Expression of S100A8 and S100A9 in oviduct epithelial cells induced by estrogen and their possible role in oviduct / 中国药理学通报

Aim To study whether the genes S100A8 and S100A9 are related to the functional regulation of oviduct by estrogen, and to explore their possible effects on fallopian tubes. Methods The basic expression and distribution of S100A8 and S100A9 in ampullary oviduct tissues of healthy sheep in diestrum were verified by immunohistochemistry. The expressions of S100A8 and S100A9 (mRNA and protein) in oviduct epithelial cells were detected by q-PCR and immunofluorescence, the cells were treated by E2 at different time points and different concentrations. Results S100A8 and S100A9 were highly expressed in mucosal epithelium and glandular epithelium of sheep uterine tubes during the diestrum period, and in blood vessels as well. The expression of S100A8 and S100A9 in tubal epithelial cells changed dynamically at different time ponits under the action of high concentration of E2 in vitro, and reached the peak 6 hours after E2 treatment. At this time, different concentrations of E2 significantly induced the high expression of S100A8 and S100A9, but the expressions of S100A8 and S100A9 were the highest at the concentrations of 10-7 mol • L-1 and 10-8 mol • L-1 , and there was no significant difference between the two groups. Conclusions S100A8 and S100A9 in oviduct epithelial cells are regulated by estrogen. Under the regulation of high concentration estrogen, the high expression of SI00A8 and S100A9 may be related to the natural defense of reproductive tract during mating, and may be involved in the transport of eggs in fallopian tube.

Myosalpinx Contractions Are Essential for Egg Transport Along the Oviduct and Are Disrupted in Reproductive Tract Diseases.

Oviducts (also called fallopian tubes) are smooth muscle-lined tubular organs that at one end extend in a trumpet bell-like fashion to surround the ovary, and at the other connect to the uterus. Contractions of the oviduct smooth muscle (myosalpinx) and the wafting motion of the ciliated epithelium that lines these tubes facilitate bidirectional transport of gametes so that newly released ovum(s) are transported in one direction (pro-uterus) while spermatozoa are transported in the opposite direction (pro-ovary). These transport processes must be temporally coordinated so that the ovum and spermatozoa meet in the ampulla, the site of fertilization. Once fertilized, the early embryo begins another precisely timed journey towards the uterus for implantation. Myosalpinx contractions facilitate this journey too, while luminal secretions from secretory epithelial cells aid early embryo maturation.The previous paradigm was that oviduct transport processes were primarily controlled by fluid currents generated by the incessant beat of the ciliated epithelium towards the uterus. More recently, video imaging and spatiotemporal mapping have suggested a novel paradigm in which ovum/embryo transport is highly dependent upon phasic and propulsive contractions of the myosalpinx. A specialized population of pacemaker cells, termed oviduct interstitial cells of Cajal (ICC-OVI), generate the electrical activity that drives these contractions. The ionic mechanisms underlying this pacemaker activity are dependent upon the calcium-activated chloride conductance, Ano1.This chapter discusses the basis of oviduct pacemaker activity, its hormonal regulation, and the underlying mechanisms and repercussions when this activity becomes disrupted during inflammatory responses to bacterial infections, such as Chlamydia.

New perspective on conceptus estrogens in maternal recognition and pregnancy establishment in the pig†.

