PHB regulates meiotic recombination via JAK2-mediated histone modifications in spermatogenesis.

Previously, we have shown that human sperm Prohibitin (PHB) expression is significantly negatively correlated with mitochondrial ROS levels but positively correlated with mitochondrial membrane potential and motility. However, the possible role of PHB in mammalian spermatogenesis has not been investigated. Here we document the presence of PHB in spermatocytes and its functional roles in meiosis by generating the first male germ cell-specific Phb-cKO mouse. Loss of PHB in spermatocytes resulted in complete male infertility, associated with not only meiotic pachytene arrest with accompanying apoptosis, but also apoptosis resulting from mitochondrial morphology and function impairment. Our mechanistic studies show that PHB in spermatocytes regulates the expression of STAG3, a key component of the meiotic cohesin complex, via a non-canonical JAK/STAT pathway, and consequently promotes meiotic DSB repair and homologous recombination. Furthermore, the PHB/JAK2 axis was found as a novel mechanism in the maintenance of stabilization of meiotic STAG3 cohesin complex and the modulation of heterochromatin formation in spermatocytes during meiosis. The observed JAK2-mediated epigenetic changes in histone modifications, reflected in a reduction of histone 3 tyrosine 41 phosphorylation (H3Y41ph) and a retention of H3K9me3 at the Stag3 locus, could be responsible for Stag3 dysregulation in spermatocytes with the loss of PHB.

Prohibitin involvement in the generation of mitochondrial superoxide at complex I in human sperm.

Prohibitin (PHB), a major mitochondrial membrane protein, has been shown earlier in our laboratoryto regulate sperm motility via an alteration in mitochondrial membrane potential (MMP) in infertile men with poor sperm quality. To test if PHB expression is associated with sperm mitochondrial superoxide (mROS) levels, here we examined sperm mROS levels, high MMP and lipid peroxidation in infertile men with poor sperm motility (asthenospermia, A) and/or low sperm concentrations (oligoasthenospermia, OA). The diaphorase-type activity of sperm mitochondrial complex I (MCI) and PHB expression were also determined. We demonstrate that mROS and lipid peroxidation levels are significantly higher in sperm from A and OA subjects than in normospermic subjects, whereas high MMP and PHB expression are significantly lower. A positive correlation between mROS and lipid peroxidation and a negative correlation of mROS with PHB expression, high MMP, and sperm motility were found in these subjects. The finding of similar diaphorase-type activity levels of sperm MCI in the three groups studied suggests that the catalytic subunits of MCI in the matrix arm may produce mROS on its own. There may be a dysfunction of electron transport at MCI associated with decreased expression of PHB in sperm with poor quality. We conclude that mROS level is increased and associated with decreased PHB expression, and it may regulate sperm motility via increases in low MMP and lipid peroxidation. This is the first report on the involvement of PHB in human sperm motility loss associated with increased generation of mROS at MCI.

Effects of adrenomedullin on the expression of inflammatory cytokines and chemokines in oviducts from women with tubal ectopic pregnancy: an in-vitro experimental study.

BACKGROUND: The occurrence of tubal ectopic pregnancy (tEP) is related to the inflammation of the oviduct. Recently, Adrenomedullin (ADM) was found highly expression in human oviduct. The current study is to investigate whether ADM have a modulatory action on inflammatory cytokines and chemokines in oviductal tissue from women with tubal ectopic pregnancy (tEP). METHODS: Oviductal isthmus samples were collected from women with tEP undergoing salpingectomy, and women undergoing hysterectomy for benign gynaecological conditions. The mRNA and protein levels of inflammatory cytokines/chemokines were assayed by PCR (n = 6 for tEP, n = 5 for controls) and protein microarray methods (n = 5 for both tEP and controls) respectively. RESULTS: Some of the inflammatory cytokines/chemokines were upregulated by ADM in oviducts from tEP patients at both mRNA and protein levels. Incubation of oviduct from tEP patients with ADM for 24 h down-regulated some of these cytokines/chemokines. CONCLUSION: Our results suggest an additional mechanism whereby ADM insufficiency may increase the susceptibility to tEP through diminished anti-inflammatory activity. The actual impact of the relationship between ADM and inflammatory process on tubal implantation needs further exploration.

