Luteal Stage Research Articles

Quantification of dynamic changes to blood volume and vascular flow in the primate corpus luteum during the menstrual cycle.

The objective of the current study was to determine changes to vascular parameters of nonhuman primate dominant ovarian structures by dynamic contrast-enhanced ultrasound (DCE-US). Dynamic contrast-enhanced ultrasound with intravenous microbubble infusion was performed on the rhesus macaque ovary bearing the pre-ovulatory follicle and corpus luteum (CL) sequentially during the natural luteal phase (n = 8) and GnRH antagonist (antide)-induced luteal regression (n = 6). Changes in luteal blood volume (BV) and vascular flow (VF) were observed between stages of the luteal phase Luteal BV was highest in early stage CL, before decreasing 2.5-fold in late stage CL (P < 0.06); in contrast, luteal VF peaked at mid luteal stage (P < 0.01). Two females identified with luteal insufficiency trended toward lower peak BV, compared to typical CLs. Another female was identified with a luteal cyst on the contralateral ovary, and a CL that regressed before P levels declined. After 72 hours of antide exposure, BV was reduced 2.3-fold (P = 0.03). DCE-US provides a sensitive, non-invasive measurement of the dynamics of blood volume and flow in dominant ovarian structures.

The effect of leptin on luteal angiogenic factors during the luteal phase of the estrous cycle in goats

Fibroblast growth factor 2 (FGF2), angiopoietin 1 (Ang1), and vascular endothelial growth factor (VEGF) are angiogenic factors implicated in the vascular development of the corpus luteum (CL). Each factor is regulated or influenced by leptin in non-ovarian tissues. Moreover, leptin and its receptor, ObRb, have been identified in luteal tissue throughout the luteal phase. Therefore, leptin is hypothesized to influence luteal vasculature through the regulation of FGF2, Ang1, and VEGF. Multiparous, cycling crossbred female goats (does) were allocated to early (n=12), mid (n=8), and late (n=11) stages of the luteal phase for CL collection. Luteal tissue was harvested and either snap frozen in liquid N2, paraffin embedded, or cultured with leptin (0, 10−12, 10−11, 10−10, 10−9, 10−8M). Tissue was analyzed for FGF2, Ang1, VEGF, ObRb, and leptin expression. Angiopoietin 1, FGF2, VEGF expression was higher (P≤0.001) in the mid-luteal stage than the early stage. Expression decreased (P≤0.001) during the late luteal stage with the exception of VEGF, which remained elevated. In contrast, leptin and ObRb were lowest (P≤0.003) during the mid-luteal stage compared to the early and late stages. All factors were detected in and/or around vessels in early stage tissue compared to mid and late stages. Leptin stimulated (P≤0.02) Ang1, FGF2, and VEGF expression only in early stage luteal cultures. Collectively, these data provide evidence that leptin may be involved in the luteal angiogenic process during the early stage of CL formation.

Galectin-3 contributes to luteolysis by binding to Beta 1 integrin in the bovine corpus luteum.

Luteolysis is characterized by a reduction in progesterone (P4) production and tissue degeneration in the corpus luteum (CL). One of major events during luteolysis is luteal cell death. Galectin-3, a ubiquitously expressed protein involved in many cellular processes, serves as an antiapoptotic and/or proapoptotic factor in various cell types. Although galectin-3 is detected in the bovine CL, its role remains unclear. The expression of galectin-3 in the bovine CL was higher at the regressed stage than at the other luteal stages. Galectin-3 was localized on luteal steroidogenic cells (LSCs). When cultured LSCs were exposed to prostaglandin F2alpha (PGF) for 48 h, the expression and secretion of galectin-3 increased. When the cultured LSCs were treated with galectin-3 for 24 h, cleaved caspase-3 expression was increased, and the cell viability was decreased, whereas P4 production did not change. Beta 1 integrin, a target protein of galectin-3, was expressed in bovine CL and possessed glycans, which galectin-3 binds. Furthermore, galectin-3 bound to glycans of luteal beta 1 integrin. The decreased cell viability of cultured LSCs by galectin-3 was suppressed by beta 1 integrin antibody. The overall findings suggest that the secreted galectin-3 stimulated by PGF plays a role in structural luteolysis by binding to beta 1 integrin.

