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PubMed1996

Laboratory evaluation of women experiencing reproductive failure.

Reproductive life table analysis indicates that the majority of reproductive failures result from post fertilization failures, whether before or after implantation. It is important to have a set of tests to clarify the diagnosis of the reproductive failure so that appropriate therapy can be instituted. To determine the frequency of abnormal immunologic tests among women experiencing reproductive failure, 108 patients were evaluated for the presence of antiphospholipid antibodies (APA); lupus anticoagulant (LA); thyroid-thyroglobulin and microsomal antibodies (TGT); embryotoxic factor (ETA); and systemic CD56+/CD16- cells. The frequency of abnormal results obtained from testing for APA, LA, TGT, ETA, and CD56+/CD16- cells among 108 patients with diagnoses of recurrent pregnancy loss (RPL)(n = 45), unexplained infertility (n = 45) including IVF failure (n = 10), endometriosis (n = 10), premature ovarian failure (n = 5), and polycystic ovaries (n = 3) were compared with 15 normal controls. Seventy of one hundred eight (65%) women experiencing reproductive failure had at least one positive test, compared to 1 of 15 (7%) controls (P = 0.0001). Presence of phospholipid antibodies was the most frequently abnormal result followed by elevated CD56+/CD 16 cells. The prevalence of a particular abnormal test varied among the diagnoses. The most frequent abnormal test among women with RPL was an increased percentage of CD56+/CD16- cells (40%), followed by APAs (29%), TGT (9%), and ETA (7%). The most frequent abnormal result among women with unexplained infertility was the presence of APAs (42%), followed by CD56+/CD16- cells (16%), ETA (16%), and TGT (9%). APA, CD56+/CD16- cells, ETA, and TGT are useful tools to assist in the diagnosis of reproductive failure.

Abortion, Habitual↗

PubMed2002

Historical control data on reproductive abilities and incidences of spontaneous fetal malformations in Wistar Hannover GALAS rats.

Wistar Hannover rats, which have recently been introduced into Japan, are expected to be used in reproductive and developmental toxicity studies, yet the accumulation of background data is insufficient. This paper describes our historical data on the reproductive ability of this strain of rat. Three lots of sexually matured females (40 each) were received from CLEA JAPAN, Inc. with males of the same strain (30 or 36 each) and mated. A total of 47 dams were killed on gestation day 20 to examine their fetuses. The remaining 71 pregnant females were allowed to deliver spontaneously and observed for common reproductive parameters. The mating and fertility indices of females were both 99.2%. Overall mean numbers of implants and live fetuses at cesarean sectioning were 12.5 and 11.5, respectively. Fetal resorptions and deaths occurred at an incidence of 8.6%. Morphological examinations of fetuses revealed low incidences of spontaneous malformations (each one case of double aortic arch and absent cervical vertebral arch) and a variety of common variations. The followings are overall means of major reproductive parameters obtained from females with live birth: no. of implants, 12.5; no. of pups delivered, 11.8; viability index of pups at birth, 99.8%; and days of age at sexual maturation (vaginal opening and preputial separation), 30.3 and 42.8, respectively. Our present observations confirmed a minimal deviation among 3 lots of animals in terms of reproductive abilities. These results suggest that this strain of rat can be used in reproductive and developmental toxicity studies, although the sensitivity to toxicants remains to be elucidated.

Animals↗

PubMed1986

Reproduction of complex movements: the effects of the presence of vision during encoding or at recall.

This study investigated the role of vision in the encoding and reproduction of movement. Kinaesthetic reproductions of a kinaesthetically presented two-dimensional movement were compared with reproductions where vision was present either during the standard or at reproduction. The main finding was that the presence of vision during the standard resulted in poorer accuracy and greater underestimation of movement size than when it was absent throughout or present during reproduction. The presence of vision during the standard, however, resulted in less distortion of the linear components of movement shape although no such effect was found for the angular components. The initial direction of movement was reproduced more accurately where visual experience of the movement was given, either during the standard or during reproduction.