The ubiquitin specific protease USP34 promotes ubiquitin signaling at DNA double-strand breaks.

Ubiquitylation plays key roles in DNA damage signal transduction. The current model envisions that lysine63-linked ubiquitin chains, via the concerted action of E3 ubiquitin ligases RNF8-RNF168, are built at DNA double-strand breaks (DSBs) to effectively assemble DNA damage-repair factors for proper checkpoint control and DNA repair. We found that RNF168 is a short-lived protein that is stabilized by the deubiquitylating enzyme USP34 in response to DNA damage. In the absence of USP34, RNF168 is rapidly degraded, resulting in attenuated DSB-associated ubiquitylation, defective recruitment of BRCA1 and 53BP1 and compromised cell survival after ionizing radiation. We propose that USP34 promotes a feed-forward loop to enforce ubiquitin signaling at DSBs and highlight critical roles of ubiquitin dynamics in genome stability maintenance.

Ulipristal acetate resembles mifepristone in modulating human fallopian tube function.

STUDY QUESTION: Do ulipristal acetate (UPA) and mifepristone have an effect on ciliary beat frequency and muscular contractions in the human Fallopian tube? SUMMARY ANSWER: UPA, in resemblance to mifepristone, inhibits ciliary beat and muscular contraction of the human Fallopian tube, probably through an agonistic effect on the tubal progesterone receptor. WHAT IS KNOWN ALREADY: UPA, like mifepristone, acts as an emergency contraceptive mainly by inhibiting ovulation. Little is known about its effects on tubal function. STUDY DESIGN, SIZE, DURATION: This was an in vitro experimental study using Fallopian tube samples collected from 11 women undergoing hysterectomy for benign non-tubal gynaecological conditions. PARTICIPANTS/MATERIALS, SETTING, METHODS: The tubal epithelium and longitudinal smooth muscle fibres were isolated, cultured and treated with UPA at graded concentrations of 0, 20, 200 and 2000 ng/ml, and mifepristone at graded concentrations of 0, 300, 3000 and 30 000 ng/ml, respectively. After treatment, ciliary beat frequency was determined using a photometric method. Basal tone, amplitude and frequency of muscular contraction were recorded through a force transducer. The mRNA expression of progesterone receptor (total and PR-B isoform), glycodelin and adrenomedullin were determined by real-time quantitative PCR. MAIN RESULTS AND THE ROLE OF CHANCE: There was an overall dose-dependent suppressive effect on ciliary beat frequency (P < 0.0001) after treatment with UPA at all concentrations and with mifepristone at 3000 ng/ml or above. The basal tone, amplitude and frequency of muscular contractions were significantly reduced (P < 0.05) after treatment with UPA at 200 ng/ml or above, and with mifepristone at 3000 ng/ml or above. UPA treatment at 200 ng/ml or above significantly up-regulated the mRNA expression of progesterone receptor and glycodelin and down-regulated the mRNA expression of adrenomedullin in Fallopian tube tissue (P < 0.05). LIMITATIONS, REASONS FOR CAUTION: Whether or not the tubal effect may translate into additional mechanisms for contraceptive action in vivo is uncertain. WIDER IMPLICATIONS OF THE FINDINGS: The clinical relevance of UPA with regard to contraceptive activity is worthy of further exploration. STUDY FUNDING/COMPETING INTERESTS: The study was supported by a Seed Fund from the Centre of Reproduction, Development and Growth, Faculty of Medicine, the University of Hong Kong. All authors have no competing interest to declare.

Intermedin in rat uterus: changes in gene expression and peptide levels across the estrous cycle and its effects on uterine contraction.