Differential Expression of RFamide‐Related Peptide, a Mammalian Gonadotrophin‐Inhibitory Hormone Orthologue, and Kisspeptin in the Hypothalamus of Abadeh Ecotype Does During Breeding and Anoestrous Seasons

Gonadotrophin-inhibitory hormone (GnIH) is a novel hypothalamic neuropeptide that was discovered in birds as an inhibitory factor for gonadotrophin release. RFamide-related peptide (RFRP) is a mammalian GnIH orthologue that inhibits gonadotrophin synthesis and release in mammals through actions on gonadotrophin-releasing hormone (GnRH) neurones and gonadotrophs, mediated via the GnIH receptor (GnIH-R), GPR147. On the other hand, hypothalamic kisspeptin provokes the release of GnRH from the hypothalamus. The present study aimed to compare the expression of RFRP in the dorsomedial hypothalamus and paraventricular nucleus (DMH/PVN) and that of kisspeptin in the arcuate nucleus (ARC) of the female goat hypothalamus during anoestrous and breeding seasons. Mature female Abadeh does were used during anoestrus, as well as the follicular and luteal phases of the cycle. The number of RFRP-immunoreactive (-IR) neurones in the follicular phase was lower than in the luteal and anoestrous stages. Irrespective of the ovarian stage, the number of RFRP-IR neurones in the rostral and middle regions of the DMH/PVN was higher than in the caudal region. By contrast, the number of kisspeptin-IR neurones in the follicular stage was greater than in the luteal stage and during the anoestrous stage. Irrespective of the stage of the ovarian cycle, the number of kisspeptin-IR neurones in the caudal region of the ARC was greater than in the middle and rostral regions. In conclusion, RFRP-IR cells were more abundant in the rostral region of the DMH/PVN nuclei of the hypothalamus, with a greater number being found during the luteal and anoestrous stages compared to the follicular stage. On the other hand, kisspeptin-IR neurones were more abundant in the caudal part of the ARC, with a greater number recorded in the follicular stage compared to the luteal and anoestrous stages.

Lymphatic Involvement in the Disappearance of Steroidogenic Cells from the Corpus Luteum during Luteolysis

In mammals, the corpus luteum (CL) is an essential endocrine gland for the establishment and maintenance of pregnancy. If pregnancy is not established, the CL regresses and disappears rapidly from the ovary. A possible explanation for the rapid disappearance of the CL is that luteal cells are transported from the ovary via lymphatic vessels. Here, we report the presence of cells positive for 3β-hydroxysteroid dehydrogenase (3β-HSD), an enzyme involved in progesterone synthesis, in the lumen of lymphatic vessels at the regressing luteal stage and in the lymphatic fluid collected from the ovarian pedicle ipsilateral to the regressing CL. The 3β-HSD positive cells were alive and contained lipid droplets. The 3β-HSD positive cells in the lymphatic fluid were most abundant at days 22–24 after ovulation. These findings show that live steroidogenic cells are in the lymphatic vessels drained from the CL. The outflow of steroidogenic cells starts at the regressing luteal stage and continues after next ovulation. The overall findings suggest that the complete disappearance of the CL during luteolysis is involved in the outflow of luteal cells from the CL via ovarian lymphatic vessels.

In Vivo Chronic and In Vitro Acute Effects of Di(2-Ethylhexyl) Phthalate on Pseudopregnant Rabbit Corpora Lutea: Possible Involvement of Peroxisome Proliferator-Activated Receptor Gamma1

The in vivo chronic and in vitro acute effects of di(2-ethylhexyl) phthalate (DEHP) on the reproductive function of peroxisome proliferator-activated receptor gamma (PPARG) were studied in rabbit corpora lutea (CL) at early stage (Day 4), midstage (Day 9), and late stage (Day 13) of pseudopregnancy. The rabbits were in vivo treated with DEHP for 15 days before induction of pseudopregnancy. Immunohistochemistry provided evidence for the presence of PPARG, prostaglandin endoperoxide synthase 1 (PTGS1), PTGS2, prostaglandin E2-9-ketoreductase (PGE2-9-K), and 3beta-hydroxysteroid dehydrogenase (3beta-HSD) in all the luteal cells during pseudopregnancy. DEHP decreased progesterone plasma levels and CL production in all the luteal stages and PPARG protein and gene expressions in early and mid-CL. DEHP in vivo treatment reduced PTGS2 protein expression at the late stage and that of PGE2-9-K at all the stages, whereas PTGS1 and 3beta-HSD were not affected. In in vitro cultured CL, DEHP alone, the PPARG antagonist T0070907 alone, or DEHP plus T0070907 diminished progesterone production and 3beta-HSD activity and increased PGF2alpha and PTGS2 in early and mid-CL, whereas DEHP plus the PPARG agonist 15d-PGJ2 did not affect these hormones and enzymes. All the in vitro treatments did not affect PGE2 secretion as well as PTGS1 and PGE2-9-K enzymatic activities in all the luteal stages. These results provided evidence that DEHP favors functional luteolysis of pseudopregnant rabbit CL, with a mechanism that seems to involve PPARG expression down-regulation, an increase of PTGS2 activity and prostaglandin F2alpha secretion, 3beta-HSD down-regulation, and decrease in progesterone.