The proposed signal for maternal recognition of pregnancy in pigs is estrogen (E2), produced by the elongating conceptuses between days 11 to 12 of pregnancy with a more sustained increase during conceptus attachment and placental development on days 15 to 30. To understand the role of E2 in porcine conceptus elongation and pregnancy establishment, a loss-of-function study was conducted by editing aromatase (CYP19A1) using CRISPR/Cas9 technology. Wild-type (CYP19A1+/+) and (CYP19A1-/-) fibroblast cells were used to create embryos through somatic cell nuclear transfer, which were transferred into recipient gilts. Elongated and attaching conceptuses were recovered from gilts containing CYP19A1+/+ or CYP19A1-/- embryos on day 14 and 17 of pregnancy. Total E2 in the uterine flushings of gilts with CYP19A1-/- embryos was lower than recipients containing CYP19A1+/+ embryos with no difference in testosterone, PGF2α, or PGE2 on either day 14 or 17. Despite the loss of conceptus E2 production, CYP19A1-/- conceptuses were capable of maintaining the corpora lutea. However, gilts gestating CYP19A1-/- embryos aborted between days 27 and 31 of gestation. Attempts to rescue the pregnancy of CYP19A1-/- gestating gilts with exogenous E2 failed to maintain pregnancy. However, CYP19A1-/- embryos could be rescued when co-transferred with embryos derived by in vitro fertilization. Endometrial transcriptome analysis revealed that ablation of conceptus E2 resulted in disruption of a number biological pathways. Results demonstrate that intrinsic E2 conceptus production is not essential for pre-implantation development, conceptus elongation, and early CL maintenance, but is essential for maintenance of pregnancy beyond 30 days .

A model of Stokesian peristalsis and vesicle transport in a three-dimensional closed cavity.

The complexity of the mechanics involved in the mammalian reproductive process is evident. Neither an ovum nor an embryo is self-propelled, but move through the oviduct or uterus due to the peristaltic action of the tube walls, imposed pressure gradients, and perhaps ciliary motion. Here we use the method of regularized Stokeslets to model the transport of an ovum or an embryo within a peristaltic tube. We represent the ovum or the embryo as a spherical vesicle of finite volume - not a massless point particle. The outer membrane of the neutrally buoyant vesicle is discretized by nodes that are joined by a network of springs. The elastic moduli of these springs are chosen large enough so that a spherical shape is maintained. For simplicity, here we choose an axisymmetric tube where the geometry of the two-dimensional cross-section along the tube axis reflects that of the sagittal cross-section of the uterine cavity. Although the tube motion is axisymmetric, the presence of the vesicle within the tube requires a fully three-dimensional model. As was found in Yaniv et al. (2009, 2012) for a 2D closed channel, we find that the flow dynamics in a 3D peristaltic tube are strongly influenced by the closed end and the manner in which the peristaltic wave damps out towards the closure. In addition, we demonstrate that the trajectory of a vesicle of finite volume can greatly differ from the trajectory of a massless fluid particle initially placed at the vesicle׳s centroid.

Multifetal pregnancy reduction: a Belgian experience.

Multifetal pregnancy reductions were performed during the first trimester of pregnancy in 26 patients. Transabdominal intrathoracic KC1 injections were performed in 23 cases, and transcervical aspirations in 3 cases. There were 4 miscarriages (15%) during the second trimester, 18 pregnancies ended in 33 births, 4 pregnancies are going on uneventfully and are beyond 32 weeks. There was no maternal morbidity related to the procedure; fetal morbidity has been mild.

PIP: In spite of the successful results of fetal reduction, the author's express concern that the practice not become a part of reproduction management, but as a practice to help infertile couples and prevent the unwanted effects of multiple pregnancies. Since 1977 there has been the ability to promote fertility through use of drugs such as clomiphene citrate and personal and in vitro fertilization with the consequence in multiple embryos. The risks to the mother may be pre-eclampsia, post partum hemorrhage, and thrombophlebitis, and/or fetal pre-maturity, immaturity, and perinatal morbidity and mortality. SInce 1986 fetal reduction techniques have been available. This imposes ethical difficulties. The authors report the results of 22 Belgian patients, who carried 87 fetuses between 1985 and 1989, and received multiple pregnancy reduction (MPR). Of these, 4 are still pregnant at 32 weeks, 4 were lost completely and 1 lost in utero, and 33 live births. The live birth rate was 82% with mild morbidity. 78% were low birth weights including 2 under 1000 grams, but with no losses. It appears from the available evidence that the 15% lost is comparable. The procedure, which is described, was changes from transcervical aspiration to intra thoracic KC1 (potassium chloride) injection due to concern for vaginal bacterial growth, and the safe affects on the remaining fetuses. Complication during pregnancy included three patients with pre- eclampsia, but delivered successfully, and 1 with a Shirodkar cerclage at 20 weeks and with ruptured membranes at 37 weeks, but delivered successfully, and 1 preterm labor at 22 weeks who delivered successfully after 28 weeks with 1 dying in utero. She has been infused with beta- mimetics and maintained on indomethacin in the Trendelenburg position.