BACKGROUND: The present study demonstrates the expression of intermedin (IMD) and its receptor components in the uterus of the female rat during the estrous cycle and its effect on uterine contraction. METHODS: The gene expression level of intermedin and its receptor components and the peptide level of intermedin were studied by real-time RT-PCR and enzyme immunoassay (EIA) respectively. The separation of precursor and mature IMD was studied by gel filtration chromatography and EIA. The localization of IMD in the uterus was investigated by immunohistochemistry. The effect of IMD on in vitro uterine contraction was studied by organ bath technique. RESULTS: Uterine mRNAs of Imd and its receptor components and IMD levels displayed cyclic changes across the estrous cycle. Imd mRNA level was the highest at proestrus while the IMD level was the highest at diestrus. IMD was found in the luminal and glandular epithelia and IMD treatment significantly reduced the amplitude and frequency of uterine contraction but not the basal tone. Both calcitonin gene-related peptide (CGRP) receptor antagonist hCGRP8-37 and adrenomedullin (ADM) receptor antagonist hADM22-52 partially abolished the inhibitory effect of IMD on uterine contraction while the specific IMD receptor antagonist hIMD17-47 completely blocked the actions. The enzyme inhibitors of NO (L-NAME) and PI3K (Wortmannin) pathways diminished the IMD effects on uterine contraction while the cAMP/PKA blocker, KT5720, had no effect, indicating an involvement of NO and PI3K/Akt but not PKA. CONCLUSIONS: IMD and the gene expression of its receptor components are differentially regulated in the uterus during the estrous cycle and IMD inhibits uterine contraction by decreasing the amplitude and frequency.

Adrenomedullin in rat follicles and corpora lutea: expression, functions and interaction with endothelin-1.

BACKGROUND: Adrenomedullin (ADM), a novel vasorelaxant peptide, was found in human/rat ovaries. The present study investigated the interaction of ADM and endothelin-1 (ET-1) in follicles and newly formed corpora lutea (CL) and the actions of ADM on progesterone production in CL during pregnancy. METHODS: The peptide and gene expression level of adrenomedullin in small antral follicles, large antral follicles and CL was studied by real-time RT-PCR and EIA. The effect of ADM treatment on oestradiol production in 5-day follicular culture and on progesterone production from CL of different pregnant stages was measured by EIA. The interaction of ADM and ET-1 in follicles and CL at their gene expression level was studied by real-time RT-PCR. RESULTS: In the rat ovary, the gene expression of Adm increased during development from small antral follicles to large antral follicles and CL. In vitro treatment of preantral follicular culture for 5 days with ADM increased oestradiol production but did not affect follicular growth or ovulation rate. The regulation of progesterone production by ADM in CL in culture was pregnancy-stage dependent, inhibitory at early and late pregnancy but stimulatory at mid-pregnancy, which might contribute to the high progesterone production rate of the CL at mid-pregnancy. Moreover, the interaction between ADM and ET-1 at both the production and functional levels indicates that these two vasoactive peptides may form an important local, fine-tuning regulatory system together with LH and prolactin for progesterone production in rat CL. CONCLUSIONS: As the CL is the major source of progesterone production even after the formation of placenta in rats, ADM may be an important regulator in progesterone production to meet the requirement of pregnancy.

Coexpression of adrenomedullin and its receptor component proteins in the reproductive system of the rat during gestation.

BACKGROUND: Adrenomedullin (ADM), a novel vasorelaxant peptide, was found in human/rat ovaries and uteri. Plasma ADM level increases in pregnant women and pregnant rats. METHODS: The gene expression levels of Adm and its receptor components - Crlr, Ramp1, Ramp2 and Ramp3, the ADM peptide concentration and localization in the rat female reproductive system during gestation were studied by real-time RT-PCR, EIA and immunohistochemical techniques. RESULTS: The mRNAs of Adm and its receptor component and ADM were differentially distributed between implantation sites and inter-implantation sites of the pregnant uterus. The day on which vaginal sperm were found was taken to be pregnancy day 1. The Adm mRNA levels in the implantation sites of the uteri in mid- (day 12) and late pregnancy (day 17) were more than 10-fold higher than those in nonpregnancy, pre-implantation (day 3) or early (day 7) pregnancy. ADM was localized in the endometrial stroma with increased immunoreactivity from nonpregnancy to pregnancy. The ADM level and the mRNA levels of Adm, Crlr, Ramp2 and Ramp3 in the corpus luteum all increased in late pregnancy compared with early pregnancy. The gene expression of Adm and it receptor components and intense immunostaining of ADM were also found in the oviduct during pregnancy. CONCLUSIONS: The gene expressions levels of Adm and its receptor components - Crlr, Ramp1, Ramp2 and Ramp3, and ADM peptide concentration exhibited a spatio-temporal pattern in the rat female reproductive system during gestation and this suggests that ADM may play important roles in gestation.