The effects of LH on progesterone production by cell subpopulations isolated from early and late luteal phase goat corpora lutea

The objective of this study was to investigate the complementary effects of luteinizing hormone (LH) on cell subpopulations. Corpora lutea were collected on days 5 and 15 of the cycle. The luteal tissues were treated with collagenase for cell dissociation. Percoll density-gradient centrifugation was performed to separate cells into 2 distinct subpopulations. Luteal cells (5 × 104 cells/well) were cultured with and without 22(R)-hydroxycholesterol (22R-HC, 10 µg/mL) and LH (10 and 100 ng/mL) alone, and also with 22R-HC (10 µg/mL) plus LH (10 and 100 ng/mL), in a serum-free culture medium for 6 days of incubation. Untreated cells isolated from luteal tissue collected on day 15 of the estrous cycle produced more steroids than those collected on day 5. Treatment of the cells with LH resulted in a significant (P < 0.05) increase in steroid synthesis on both days 5 and 15 of the cycle. Throughout the 7 days of incubation, 22R-HC caused a significant increase in progesterone production compared to untreated controls and to the LH treatments (P < 0.01). As a result, it appears that LH is mainly effective on small luteal cells in both the early and late luteal stages in goats.

Histochemical study of river buffalo’s uterine endometrium in follicular and luteal phases

Summary This study was conducted to evaluate histochemical alterations of river buffalo’s uterine wall acid and alkaline phosphatases (ALP and ACP), lipase and carbohydrate ratio during follicular and luteal phases. Forty apparently healthy and non pregnant river buffalos were considered for removal of the uterus after sacrifice in slaughterhouse. All dissected uteri were divided into two luteal (by observing corpus luteum on the ovary) and follicular phase (by identifying growing follicles) specimens. In order to prepare frozen section slides, the fresh samples of uterus were transferred into chilled normal saline and cut with cryostat. ALP, ACP, lipase and periodic acid-schiff (PAS) staining techniques (paraffin sections) were conducted. Endometrial epithelium, glandular cells, vascular endothelium and macrophages in luteal phase showed positive reaction to both phosphatases. Comparing the luteal and follicular phases showed that, the mentioned cells presented significantly higher reaction to both phosphatases in luteal stage. The number of endometrial macrophages increased in luteal phase. The cytoplasmic carbohydrate ratio of endometrial epithelium and glands were significantly higher in follicular phase. Reactions to PAS staining revealed that, the glandular cells showed remarkably denser PAS stained cytoplasm in comparison to epithelial and endothelial cells. In luteal phase, uterus represented higher lipase ratio in comparison to follicular phase. In conclusion, similar to other bovine and buffalo species, in river buffalos the histochemical alterations in endometrial phosphatases, carbohydrates (mainly glycogen) and lipase depend on cyclic hormonal changes.