The etiology of ectopic pregnancy.

The cause of ectopic pregnancy is associated with two major categories: the integrity of the oviduct and the quality of the fertilized ovum. Several conditions that alter the tubal transport system include inflammatory insults, intrauterine devices, surgical manipulation, tubal ligations, salpingitis isthmica nodusa, DES exposure, and induced abortions. Risk factors that may theoretically alter ovum quality or the hormonal environment include ovulation induction, fertilization in vitro, delayed ovulation, and transperitoneal ovum migration. As we continue to investigate the fallopian tube and the fertilized ovum as unique entities, our knowledge will increase about the cause of ectopic gestations.

PIP: The causes of ectopic pregnancy, divided into those arising from abnormal ovum transport and those due to abnormalities of the egg itself, are presented. The fallopian tube is not a passive conduit, but the active site of sperm capacitation, egg capture and fertilization. Conditions resulting in damage to tubal lining such as salpingitis, even if it is subclinical as often occurs with Chlamydia, increase risk of tubal pregnancy. Other causes of damage to tubes include vaginal douching, especially with commercial products, laparoscopic tubal ligation if it creates fistulas, even microsurgical reconstruction and conservative surgery for prior ectopic pregnancy. For unknown reasons, IUD use, the thickening of the tube seen in salpingitis isthmic nodosa, and exposure to diethylstilbestrol are also risk factors. Unresolved is the controversy over whether previous induced abortions predispose one ectopic pregnancy; possibly 2 or more abortions, or illegal abortions may adversely affect the statistics. Factors detrimental to ovum quality that lead to ectopic pregnancy include induced ovulation, in vitro fertilization, delayed ovulation and migration of the ovum to the contralateral tube.

EFFECT OF VERAPAMIL AND NIFEDIPINE ON OVIDUCT MOTILITY AND OVUM TRANSPORT IN RAT / 中国药理学通报

Calcium blockers verapamil ( VER ) and nifedipine ( NIF ) appa-rentely inhibited the spontaneous activity of isolated rat oviduct. The 5 min contractile curve aera determined by integrator,after eithet VER or NIF effected, was smaller than that before,with dose dependence.In rats pregnanant for 3d VER and NIF accelerated ovum transport through oviduct. The number of ovum recovered from uterus in test group was more than that in control group. Paired experiments showed VER and NIF having no anti-implantation action.

Spontaneous abortion incidence in the treatment of infertility.

Analysis of published series indicates that, irrespective of the method of data collection, close agreement exists on empirically derived incidences of spontaneous abortion in North American populations, provided that age, previous abortion history, and gravidity are controlled. The normal incidence of clinically apparent abortion among first pregnancies in women under age 30 years is in the range 8.3% to 11.0%. A comprehensive analysis of published series on pregnancies after infertility treatment indicates that only three therapeutic methods are attended by an abortion incidence that approaches this asymptote: ovulation induction with bromocriptine in hyperprolactinemic anovulation (11.8%; n = 1,233 pregnancies); artificial insemination with donor semen for azoospermia (11.4%; n = 326 first pregnancies); and operation for endometriosis (9.3%; n = 768 pregnancies). Abortion incidences accompanying other modes of therapy are higher. Because increased abortion incidence is not generally recognized as a specific reproductive difficulty in infertile couples, as are the other two: i.e., refractory infertility despite technically adequate therapy and ectopic pregnancy, plausible physiologic mechanisms for abortions in specific categories of disease or treatment type are described and discussed in detail. Moreover, abortion incidence is proposed to be a sensitive and objective parameter with which to assess distortions in human reproductive physiology, especially when competing methods of infertility treatment have overall pregnancy outcomes that are thought to be similar.