Prohibitin (PHB) interacts with AKT in mitochondria to coordinately modulate sperm motility.

Prohibitin (PHB), an evolutionarily conserved mitochondrial inner membrane protein, is highly expressed in cells that require strong mitochondrial function. Recently, we demonstrated that the deletion of Phb in spermatocytes results in impaired mitochondrial function. In addition, PHB expression in the mitochondrial sheath of human sperm has a significantly negative correlation with mitochondrial reactive oxygen species levels, but a positive one with mitochondrial membrane potential and sperm motility. These results suggest that mitochondrial PHB expression plays a role in sperm motility. However, the mechanism of PHB-mediated regulation of sperm motility remains unknown. Here, we demonstrate for the first time that PHB interacts with protein kinase B (AKT) and exists in a complex with phospho-PHB (pT258) and phospho-AKT in the mitochondrial sheath of murine sperm, as determined using colocalization and coimmunoprecipitation assays. After blocking AKT activity using wortmannin (a phosphatidylinositol 3-kinase [PI3K] inhibitor), murine sperm have significantly ( P < 0.05) decreased levels of phospho-PHB (pT258) and the total and progressive motility. Furthermore, significantly ( P < 0.05) lower levels of phospho-PI3K P85 subunit α+γ (pY199 and pY467) and phospho-AKT (pS473; pT308) are found in sperm from infertile asthenospermic and oligoasthenospermic men compared with normospermic subjects, which suggest a reduced activity of the PI3K/AKT pathway in these infertile subjects. Importantly, these sperm from infertile subjects also have a significantly ( P < 0.05) lower level of phospho-PHB (pT258). Collectively, our findings suggest that the interaction of PHB with AKT in the mitochondrial sheath is critical for sperm motility, where PHB phosphorylation (pT258) level and PI3K/AKT activity are key regulatory factors.

Adrenomedullin insufficiency alters macrophage activities in fallopian tube: a pathophysiologic explanation of tubal ectopic pregnancy.

Ectopic pregnancy is the major cause of maternal morbidity and mortality in the first trimester of pregnancy. Tubal ectopic pregnancy (TEP) accounts for nearly 98% of all ectopic pregnancies. TEP is usually associated with salpingitis but the underlying mechanism in salpingitis leading to TEP remains unclear. Adrenomedullin (ADM) is a peptide hormone abundantly expressed in the fallopian tube with potent anti-inflammatory activities. Its expression peaks at the early luteal phase when the developing embryo is being transported through the fallopian tube. In the present study, we demonstrated reduced expression of ADM in fallopian tubes of patients with salpingitis and TEP. Using macrophages isolated from the fallopian tubes of these women, our data revealed that the salpingistis-associated ADM reduction contributed to aggravated pro-inflammatory responses of the tubal macrophages resulting in production of pro-inflammatory and pro-implantation cytokines IL-6 and IL-8. These cytokines activated the expression of implantation-associated molecules and Wnt signaling pathway predisposing the tubal epithelium to an adhesive and receptive state for embryo implantation. In conclusion, this study provided evidence for the role of ADM in the pathogenesis of TEP through regulating the functions of tubal macrophages.

Growth-differentiation factor-8 (GDF-8) in the uterus: its identification and functional significance in the golden hamster.

Transforming growth factor-beta superfamily regulates many aspects of reproduction in the female. We identified a novel member of this family, growth-differentiation factor 8 (GDF-8) in the 72 h post coital uterine fluid of the golden hamster by proteomic techniques. Uterine GDF-8 mRNA decreased as pregnancy progressed while its active protein peaked at 72 h post coitus (hpc) and thereafter stayed at a lower level. At 72 hpc, the GDF-8 transcript was localized to the endometrial epithelium while its protein accumulated in the stroma. Exogenous GDF-8 slowed down proliferation of primary cultures of uterine smooth muscle cells (SMC) and endometrial epithelial cells (EEC). In addition, GDF-8 attenuated the release of LIF (leukaemia inhibiting factor) by EEC. As for the embryo in culture, GDF-8 promoted proliferation of the trophotoderm (TM) and hatching but discouraged attachment. Our study suggests that GDF-8 could regulate the behavior of preimplantation embryos and fine-tune the physiology of uterine environment during pregnancy.

