7 was similar across treatment groups. On Day 13, the amount of Asn, His and Thr was lower (P<0.05) in the low P4 heifers compared with the controls and/or high P4 heifers. Quantities of glucose were not altered by cycle stage or P4 treatment. In conclusion, the stage of oestrous cycle and P4 play important roles in modulating amino acids in the histotroph, a potentially critical factor for early embryonic and/or conceptus survival.

Prostaglandin E2 functions as a luteotrophic factor in the dog

The luteal phase in dogs is governed by many poorly understood regulatory mechanisms. Functioning of the corpus luteum (CL) is unaffected by hysterectomy. Recently, the role of prostaglandins in regulating canine CL function was addressed suggesting a luteotrophic effect of prostaglandin E2 (PGE2) during the early luteal phase. However, compelling functional evidence was lacking. The potential of PGE2 to stimulate steroidogenesis was tested in canine primary luteal cells isolated from developing CL of non-pregnant dogs. In addition, the luteal expression of prostaglandin transporter (PGT) and steroidogenic acute regulatory protein (STAR) was demonstrated and characterized in CL from non-pregnant bitches during the course of dioestrus as well as from pregnant animals during the pre-implantation, post-implantation and mid-gestation periods of pregnancy and during luteolysis; the luteal expression of PGE2 receptors (EP2 and EP4) has been investigated at the protein level throughout pregnancy. Our findings show that PGE2 is an activator of STAR expression in canine luteal cells from early luteal phase, significantly up-regulating STAR promoter activity and protein expression resulting in increased steroidogenesis. The 3βHSD (HSD3B2) and P450scc (CYP11A1) expression remained unaffected by PGE2 treatment. The expression of PGT was confirmed in CL during both pregnancy and dioestrus and generally localized to the luteal cells. After initial up-regulation during the earlier stages of the CL phase, its expression declined towards the luteal regression. Together with the demonstration of EP2 and EP4 throughout pregnancy, and the decline in EP2 at prepartum, our findings further support our hypothesis that intra-luteal PGE2 may play an important role in regulating progesterone secretion in the canine CL.

Co-Orelation of Histological Dating and Glycogen Content by Histochemical Stain during Various Phases of Menstrual Cycle in Primary Infertility

Glycogen and its products of metabolism are considered to be the most important and direct source of nutrient for the early conceptus. The premenstrual biopsies were taken from 100 women with primary infertility whose male partners had normal semenograms. The biopsies were then subjected to Haematoxylin and Eosin (H & E) and Periodic Acid Schiff (PAS) staining with and without diastase to study histological and histochemical changes particularly glycogen content in the endometrium respectively. Histolomorphologic spectrum of endometrium on H & E stained sections revealed early proliferative phase (4%), late proliferative phase (7%) and early secretory phase (7%), mid secretory phase (33%) and late secretory phase (49%). PAS staining with or without diastase for glycogen was performed and glycogen content, as demonstrated by magenta color, was graded from + to ++++. Glycogen content was observed to be “+” to “++” in proliferative phase, where as in secretory phase, it varied from “++” to “+++”. Glycogen was confirmed by treatment with diastase enzyme, after that PAS stain gave negative staining, i.e. loss of magenta color as glycogen was digested by diastase. Glycogen deficiency was observed in 24.7% of secretory phase endometrium of infertile women. Depletion of glycogen results in inadequate preparation of endometrium at the time of implantation, and hence, may be one of the causes of infertility.

Gene expression of adiponectin receptors: 1 (Adipor1) and 2 (Adipor2) in the porcine ovary during the oestrous cycle

Background: Adiponectin, protein secreted mainly by white adipose tissue, is an important factor linking the regulation of metabolic homeostasis and reproductive processes. The biological activity of the hormone is mediated via two distinct receptors, termed adiponectin receptor 1(AdipoR1) and adiponectin receptor 2 (AdipoR2). The present study analyzed mRNA and protein expression of AdipoR1 and AdipoR2 in the anterior (AP) and posterior (NP) pituitary of cyclic pigs. Methods: The total of 20 animals was assigned to one of four experimental groups (n = 5 per group) as follows: days 2–3 (early-luteal phase), 10–12 (mid-luteal phase), 14–16 (late-luteal phase), 17–19 (follicular phase) of the oestrous cycle. mRNA and protein expression were analyzed using real-time PCR and Western Blot methods, respectively. Results: The lowest AdipoR1 gene expression was detected in AP on days 10–12 relative to days 2– 3a nd 14–16 (p< 0.05). In NP, AdipoR1 mRNA levels were elevated on days 10–12 and 14–16 (p< 0.05). AdipoR2 gene expression in AP was the lowest on days 10–12, and an expression peak occurred on days 2–3 (p<0.05). In NP, the lowest (p<0.05) expression of AdipoR2 mRNA was noted on days 17–19. The AdipoR1 protein content in AP was the lowest on days 17–19 (p< 0.05), while in NP the variations in protein expression levels during the oestrous cycle were negligible. AdipoR2 protein in AP was most abundant on days 10–12, and it reached the lowest level on days 2–3 and 17–19 of the cycle (p< 0.05). The presence of AdipoR2 protein in NP was more pronounced on days 10–12 (p<0.05). Conclusions: Our study was the first experiment to demonstrate that AdipoR1 and AdipoR2 mRNAs and proteins are present in the porcine pituitary and that adiponectin receptors expression is dependent on endocrine status of the animals.