Proliferation of Luteal Steroidogenic Cells in Cattle

The rapid growth of the corpus luteum (CL) after ovulation is believed to be mainly due to an increase in the size of luteal cells (hypertrophy) rather than an increase in their number. However, the relationship between luteal growth and the proliferation of luteal steroidogenic cells (LSCs) is not fully understood. One goal of the present study was to determine whether LSCs proliferate during CL growth. A second goal was to determine whether luteinizing hormone (LH), which is known have roles in the proliferation and differentiation of follicular cells, also affects the proliferation of LSCs. Ki-67 (a cell proliferation marker) was expressed during the early, developing and mid luteal stages and some Ki-67-positive cells co-expressed HSD3B (a steroidogenic marker). DNA content in LSCs isolated from the developing CL increased much more rapidly (indicating rapid growth) than did DNA content in LSCs isolated from the mid CL. The cell cycle-progressive genes CCND2 (cyclin D2) and CCNE1 (cyclin E1) mRNA were expressed more strongly in the small luteal cells than in the large luteal cells. LH decreased the rate of increase of DNA in LSCs isolated from the mid luteal stage but not in LSCs from the developing stage. LH suppressed CCND2 expression in LSCs from the mid luteal stage but not from the developing luteal stage. Furthermore, LH receptor (LHCGR) mRNA expression was higher at the mid luteal stage than at the developing luteal stage. The overall results suggest that the growth of the bovine CL is due to not only hypertrophy of LSCs but also an increase in their number, and that the proliferative ability of luteal steroidogenic cells decreases between the developing and mid luteal stages.

Short oestrous cycles in sheep during anoestrus involve defects in progesterone biosynthesis and luteal neovascularisation

Anoestrous ewes can be induced to ovulate by the socio-sexual, 'ram effect'. However, in some ewes, the induced ovulation is followed by an abnormally short luteal phase causing a so-called 'short cycle'. The defect responsible for this luteal dysfunction has not been identified. In this study, we investigated ovarian and uterine factors implicated in male-induced short cycles in anoestrous ewes using a combined endocrine and molecular strategy. Before ovulation, we were able to detect a moderate loss of thecal expression of steroid acute regulatory protein (STAR) in ewes that had not received progesterone priming (which prevents short cycles). At and following ovulation, we were able to identify a significant loss of expression of genes coding key proteins involved in the biosynthesis of progesterone (STAR, CYP11A1 and HSD3B1 (HSD3B)) as well as genes coding proteins critical for vascular development during early luteal development (VEGFA and KDR (VEGFR2)), suggesting dysfunction in at least two pathways critical for normal luteal function. Furthermore, these changes were associated with a significant reduction of progesterone production and luteal weight. Additionally, we cast doubt on the proposed uterus-mediated effect of prostaglandin F2α (PGF2α) as a cause of short cycles by demonstrating the dysregulation of luteal expression of the PGF receptor, which mediates the luteal effects of PGF2α, and by finding no significant changes in the circulating concentrations of PGFM, the principal metabolite of PGF2α in ewes with short cycles. This study is the first of its kind to examine concurrently the endocrine and molecular events in the follicular and early luteal stages of the short cycle.

Evidence for local neuroendocrine signaling in ovarian prolactin regulation

s / Journal of Equine Veterinary Science 34 (2014) 108 108 winter or during the luteal phase. PRLr were richly distributed throughout luteal tissue of both summer and winter cycling ovaries. Luteal PRLr distributionwas uniform within the CL and did not vary between luteal stages. PRLr were also present in oocytes from all follicle stages and was detected in the ovulation fossa. No other ovarian structures contained PRLr IR product.

Upregulation of TLR-4 and proinflammatory cytokine transcripts as diagnostic indicator of endometritis in buffaloes

The aim of present study was to examine the relative mRNA transcription of toll-like receptor 4 (TLR-4), CD14, interleukin-1β (IL-1β), interleukin-8 (IL-8), and tumor necrosis factor alpha (TNF-α) in endometritic buffaloes. Reproductive tracts were collected from 60 buffaloes at postmortem. The genitalia were diagnosed for endometritis based on positive white side test of uterine fluid, presence of >5% polymorphonuclear cells in uterine cytology, and endometrial histopathology. The endometritis-positive genitalia were categorized as luteal (n = 10) and follicular (n = 10) based on the presence of corpus luteum. Further, 20 normal genitalia (luteal, n = 10 and follicular, n = 10) were also included as control. The endometrial tissue scrapings were collected ex vivo from all the samples, total RNA was extracted, complementary DNA was transcribed for each sample, and relative quantification of mRNA was done by real-time polymerase chain reaction. The threshold cycle values of all the samples were normalized with the housekeeping β-actin gene and relative fold change was calculated using 2−ΔΔCt method. Present study revealed a variable upregulation of TLR-4, CD14, IL-1β, IL-8, and TNF-α transcription in endometritic buffaloes either at luteal or follicular stage. Predominantly at luteal stage, the significant upregulation of TLR-4, IL-8, and TNF-α transcripts was 4.66-, 21.19-, and 42.49-fold, respectively, indicated the possibility of cytokine-based diagnostic method for the early indication of endometritis before the onset of cyclic estrus. Nevertheless, further research in respect to threshold level of each cytokine in uterine biopsies involving more number of animals is required to establish a potential marker gene(s) for the diagnosis of endometritis and for devising novel therapeutic intervention.