Effect of aging on the expression of adrenomedullin and its receptor component proteins in the male reproductive system of the rat.

This study investigated the levels of adrenomedullin (AM) and the gene expression of AM, calcitonin receptor-like receptor (CRLR), receptor activity-modifying proteins (RAMPs), and receptor-coupling protein (RCP) in the testis, ventral prostate, seminal vesicle, and epididymis in rats aged 3, 12, and 20 months by radioimmunoassay and semiquantitative reverse transcription-polymerase chain reaction (RT-PCR). The results indicate an age-related increase in AM and its messenger RNA (mRNA) levels in the testis and decrease in the sex accessory glands. The gene expression of CRLR and RCP decreased only in the sex accessory glands. The changes in the gene expression of RAMPs suggest that the major increase was in CGRP receptors in the testis, whereas the major decreases in the ventral prostate and the seminal vesicles might be CGRP and AM receptors, respectively. The decreases in these receptors were similar in the epididymis. The results suggest possible roles of AM in the male reproductive system during aging.

Differential regulation of adrenomedullin gene expression in the fundic and pyloric regions of the rat stomach during acute and chronic starvation.

Adrenomedullin (AM) has been shown to be present in the stomach but the role of gastric AM is obscure. To investigate the effects of starvation on AM in the stomach, we studied the changes in gene expression of preproadrenomedullin (preproAM) and AM receptors by reverse transcription-polymerase chain reaction (RT-PCR), and tissue AM concentrations by radioimmunoassay (RIA) in the fundus and pylorus of the stomach of rats subjected to either acute (1-day) or chronic (4-day) starvation. An up-regulation of preproAM gene expression was observed in the fundus after acute starvation, and in the pylorus after chronic starvation. Immunoreactive AM (ir-AM) levels were increased in both fundus and pylorus after chronic starvation. In addition, marked reductions in the gene expression of fundic calcitonin receptor-like receptor (CRLR) and receptor activity-modifying protein (RAMP) 3 as well as the pyloric CRLR and RAMP2 were observed in the chronically starved rats. The present study suggests that the gene expression of preproadrenomedullin mRNA is differentially regulated by starvation in the different parts of the stomach.

Male genital tract antioxidant enzymes--their ability to preserve sperm DNA integrity.

Male germ cells are unique because they lose a bulk of their cytoplasm as cytoplasmic droplets when they develop, leading to a decrease in endogenous antioxidant and hence a dependence on extracellular antioxidant system to overcome oxidative stress. Spermatozoa are particularly vulnerable to oxidative stress because their plasma membrane is rich in polyunsaturated fatty acids and membrane-bound NADPH oxidase. To protect spermatozoa from oxidative attack, an optimal amount of reactive oxygen species is maintained by balancing the reactive oxygen species generated during sperm maturation in the epididymidis and antioxidants in secretions of the male reproductive tract. The male accessory sex glands secretions have been shown to be the major source of antioxidant enzymes in the ejaculate and have the important function of preserving sperm DNA integrity from oxidative stress experienced in the uterine environment. In our in vivo golden hamster model, ablation of the five major male accessory sex glands, namely the ampullary glands, coagulating glands, dorsolateral prostate, ventral prostate and seminal vesicle, was found to cause higher incidence and greater degree of DNA damage in spermatozoa. These damaged sperm are able to undergo fertilization at the same rate as intact ones; however, the outcome of embryos sired is seriously affected.

Cycle-to-cycle variation in utero-ovarian hemodynamic indices in ovarian stimulation and natural cycles of the same women and its effect on the outcome of assisted reproduction treatment.