110 EFFECT OF HUMAN CHORIONIC GONADOTROPIN (hCG) ADMINISTRATION ON DAYS 1, 2, 3, OR 4 POST-OESTRUS ON CORPUS LUTEUM DEVELOPMENT AND CIRCULATING PROGESTERONE CONCENTRATIONS IN BEEF HEIFERS

The steroid hormone progesterone (P4) plays a key role in the reproductive events associated with the establishment and maintenance of pregnancy. Elevated concentrations of circulating P4 in the immediate post-conception period have been associated with advanced conceptus elongation, increased interferon-tau production, and greater pregnancy rates in cattle. Several strategies have been employed to supplement the endogenous P4 supplied by the corpus luteum (CL). One such strategy is the administration of human chorionic gonadotropin (hCG) during the early luteal phase (typically Day 5) that induces ovulation of the first wave dominant follicle and formation of a functional accessory CL, in turn leading to increased circulating concentrations of P4. In addition to this effect, hCG also stimulates hypertrophy of the original CL, leading to a significant deviation in P4 concentrations 2 days after administration. The aim of this study was to examine whether administration of hCG earlier during the metoestrus period would lead to an earlier rise in P4 by stimulation of the developing endogenous CL. The oestrous cycles of cross-bred beef heifers (n = 50) were synchronised and those recorded in standing oestrus (Day 0) were assigned randomly to one of 5 treatments and administered a single IM injection of saline on Day 1 after oestrus (Control) or 3000 IU hCG on Day 1, 2, 3, or 4 after oestrus. Daily blood samples were collected from Day 0 to 14 by coccygeal venipuncture to measure serum P4 concentration. The dimensions of the original CL and induced CL, when present, were measured by daily ultrasound scanning beginning on Day 3 after oestrus until Day 14. Data were analysed using the PROC MIXED procedure of SAS (SAS Institute Inc., Cary, NC, USA). In terms of effects on the CL, administration of hCG on Day 1 had no effect on CL area. Administration on Day 2 increased CL area from Day 6 to 12 (P ≤ 0.05). hCG on Day 3 increased CL area from Day 9 to 11, while administration on Day 4 increased CL size on Day 9 and 10 (P ≤ 0.05). Administration of hCG on Day 4 induced the formation of an accessory CL in 89% of heifers, resulting in a significant increase in total luteal tissue area on the ovaries compared to all other groups. Consistent with the effects on the CL, hCG on Day 1 did not affect P4 concentrations. Administration on Day 2 significantly increased P4 compared to the control from Day 6 to 11 (P ≤ 0.05). Administration on Day 3 resulted in a nonsignificant increase in P4, while hCG on Day 4 increased P4 from Day 8 to 13 compared to the control (P ≤ 0.05). In conclusion, administration of hCG as early as Day 2 post oestrus results in increased P4 in circulation from Day 6 which should have beneficial downstream effects in terms of uterine receptivity and conceptus elongation. Funded by Science Foundation Ireland (07/SRC/B1156) and the Spanish Ministry of Science and Innovation AGL2009-11810.

Exploration of Global Gene Expression Changes During the Estrous Cycle in Equine Endometrium1

The equine endometrium exhibits characteristic morphological and functional changes during the estrous cycle controlled by the interplay of progesterone and estradiol. A microarray analysis of endometrial tissue samples derived from five time points of the estrous cycle (Day [D] 0, D3, D8, D12, and D16) was performed to study the dynamics of equine endometrial gene expression. Statistical analysis revealed 4996 genes differentially expressed during the estrous cycle. Clustering of similar expression profiles was performed to find groups of coregulated genes. This revealed eight major profiles: highest mRNA concentrations on D0, from D0 to D3, on D3, from D3 to D8, on D8, from D8 to D12, from D12 to D16, and on D16. Bioinformatics analysis revealed distinct molecular functions and biological processes for the individual expression profiles characterizing the different phases of the estrous cycle (e.g., extracellular matrix and inflammatory response during the estrus phase, cell division and cell cycle during early luteal phase, and endoplasmic reticulum, protein transport, and lipid metabolism in the luteal phase). A comparison to dynamic gene expression changes in bovine endometrium identified common and species-specific gene regulations in cyclic endometrium. Analysis of expression changes during the estrous cycle for genes previously found to be differentially expressed on D12 of pregnancy provided new evidence for possible regulation of these genes. This study provides new insights regarding global changes of equine endometrial gene expression as molecular reflections of physiological changes in the cyclic equine endometrium with regard to the crucial role of this tissue for successful reproduction.