Adult↗

PubMed2005

Theory and design of sound field reproduction in reverberant rooms.

With the recent emergence of surround sound technology, renewed interest has been shown in the problem of sound field reproduction. However, in practical acoustical environments, the performance of sound reproduction techniques are significantly degraded by reverberation. In this paper, we develop a method of sound field reproduction for reverberant environments. The key to this method is an efficient parametrization of the acoustic transfer function over a region of space. Using this parametrization, a practical method has been provided for determining the transfer function between each loudspeaker and every point in the reproduction region. Through several simulation examples, the reverberant field designs have been shown to yield a reproduction accuracy as good as conventional free-field designs, and better than multipoint least squares designs when loudspeaker numbers are limited. The successful reproduction of sound over a wide frequency range has also been demonstrated. This approach reveals the appropriate choices for fundamental design parameters.

Journal Article↗

PubMed1984

Progesterone-like effects of estradiol on reproductive behavior and hypothalamic progestin receptors in the female rat.

During the rat estrous cycle, estradiol (E2) and progesterone (P) synergize to activate reproductive behavior. However, receptivity and proceptivity can be elicited by E2 alone in ovariectomized (OVX) animals, particularly when E2 doses are high. The purpose of this study was to determine the neuroendocrine mechanism by which E2 elicits P-dependent reproductive behavior. Adult OVX females received estrogen treatment for 72 h, which consisted of 5 mm Silastic capsules containing 100% E2 or 10% E2, or of 3 injections of estradiol benzoate (EB; 20 micrograms daily). At 72 h, animals were sacrificed for nuclear progestin receptor (NPR) measurements, while others were tested for reproductive behavior. The remaining animals received 1-mg injections of E2, P, moxestrol (Mox) or oil, and either were sacrificed 2 h later for NPR measurements or were tested 4 h later for reproductive behavior. A subset of the animals receiving 1 mg E2 received concurrent administration of the protein synthesis inhibitor, anisomycin (ANI; 100 mg/kg). Acute administration of 1 mg of E2 or P significantly elevated proceptivity, receptivity and NPRs in the mediobasal hypothalamus-preoptic area (MBH-POA) and pituitary (PIT) in females primed with 100% E2. An equivalent dose of Mox was without effect. ANI blocked the acute activation of feminine reproductive behavior by 1 mg of E2. In the absence of acute steroid administration, animals primed for 72 h with EB showed higher levels of reproductive behavior than animals primed with 100% E2.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed2003

The study of reproductive outcome and the health of offspring of UK veterans of the Gulf war: methods and description of the study population.

BACKGROUND: The aim of this study is to determine whether Gulf war veterans and their partners are at increased risk of adverse reproductive events and whether their children have increased risk of serious health problems. Methods and response to the study are reported here. METHODS: This was a retrospective cohort study of reproduction among UK Gulf war veterans, with a comparison cohort of Armed Service personnel who were not deployed to the Gulf. Reproductive history and details of children's health was collected by means of a validated postal questionnaire. A separate study of non-responders was conducted. RESULTS: Questionnaires were returned by a total of 25,084 Gulf war veterans (24,379 men) and 19,003 (18,439 men) subjects in the comparison group. After adjusting for undelivered mail the response rate was 53% for Gulf war veterans and 42% for non-Gulf veterans among men, 72% and 60% among women. Data from the non-responder study suggests that failure to respond to the main survey was largely unrelated to reproduction. 11,155 (46%) male Gulf war veterans and 7,769 (42%) male non-Gulf war veterans had conceived, or attempted to conceive, since the Gulf war. They reported 16442 and 11517 pregnancies respectively in that period. For women, 313 (44%) Gulf veterans and 235 (42%) non-Gulf veterans reported 484 and 377 pregnancies respectively conceived since the Gulf war. CONCLUSIONS: This survey enabled collection of information on a range of reproductive outcomes from veterans of the Gulf war and a suitably matched comparison cohort. Although the response rate for men was disappointing, selection bias related to reproduction does not appear to be strong in these data.