OBJECTIVE: To investigate the blood flow parameters between cycles of the same women to assess whether parameters predicting a successful pregnancy in a stimulation cycle could be used to determine the outcome of subsequent natural cycles. DESIGN: A prospective study. SETTING: Assisted reproduction unit, the University of Hong Kong. PATIENT(S): Fifty-eight IVF cycles and 40 natural cycles were evaluated. INTERVENTION(S): Assessments of the utero-ovarian pulsatility indices (PIs), resistance indices (RIs), and endometrial color signals. RESULT(S): In IVF cycles, the pregnancy rate (27%) was similar to that in frozen-thawed embryo transfer (FET) (28%) cycles. The utero-ovarian PIs and RIs in IVF cycles were significantly lower than those in the natural cycles. There was a significant correlation between the uterine PI in stimulation cycles and that in natural cycles. In IVF cycles, the pregnancy rate declined significantly when the uterine PI was >2.70 and the RI was >0.9. In FET cycles, no decline in pregnancy rate was seen. Conceptional FET cycles showed significantly higher uterine PI, uterine RI, and endometrial color signals compared with conceptional IVF cycles. CONCLUSION(S): Hemodynamic parameters in stimulation cycles are different from those in natural cycles, and the values of various parameters in predicting pregnancy are also different.

Male genital tract antioxidant enzymes: their source, function in the female, and ability to preserve sperm DNA integrity in the golden hamster.

Recently, we reported that male accessory sex gland (ASG) secretions protect sperm genomic integrity by demonstrating that DNA damage was more extensive in sperm not exposed to the secretions. The present study was conducted to find out if ASGs secrete the main antioxidant enzymes superoxide dismutase (SOD), glutathione peroxidase (GPx or GSH-Px), and catalase (CAT) and if the most abundant one, SOD, can protect those sperm that were not exposed to ASG secretions against NADPH-induced oxidative stress. Four experimental groups of male golden hamsters were used: intact animals with proven fertility, animals with all major ASGs removed (TX), animals that were bilaterally vasectomized, and sham-operated controls. SOD, CAT, and GPx activities were measured in secretions from all 5 ASGs and sperm-free uterine flushing from virgin females and those mated with the experimental males. The alkaline comet assay was used to analyze DNA integrity of the TX group sperm after incubation in a medium containing 50 U/mL of SOD along with 0 to 20 mmol/L NADPH. The main antioxidant enzyme in ASGs was SOD from coagulating glands (P <.05) and GPx together with CAT from ampullary glands (P <.05). Uterine flushing of ejaculates that contained ASG secretions had more SOD and CAT activities than those with epididymal secretions alone (P <.05 and P <.001, respectively), whereas activity of GPx was the same (P >.05). Addition of SOD in vitro dose dependently decreased the incidence of single-strand DNA damage in sperm not exposed to ASG secretions incubated in the presence of 0 to 20 mmol/L NADPH (P <.001). These results indicated that, in terms of abundance, SOD was the main antioxidant enzyme secreted by male ASGs, whereas CAT was the second one. The GPx activity came from both epididymis and ASGs. We conclude that ASG secretions play a significant role in protecting sperm against oxidative stress.

Intermedin attenuates LPS-induced inflammation in the rat testis.

First reported as a vasoactive peptide in the cardiovascular system, intermedin (IMD), also known as adrenomedullin 2 (ADM2), is a hormone with multiple potent roles, including its antioxidant action on the pulmonary, central nervous, cardiovascular and renal systems. Though IMD may play certain roles in trophoblast cell invasion, early embryonic development and cumulus cell-oocyte interaction, the role of IMD in the male reproductive system has yet to be investigated. This paper reports our findings on the gene expression of IMD, its receptor components and its protein localization in the testes. In a rat model, bacterial lippolysaccharide (LPS) induced atypical orchitis, and LPS treatment upregulated the expression of IMD and one of its receptor component proteins, i.e. receptor activity modifying protein 2 (RAMP2). IMD decreased both plasma and testicular levels of reactive oxygen species (ROS) production, attenuated the increase in the gene expression of the proinflammatory cytokines tumor necrosis factor alpha (TNFα), interleukin 6 (IL6) and interleukin 1 beta (IL1ß), rescued spermatogenesis, and prevented the decrease in plasma testosterone levels caused by LPS. The restorative effect of IMD on steroidogenesis was also observed in hydrogen peroxide-treated rat primary Leydig cells culture. Our results indicate IMD plays an important protective role in spermatogenesis and steroidogenesis, suggesting therapeutic potential for IMD in pathological conditions such as orchitis.