The effects of EGF and IGF-1 on FSH-mediated in vitro maturation of domestic cat oocytes derived from follicular and luteal stages

The objective of this study was to evaluate the influence of epidermal growth factor (EGF) and insulin like growth factor-I (IGF-1) on the in vitro maturation of cat oocytes recovered from follicular and luteal stage ovaries. Oocytes from follicular (n=580) and luteal (n=209) stages were harvested and divided into four groups, which were cultured in FSH-mediated maturation medium supplemented with: (1) EGF alone (25ng/mL); (2) IGF-1 alone (100ng/mL); (3) EGF+IGF-1 (25ng/mL EGF+100ng/mL IGF-I); or (4) no growth factor (control). The proportion of follicular stage oocytes reaching the metaphase II stage was significantly higher than that of oocytes obtained at the luteal stage in both control and study groups (p<0.001). The percentages of oocytes reaching the metaphase II stage during the follicular period were 62.6% in control; 70.9% in EGF; 72.8% in IGF-1, and 78.1% in EGF+IGF-1 groups, whereas the respective values for gametes collected from luteal stage ovaries were 12.5%, 17.5%, 12.5%, and 16.9%. Additionally, the differences between the study and control groups were significant in the case of follicular stage oocytes. Finally, supplementing the maturation medium with EGF and/or IGF-1 significantly enhanced the meiotic maturation of oocytes recovered from follicular stage ovaries. The present study also demonstrated that the combination of EGF and IGF-I provides an additional or synergic effect on meiotic maturation of oocytes recovered from the follicular stage.

Unfolding protein response signaling is involved in development, maintenance, and regression of the corpus luteum during the bovine estrous cycle

The corpus luteum (CL) is a transient endocrine organ. Development, maintenance, and regression of CL are effectively controlled by dynamic changes in gene expression. However, it is unknown what types of gene are affected during the CL life span of the estrous cycle in bovine. Here, we determined whether unfolded protein response (UPR) signaling via eIF2α/ATF4/GADD34, p90ATF6/p50ATF6, and IRE1/XBP1, which is a cellular stress response associated with the endoplasmic reticulum (ER), is involved in the bovine CL life span. Our results indicated that expression of Grp78/Bip, the master UPR regulator, was increased during the maintenance stage and rapidly decreased at the regression stage. Additionally, UPR signaling pathways genes were found to be involved in luteal phase progression during the estrous cycle. Our findings suggested that Grp78/Bip, ATF6, and XBP1 act as ER chaperones for initiating CL development and maintaining the CL. In addition, we investigated whether ER stress-mediated apoptosis is occurred through three UPR signaling pathways in CL regression stage. Interestingly, pIRE1 and CHOP were found to be involved in both the adaptive response and ER stress-mediated apoptosis. During the CL regression stage, increased expression of pJNK and CHOP, two components of ER stress-mediated apoptotic cascades, occurred before increased level of cleaved caspase 3 were observed. The present investigation was performed to identify a functional link between UPR signaling and CL life span during the bovine estrous cycle. Taken together, results from this study demonstrated that UPR protein/gene expression levels were different at various stages of the bovine CL life span. Variations in the expression of these protein/genes may play important roles in luteal stage progression during the estrous cycle.