From the NIH: New procedure offers hope for infertile women.

PIP: At the National Institute of Child Health and Human Development (NICHD), a new procedure for overcoming infertility caused by blocked fallopian tubes is being developed. The new procedure -- low-tubal ovum transfer -- circumvents tubal blockages, while permitting in vivo fertilization to occur. In the 1st trial of low-tubal ovum transfer, 16% of the monkeys who underwent the procedure became pregnant. By comparison, human couples of normal fertility have a 15% to 20% chance of pregnancy in a single menstrual cycle. The investigators are hopeful that the procedure will be effective in women with at least 1 fallopian tube that is patent near the uterus. It may be particularly appropriate for women who have undergone voluntary sterilization and who later decide that they want children. If microsurgery fails to repair the tubes, low-tubal ovum transfer may be an alternative. Further studies in monkeys are required as well as eventual trials in women in order to assess both the safety and effectiveness of this procedure.^ieng

THE EFFECT OF DL-TETRAHYDROPALMATINE AND SINOMEMINE ON THE MOTILITY OF OVIDUCT SMOOTH MUSCLE IN RABBITS / 西安交通大学学报(医学版)

The effects of DL-tetrahydropalmatine andsinomemine on the activity of oviduct smooth mus-cle and ovum transport in rabbits are reported inthis paper. The results indicate that the two a-gents apparently inhibit the contractile activity ofoviduct isthmic smooth muscle of rabbit in vitroand decrease the frequency, amplitude, tensionand curve areas of the contraction. The contractileffect induced by noradrenaline is also inhibited re-markbly by them. In addition, DL-THP and Sino.can delay ovum transport in rabbit oviduct after ivHCG 48 h. It is suggested that the inhibition ofactivity of oviduct smooth muscle may be one ofthe important causes of delaying egg transportcaused by the two agents.

Anatomy and physiology of the fallopian tube.

PIP: The anatomy and physiology of the human fallopian tube are described and discussed; then, these facts are correlated with clinical considerations as they relate to tubal factor infertility. Anatomically the human oviduct is a tubular, seromuscular organ attached distally to the ovary and proximally to the lateral aspect of the uterine fundus. Its length averages 11-12 cm. The oviduct can be divided into 4 main segments: 1) the infundibulum, whose terminal end contains the tubal ostium; 2) the ampullary region; 3) the isthmic portion; and 4) the intramural or interstitial portion, which is contained in the wall of the uterus. 4 electron micrographs illustrate these areas. Also discussed in this reveiw are the vascular analtomy, the lymphatics, and neuroanatomy of the fallopian tubes. Physiologic functions discussed in this article include the role of the fallopian tube in sperm transport, its part in sperm maintenance and capacitation, and the tube's function in ovum transport, fertilization, and embryo transport. Clinically, the role of the myosalpinx is undetermined, although it may affect tubal motility and ovum transport. The dense adrenergic innervation of the oviductal isthmus, along with the myosalpinx, suggests that innervation may be required for sphincter-like activity, although again no evidence exists for innervation being required in normal reproduction. The mucosa provides nutrients which may or may not be essential to normal reproduction, and its cilia seems uncritical in gamete transport and embryogenesis. Evidence shows that the uterotubal junction and the ampullary-isthmic junction are not necessary for conception (based on success rates of implantation procedures). Reversal of fimbriectomy is the most difficult and up to 1-cm of ampulla may be removed and resected and still maintain fertility.^ieng

Cyclic changes in the human fallopian tube isthmus and their functional importance.

Morphologic studies in rabbits have indicated that a column of tenacious mucus occupies the isthmic lumen in estrus. This secretion disappears after ovulation, and cilia are prominent at the time of ovum transport through the isthmus. This study was designed to seek evidence of similar mucus in the human fallopian tube isthmus. Isthmic segments were taken from 18 normally ovulating women throughout the menstrual cycle. Specimens were also obtained from 10 other women further to elucidate endocrine dependence of observed morphologic variations. Appearances consistent with luminal isthmic mucus were obtained in two women in the late follicular phase and in one woman immediately after ovulation. Observable mucus was absent and cilia were prominent in women in the early follicular phase, in the luteal phase, postmenopausally, in late pregnancy, and in the puerperium. The results described are consistent with the hypothesis that differential sperm and ovum transport in the human fallopian tube isthmus is at least partially determined by the presence or absence of estrogen-dependent luminal mucus.