Decreases in adrenomedullin expression and ciliary beat frequency in the nasal epithelium in tubal pregnancy.

OBJECTIVE: To study adrenomedullin (ADM) expression and its relation to ciliary beat frequency (CBF) in the nasal mucociliated epithelium in tubal ectopic pregnancy (tEP). DESIGN: Experimental study. SETTING: University teaching hospital. PATIENT(S): Women with tEP and normal intrauterine pregnancy matched for age and gestational age were recruited. Healthy nonpregnant women were also recruited as nonpregnant controls. INTERVENTION(S): Nasal epithelial brushing. MAIN OUTCOME MEASURE(S): Adrenomedullin expression in nasal epithelium (measured by real-time reverse transcription-polymerase chain reaction, plasma ADM concentration (measured by ELISA), and CBF (measured by photometric method). RESULT(S): We have demonstrated a similar decrease in ADM expression and CBF in the nasal mucociliated epithelium, as well as in plasma ADM concentration, in women with tEP compared with normal pregnant women. Adrenomedullin up-regulates nasal CBF via the ADM receptor, as in the oviduct. There is significant correlation between nasal and oviductal CBF. CONCLUSION(S): Nasal epithelium ADM and CBF, as well as plasma ADM, are possible predictors of women at risk of tEP.

Preimplantation antagonism of adrenomedullin action compromises fetoplacental development and reduces litter size.

Concentrations of adrenomedullin (ADM) in circulation, the uterus, and corpora lutea (CL) increase during pregnancy. We previously reported a temporal-spatial pattern of ADM level and gene expression of Adm and its receptor components, from early pregnancy through midpregnancy to late pregnancy in rats. Two earlier reports using an in vivo model of ADM antagonism demonstrated the important roles of ADM in the post-implantation period. Treatment with ADM receptor blocker hADM22-52 starting from gestation Day 8 or Day 14 resulted in fetal-placental growth restriction and reduction in litter size. In this study, the endogenous ADM actions were abolished in the preimplantation period by infusing the antagonist for the ADM receptor (hADM22-52) with the osmotic (Alzet) pump from Days 1-4 of pregnancy. We inferred that ADM, acting through the ADM receptor, had critical roles during preimplantation, as brief inhibition of ADM action by hADM22-52 during this period reduced litter size by restricting placental growth and increasing fetal resorption in midpregnancy.

Adrenomedullin inhibits norepinephrine-induced contraction of rat seminal vesicle.

OBJECTIVE: To investigate the effect of adrenomedullin (ADM) on seminal vesicle smooth muscle contractions in the rat and the specific receptor involved. Whether it was dependent on the nitric oxidant pathway was also investigated. METHODS: The seminal vesicles from Sprague-Dawley rats aged 8-10 weeks were incubated in Kreb's solution. Using an organ bath technique, the contraction of the seminal vesicle in response to norepinephrine (NE) and ADM was recorded, in the presence or absence of an ADM receptor blocker (hADM22-52), a calcitonin-gene-related peptide (CGRP) receptor blocker (hCGRP8-37), and L-NG-nitroarginine methyl ester, an endothelial nitric oxide synthase inhibitor. The basal tone, amplitude, and frequency of contraction were measured after incubation with the drugs. RESULTS: The results showed that the contraction induced by NE was effectively inhibited by ADM. The basal tone, amplitude, and frequency all decreased. The ADM effects on the NE-induced increases in basal tone and amplitude were completely blocked by hCGRP8-37, the CGRP receptor antagonist, but were not abolished by L-NG-nitroarginine methyl ester. CONCLUSION: The findings have demonstrated that in the seminal vesicle the inhibitory effect of ADM on NE-induced contraction was mediated by the CGRP receptor but not by nitric oxide production.