Remodeling of bovine endometrium throughout the estrous cycle

The mammalian endometrium changes morphologically and functionally throughout the estrous cycle. In some species, endometrial cells also undergo periodic proliferation and degeneration. However, the remodeling of bovine endometrium throughout the estrous cycle remains unclear. In the present study, we examined how the remodeling of bovine endometrium varied through the estrous cycle by measuring the relative rates of cell proliferation and apoptosis. Cells positive for both KI-67 (a proliferation marker) and cleaved caspase-3 (CCP3: an apoptotic cell marker) were immunohistochemically evaluated throughout the estrous cycle in the luminal and glandular epithelia, and the stroma of bovine endometrium. Percentages of KI-67-positive cells tended to be higher at the early luteal and follicular stages than at the mid and late luteal stages in all cell types. Similarly, percentages of CCP3-positive cells were higher at the early luteal stage than at the mid and late luteal stages in the luminal epithelium and stroma. Furthermore, CCP3 expression levels by Western blot analysis agreed with these immunohistological observations. On the other hand, DNA fragmentation was detected in the bovine endometrium without significant differences during the estrous cycle by the terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) method. Together, these results show that cell proliferation and apoptosis undergo cyclic patterns in the bovine endometrium, and suggest that the bovine endometrium is remodeled in each estrous cycle.

Variation in the stress response between high- and low-neuroticism female undergraduates across the menstrual cycle

This study was undertaken to elucidate possible relationships between menstrual cycle stage, neuroticism and behavioral and physiological responses to a cognitive challenge. The study investigated the differences between high neuroticism and low neuroticism groups across the menstrual cycle (luteal, menstrual and ovulatory stages). The Stroop color-naming task was used as a stressor. During the task, the galvanic skin response (GSR), heart rate (HR) and HR variability (HRV) were simultaneously recorded by a polygraph. The results showed a significant difference in reaction times (RT) on the Stroop task between the high- and low-neuroticism groups during menstruation. However, there were no significant RT differences between groups during the luteal or ovulatory cycle stages. The GSR of the high-neuroticism group during menstruation was significantly lower than it was in the luteal and ovulatory stages. Moreover, during menstruation, the cardiovascular responses (high-frequency HRV (HF) and low-frequency HRV (LF)) and accuracy on the Stroop task were positively correlated, while the correlations between HF, LF and the RT were negative. The results demonstrate that during menstruation, there were consistent variations in female behavior and physiology when facing a cognitive stressor. Specifically, the high-neuroticism group was more sensitive to the stressor than the low neuroticism group, with decreased reaction time on the Stroop task, and increased GSR and HRV.

Evidence for a Luteotropic Role of Peroxisome Proliferator-Activated Receptor Gamma: Expression and In Vitro Effects on Enzymatic and Hormonal Activities in Corpora Lutea of Pseudopregnant Rabbits1

The expression of peroxisome proliferator-activated receptor gamma (PPARgamma) and its role in corpora lutea (CL) function were studied in pseudopregnant rabbits. Corpora lutea were collected at an early stage (Day 4), midstage (Day 9), and late stage (Day 13) of pseudopregnancy. Immunohistochemistry found evidence for the presence of PPARgamma in the perinuclear cytoplasm and nucleus of all the luteal cells; immunoreactivity decreased from the early to the late stage, with immunonegativity of the nuclei of late stage CL. PPARgamma mRNA transcript was expressed in all the luteal stages with the lowest level in the late stage. In CL cultured in vitro, the PPARgamma agonist (15-deoxy delta12,14 prostaglandin J2 [15d-PGJ2], 200 nM) increased and the antagonist (T0070907, 50 nM) decreased progesterone secretion at early and midluteal stages, whereas 15d-PGJ2 reduced and T0070907 increased PGF2alpha at the same stages. Prostaglandin-endoperoxide synthase 2 (PTGS2) activity was reduced by 15d-PGJ2 and increased by T0070907 in CL of early and midluteal stages. Conversely, 15d-PGJ2 increased and T0070907 reduced 3beta-hydroxysteroid dehydrogenase (3beta-HSD) activity in early and midluteal stage CL. PGE2 in vitro secretion as well as PTGS1 and 20alpha-HSD enzymatic activities were not affected by 15d-PGJ2 and T0070907 in any CL types. These results indicate that PPARgamma plays a luteotropic role in pseudopregnant rabbits, through PTGS2 down-regulation and 3beta-HSD up-regulation, with a consequent PGF2alpha decrease and progesterone increase.