PIP: Changes in the isthmic region of the fallopian tubes of rabbits have been studied over time as they affect ovum and sperm transport in the hopes of relating the findings to human cyclic changes in fallopian tube isthmus. In rabbits, morphological studies indicated that a column of mucus is found in the isthmic lumen during estrus. After ovulation, this mucus column disappears, leaving the cilia prominent, presumably to provide motoring for ovum transport through the isthmic area. In this study, fallopian tube specimens from humans were studied to confirm or deny the applicability of these findings in rabbits in terms of human reproductive cycle changes. To this end, isthmic seqments from 18 mormally ovulating women were sampled throughout the menstrual cycle. In addition, 10 other women gave specimens which were used to assess the endocrine dependence of any observed morphological variation. 2 women in late follicular stage and 1 woman just after ovulation showed appearances consistent with luminal isthmic mucus. All women in the early follicular phase had an absence of observable mucus and a prominence of cilia; this was also true of women in luteal phase, postmenopausal women, women in late pregnancy, and pueriperal women. Hence, these findings seem consistent with the hypothesis presented that differential sperm and ovum transport in the human fallopian isthmus is somewhat determined by the presence or absence or estrogen dependent luminal mucus, i.e., the presence of isthmic mucus gives a medium for sperm transport at ovulation, that this medium protects the sperm from ciliary activity, that the persistence of the mucus for 2-3 days postovulation may act to lock the ovum in the ampulla, and the the disappearance of the mucus allows ovum transport.

The diagnostic value of hysterosalpingography in infertility cases: part 2, the radiological appearance of tubal pick-up mechanism "hand pointing sign.".

PIP: Hysterosalpingography was used to determine the appearance of the fallopian tubes at the time of ovulation. 47 of 50 normal fertile patients showed a characteristic radiological sign, designated the tubal hand pointing sign, at the time of expected ovulation. 6 figures depict this tubal alteration. The tubal hand pointing sign is seen as the normal tube spreads laterally from the uterine corne. The proximal part of the tube is nearly straight, followed by a convoluted intermediate part. The infundibulum and fimbria ovarica are seen pointing to the ovary and ovarian bed. The tubal pick=up mechanism was suggested as the cause of the radiological appearance described. In 2 cases depicted, the distal part of the tube is creeping, snake-like, over the ovarian surface and bed. Hence, it is suggested that absence or distortion of this tubal hand pointing sign may be helpful in the diagnosis of infertility.^ieng

Studies on the duration of egg transport by the human oviduct. II. Ovum location at various intervals following luteinizing hormone peak.

The location of ova in the genital tract between 24 and 144 hours following the LH peak was determined in 23 normal women. Nineteen eggs were found in the Fallopian tubes between 24 and 96 hours and five eggs were recovered from the endometrial cavity between 96 and 144 hours following the LH peak. According to the present data and considering that ovulation occurs in the human subject nearly 17 hours after the LH peak, it is concluded that the transport of unfertilized ova in women is characterized by a period of retention in the ampulla, which lasts approximately 72 hours, followed by rapid transit through the isthmus and appearance of the ovum in the endometrial cavity around 80 hours after ovulation.