Endocrine and Molecular Control of Luteal and Placental Function in Dogs: A Review

In the domestic dog (Canis familiaris), the corpus luteum (CL) is the only source of progesterone (P4) in non-pregnant and pregnant animals. The progesterone secretion profiles are almost identical in both conditions until the last third of the luteal phase when the gradual P4 decline turns into a steep drop in pregnant bitches, indicating the onset of parturition. Consequently, the length of the CL-phase in non-pregnant dogs exceeds the luteal lifespan in pregnant animals. The canine CL-function is regulated by many species-specific regulatory mechanisms, the most intriguing of which is the reported independence of gonadotropic support during the first third of dioestrus. Recently, PGE2 has been proposed as one of the most important luteotropic factors acting locally during this time, but afterwards prolactin (PRL) appears to be the main luteotropic factor. Luteal regression/luteolysis occurs, however, in spite of an increased gonadotropic support. Lately, by demonstrating the expression of PRL-receptor (PRLr), a new insight into possible regulatory mechanisms has indicated that the supply of P4 could be controlled upstream of the steroidogenic machinery at the level of PRLr expression and/or function, subsequently leading to the functional suppression of the steroidogenic machinery. An endogenous source of a luteolytic agent is apparently lacking, implicating the luteal regression in non-pregnant bitches as a passive, degenerative process even if the PGF2α-receptor is constitutively expressed in canine CL. This is in contrast to pregnant dogs in which prepartum luteolysis seems to be an active process of CL destruction by PGF2α of utero/placental origin targeting the luteal PGF2α-receptor.

Molecular aspects of mucin biosynthesis and mucus formation in the bovine cervix during the periestrous period

Mucus within the cervical canal represents a hormonally regulated barrier that reconciles the need to exclude the vaginal microflora from the uterus during progesterone dominance, while permitting sperm transport at estrus. Its characteristics change during the estrous cycle to facilitate these competing functional requirements. Hydrated mucin glycoproteins synthesized by the endocervical epithelium form the molecular scaffold of this mucus. This study uses the bovine cervix as a model to examine functional groups of genes related to mucin biosynthesis and mucus production over the periestrous period when functional changes in cervical barrier function are most prominent. Cervical tissue samples were collected from 30 estrus synchronized beef heifers. Animals were slaughtered in groups starting 12 h after the withdrawal of intravaginal progesterone releasing devices (controlled internal drug releases) until 7 days postonset of estrus (luteal phase). Subsequent groupings represented proestrus, early estrus, late estrus, metestrus, and finally the early luteal phase. Tissues were submitted to next generation RNA-seq transcriptome analysis. We identified 114 genes associated with biosynthesis and intracellular transport of mucins, and postsecretory modifications of cervical; 53 of these genes showed at least a twofold change in one or more experimental group in relation to onset of estrus, and the differences between groups were significant (P < 0.05). The majority of these genes showed the greatest alteration in their expression in the 48 h postestrus and luteal phase groups.

Effect of cytokines and ovarian steroids on equine endometrial function: an in vitro study

Regulation of immune-endocrine interactions in the equine endometrium is not fully understood. The aims of the present study were to: (1) investigate the presence of tumour necrosis factor alpha (TNF), interferon gamma (IFNG), Fas ligand (FASLG) and their receptors in the mare endometrium throughout the oestrous cycle; and (2) assess endometrial secretory function (prostaglandins), angiogenic activity and cell viability in response to TNF, oestradiol (E2), progesterone (P4) and oxytocin (OXT). Transcription of TNF and FASLG mRNA increased during the early and late luteal phase (LP), whereas IFNG mRNA increased in late LP. Transcription of the mRNA of both TNF receptors was highest in the mid-LP. All cytokines and receptors were expressed in surface and glandular epithelium, as well as in the stroma. Expression of TNF and its receptor TNFRSF1A increased during the follicular phase (FP) and mid-LP. IFNG was expressed in the mid-LP, whereas its receptor IFNR1 was expressed in the in mid- and late LP. The highest expression of FASLG and FAS occurred during the late LP. OXT increased the secretion of prostaglandin (PG) E2 and PGF2α in the FP and mid-LP. In the mid-LP, E2 and P4+E2 stimulated PGF2α secretion, whereas TNF and P4 increased cell viability. All treatments, with the exception of P4, increased nitric oxide and angiogenic activity in both phases. The coordinated action of cytokines and ovarian hormones may regulate secretory, angiogenic and proliferative functions in the equine endometrium.