Aglepristone (RU534) effects on luteal function of pseudopregnant rabbits: Steroid receptors, enzymatic activities, and hormone productions in corpus luteum and uterus

The study was designed to examine the aglepristone (RU534) mechanisms affecting the corpora lutea (CL) lifespan in pseudopregnant rabbits. Aglepristone (10mg/kg b.w.) was injected subcutaneously twice at either early- or mid-luteal phase (Days 3 and 4, or Days 8 and 9, respectively) after induction of ovulation with GnRH (Day 0). Corpora lutea and uteri, explanted at days 6 and 11, were evaluated for immunohistochemistry and Western blotting of progesterone (PR) and estrogen (ER) receptors, cyclooxygenase 1 (COX1), COX2, and PGE2-9-ketoreductase (PGE2-9-K) enzymatic activities, and progesterone, PGF2α, and PGE2 in vitro synthesis. Independent of luteal stage, aglepristone prolonged the functional luteal phase by 3 Days over that of controls as assessed by blood progesterone profiles. Aglepristone decreased protein for ER during both luteal-stages in CL and uteri. Progesterone receptor protein was decreased by RU354 at Days 6 in the uterus and at Days 11 in CL, whereas RU534 increased PR at Days 11 in uteri. In the CL, RU534 enhanced progesterone production at Days 6 and 11, whereas it decreased PGF2α and increased PGE2 at Day 11. In the uteri, RU534 decreased PGF2α and increased PGE2 synthesis at both days. COX2 and PGE2-9K activities were decreased by RU534 in the CL at Day 11, whereas in the uteri COX2 increased and PGE2-9-K decreased at Days 6 and 11. In conclusion, these data on aglepristone effects suggest that progesterone has a regulatory role on luteal function through direct and uterine-mediated mechanisms in pseudopregnant rabbits.

Neuroendocrine disorders in women with epilepsy depending on anticonvulsants intake

Aim. To assess the influence of epilepsy and anticonvulsants on central control of hormone release and ovarian function in women of reproductive age. Methods. The reproductive and endocrine functions were assessed in 82 female patients with epilepsy, of whom 37 did not receive anticonvulsants (first group), 45 patients were on anticonvulsant treatment (second group). 17 healthy females (control group) were also assessed. Serum levels of estradiol, progesterone, prolactin, luteinizing hormone, follicle-stimulating hormone and dehydroepiandrosterone were estimated during follicular (n=48) and luteal (n=34) stages of menstrual cycle. Results. Estradiol serum level was below normal ranges, and prolactin serum level - above normal limits at follicular stage of menstrual cycle in female patients not treated with anticonvulsants. In luteal phase serum levels of estradiol, progesterone, dehydroepiandrosterone exceeded the reference ranges, and testosterone levels were lower than normal in both patients treated and not treated with anticonvulsants. Comparison of two groups showed that estradiol serum level was lower in untreated patients in both stages of menstrual cycle compared to patients treated with anticonvulsants. There was a marked difference in endocrine function at all levels of reproductive neuroendocrine regulation in untreated female patients compared to female patients treated with anticonvulsants with major transformations in female patients with epilepsy not treated with anticonvulsants. Conclision. Epilepsy and treatment with anticonvulsants can influence the central regulation of hormone release in females.

Topographic Distribution of the Different Cell Types, Connective Tissue and Vascular Tissue/Lumina Within a Functional Bovine Corpus Luteum and its Association with Breed, Type of Fixation Protocol and Stage During the Cycle

In the present study, we analysed the effect of fixative, breed, luteal stage and location on the nuclear density, volume density of connective tissue and vascular tissue/lumina within a bovine luteal gland in view of the development of an in vivo sampling technique to longitudinally monitor luteal histophysiology. The inner zone defined as the zone geometrically closest to the centre of the gland shows a significantly lower nuclear density (for all cell types) and a higher volume density of collagen fibres and vessels when compared with the outer zone (p<0.001). The nuclear density in luteal glands from Holstein-Friesian cows is not significantly different from that in Belgian Blue cows, nor is it in stage II vs stage III glands. The collagen fibre content was significantly lower in glands of Belgian Blue cows (p=0.01) and in younger glands (p=0.003). Hence, it seems that the lower nuclear density in the inner zone was compensated by a higher amount of collagen fibres. As the type of fixative applied has a significant effect on the nuclear density of the different cell types, the present study warrants future research to further optimize the fixation protocol. As a conclusion, we can state that the topographic difference in nuclear distribution for the different cell types in a bovine luteal gland is only significant when comparing the inner vs the outer zone. This implies that if a sample representative for the whole gland has to be taken, for example, when taking an in vivo sample, it is necessary that the biopsy goes through the inner zone and contains the total diameter of the gland.