PIP: This study determined the location of ovum in the genital tracts of women at various intervals after the luteinizing hormone (LH) peak, in order to answer the following questions concerning ovum transport: 1) how soon and for how long after the LH peak can eggs be recovered from the fallopian tube, and 2) what is the relative time spent by eggs in each portion of the fallopian tube. Also addressed was the question of how soon, and for how long after the LH peak, can eggs be recovered from the uterus? 23 normal women were studied and their ova were located in their tubes after surgical intervention, which occurred from 24-144 hours after LH peak, based on results of blood assays for this hormone. In all 19 eggs were found in tubes between 24 and 96 hours and 5 eggs were recovered from the endometrial cavity between 96 and 144 hours after LH peak. Since it has been determined that ovulation occurs about 17 hours after LH peak, these data show that transport of unfertilized ova in women is characterized by a period of retention in the ampulla which last about 72 hours; this retention period is followed by very rapid ovum transit through the isthmus; the ovum appears in the endometrial cavity about 80 hours after ovulation.

From Fallopius to fantasy.

PIP: Knowledge of the female reproductive system in classical times is reviewed briefly. Current knowledge of tubal physiology is explained in greater detail. This knowledge, which is relevant to the study of fertility and sterility, includes sections dealing with: 1) sperm transport; 2) sperm capacitation; 3) fertilization; and 4) ovum and embryo transport. Since human data for some of these areas is lacking, data obtained in the study of other species is used as a supplement. Although it is now believed that microsurgical plastic repair of the fallopian tubes is preferable to macrosurgery, the author maintains that this has not been proven. Proof would involve studies in which the skill of the surgeon, the degree of damage requiring repair, and the method of assessing results were all held constant. The pregnancy rates following microsurgery as compared to those obtained with macrosurgery do not seem to justify the cost, prolonged operating time, and increased risk of ectopic pregnancy associated with microsurgical procedures.^ieng

Comparative aspects of tubal anatomy and physiology as they relate to reconstructive procedures.

PIP: This article reviews the physiology of oviducts in many species, noting differences among various species of experimental animals, and complex mechanisms involved in gamete transport. Both of these topics, physiology and gamete transport, are related to their possible effects on reconstructive procedures of fallopian tubes. An understanding of the mammalian oviduct is essential before operative techniques for reanastomosis of tubes can be refined. The following topics are covered in this article: 1) the oviducts and supporting mesenteries; 2) the tunica serosa; 3) the muscularis; 4) blood and lymphatic vessels; 5) nerve supply; 6) fimbriae; 7) ciliogenesis in the oviductal epithelium, which is an estrogen-producing phenomenon; 8) oviductal ciliated epithelium and the direction of ciliary beat; 9) the ampulla of the oviduct and egg transport; 10) isthmoampullar junction and egg retention; 11) egg transport through the isthmus; and 12) sperm transport through the isthmus.^ieng

On the function of cilia in the female reproductive tract.

A recently discovered syndrome is characterized by congenital immotility of the cilia. It consists of chronic infections in the respiratory system, male infertility, and, in about one-half of the cases, situs inversus. The syndrome thus includes Kartagener's syndrome. The syndrome provides a unique opportunity to gain insight into the role of the cilia in the human body. Five women evidently suffering from this syndrome were examined. They had no gynecologic disorders. Three of the five women had tried to become pregnant and two have suceeded. A review of the literature indicates that men with Kartagener's syndrome are usually infertile, whereas the women are not. This fact and the data presented herein constitute strong evidence that ciliary motility is not essential for female fertility. More conclusive proof could be obtained if any of the affected women would consent to ultrastructural investigation of the oviductal cilia.

PIP: A recently discovered syndrome is characterized by congenital immotility of the cilia. It consists of chronic infections in the respiratory system, male infertility, and in about 1/2 of the cases, situs inversus. The syndrome thus includes Kartagener's syndrome. The syndrome provides a unique opportunity to gain insight into the role of the cilia in the human body. 5 women evidently suffering from this syndrome were examined. They had no gynecologic disorders. 3 of the 5 women have tried to become pregnant and 2 have succeeded. A review of the literature indicates that men with Kartagener's syndrome are usually infertile, whereas the women are not. This fact and the data presented therein constitute strong evidence that ciliary motility is not essential for female fertility. More conclusive proof could be obtained if any of the affected women would consent to ultrasturctural investigation of the oviductal cilia.

Pharmacologic modification of the time course of ovum transport in guinea pigs.

Various agents were examined for their effects on ovum transport in the guinea pig. Estrogen significantly accelerated ovum transport in this species. The experiments further demonstrated that estrogen did not act by inducing prostaglandin synthesis, nor by altering plasma progesterone levels. The estrogen-induced acceleration was significantly antagonized by tamoxifen, an antiestrogen that acts by interfering with estrogen receptor synthesis. Cycloheximide also antagonized the effects of estrogen on ovum transport. These data suggest that the modification of ovum transport by estrogen is due to the entrance of estrogen into the nuclei of target cells, and subsequent protein synthesis. Although we assume that this action occurs at the level of the oviduct, our experiments do not prove this assumption.

PIP: The effects of various agents on the transport of ovum was tested in 39 guinea pigs. The administration of estrogens significantly accelerated this process. Estrogens did not act through the induction of prostaglandin synthesis or by altering plasma progesterone levels. Estrogen-induced ovum acceleration was significantly antagonized by tamoxifen, an antiestrogen that acts by interfering with estrogen receptor synthesis. Cycloheximide also antagonized the effects of estrogen on ovum transport. A modification of ovum transport by estrogens is thought to be due to the entrance of estrogen into the nuclei of the target cells, and through subsequent protein synthesis. It is assumed that this process takes place at the oviduct level, although the experiment did not prove this.

Effect of ovariectomy on egg transport in the rabbit.

PIP: The influence of preovulatory and postovulatory ovarian steroid secretion on ovum transport in rabbits was investigated. Experimental conditions were 1) induction of ovulation with human chorionic gonadotropin (HCG) and transfer of eggs to the oviducts, 2) bilateral ovariectomy and transfer of eggs to the oviducts, and 3) HCG-induced ovulation and bilateral ovariectomy shortly after ovulation. Only 7-26% of the eggs transferred to the oviducts of estrous rabbits could be recovered from the oviducts 48 hours after transfer, compared with 72-86% in controls. No eggs could be found in the oviducts of estrous animals at 72 hours after transfer or ovulation, and only 4-13% of the eggs were located in the oviducts of animals induced to ovulate with HCG. However, about 40% of the eggs were recovered from the oviducts of animals studied under experimental conditions 2 and 3 at 72 hours. Egg transport was delayed in animals ovariectomized shortly after ovulation. The results suggest that preovulatory steroid surges and/or steroid withdrawal impede egg transport, and the postovulatory secretory changes are required to negate this effect.^ieng

Function and malfunction of the Fallopian tubes in relation to gametes, embryos and hormones.

PIP: After a brief historical review of studies on the Fallopian tubes, their functional anatomy is considered with regard to cilia; secretory cells, the mucosa, musculature, innervation, and vasculature. Muscula activity is treated in relation to the transport of gametes and embryos, and secretory activity in relation to the maturation of gametes and development of embryos. The isthmus may function critically in regulating sperm numbers available for fertilization while simultaneously acting as a temporary sperm reservoir, and entry of eggs into the ampulla may stimulate release and capacitation of spermatozoa from the lower regions of the tube. Because of the rapidity of egg transport to the ampullary-isthmic junction, the latter is the site of fertilization in most mammals though apparently this is untrue in women. Subsequent passage of the embryo along the isthmus is under the influence of gonadal steroids, and appears to be regulated locally by an interplay of alpha- and beta-adrenergic receptor activity in the myosalpinx and by tissue prostaglandins, as well as by the extent of edema in the mucosa. The possibility that embryonic secretion of hormones contributes to this control should be recognized as should the role of steroid-induced anomalies of egg transport in the etiology of tubal pregnancies. Tubal fluid is no ed to be composed of serum transudate and specific secretion containing some unique protein(s), and is regulated by the prevailing balance of ovarian hormones, but a trophic influence of the embryo is again considered. Finally, reference is made to clinical problems in the light of evidence obtained from experimental animals, and it is reasoned that attempts to regulate human fertility by modified tubal function could prove to be unsatisfactory.^ieng