Abortion, Spontaneous↗

PubMed2006

Characterization of the aldo-keto reductase 1C gene cluster on pig chromosome 10: possible associations with reproductive traits.

BACKGROUND: The rate of pubertal development and weaning to estrus interval are correlated and affect reproductive efficiency of swine. Quantitative trait loci (QTL) for age of puberty, nipple number and ovulation rate have been identified in Meishan crosses on pig chromosome 10q (SSC10) near the telomere, which is homologous to human chromosome 10p15 and contains an aldo-keto reductase (AKR) gene cluster with at least six family members. AKRs are tissue-specific hydroxysteroid dehydrogenases that interconvert weak steroid hormones to their more potent counterparts and regulate processes involved in development, homeostasis and reproduction. Because of their location in the swine genome and their implication in reproductive physiology, this gene cluster was characterized and evaluated for effects on reproductive traits in swine. RESULTS: Screening the porcine CHORI-242 BAC library with a full-length AKR1C4 cDNA identified 7 positive clones and sample sequencing of 5 BAC clones revealed 5 distinct AKR1C genes (AKR1CL2 and AKR1C1 through 4), which mapped to 126-128 cM on SSC10. Using the IMpRH7000rad and IMNpRH212000rad radiation hybrid panels, these 5 genes mapped between microsatellite markers SWR67 and SW2067. Comparison of sequence data with the porcine BAC fingerprint map show that the cluster of genes resides in a 300 kb region. Twelve SNPs were genotyped in gilts observed for age at first estrus and ovulation rate from the F8 and F10 generations of one-quarter Meishan descendants of the USMARC resource population. Age at puberty, nipple number and ovulation rate data were analyzed for association with genotypes by MTDFREML using an animal model. One SNP, a phenylalanine to isoleucine substitution in AKR1C2, was associated with age of puberty (p = 0.07) and possibly ovulation rate (p = 0.102). Two SNP in AKR1C4 were significantly associated with nipple number (p </= 0.03) and another possibly associated with age at puberty (p = 0.09). CONCLUSION: AKR1C genotypes were associated with nipple number as well as possible effects on age at puberty and ovulation rate. The estimated effects of AKR1C genotypes on these traits suggest that the SNPs are in incomplete linkage disequilibrium with the causal mutations that affect reproductive traits in swine. Further investigations are necessary to identify these mutations and understand how these AKR1C genes affect these important reproductive traits. The nucleotide sequence data reported have been submitted to GenBank and assigned accession numbers [GenBank:DQ474064-DQ474068, GenBank:DQ494488-DQ494490 and GenBank:DQ487182-DQ487184].

Alcohol Oxidoreductases↗

PubMed1993

Estrogen receptors, estradiol, and diethylstilbestrol in early development: the mouse as a model for the study of estrogen receptors and estrogen sensitivity in embryonic development of male and female reproductive tracts.

To date, there is no conclusive evidence that ERs are present in preimplantation embryos. There are reports that estrogen is made by the rabbit blastocyst (61), and estrogens have been used to induce implantation in mice (62), but whether estrogens act through ERs in the embryo or in the maternal uterus is not known. ERs may be present in early embryos, but if so, levels are below the methods of detection used thus far. Perhaps with more sensitive immunodetection methods, it may be possible to detect ERs in embryos if they are present. Using PCR, messenger RNA for ER has been detected as early as the oocyte stage in mouse embryos (Q. Hou and J. Gorski, unpublished results). This was confirmed recently by Wu et al. (83a). Figure 7 shows a model for the pattern of ER expression in the developing mouse fetus based on the various reports discussed in this review. ERs are present in the 10-day mouse fetus, possibly in the developing ambisexual reproductive tract. Analysis of seven individual 10-day-old fetuses taken from the same litter showed similar levels of an immunostained protein the size of the ER in each fetus (57). The pattern of expression of ER between implantation and the development of the reproductive tract may be the same in male and female mice. Estrogen, acting through ERs, may be one factor (of many) that determines which cells are destined to be part of the indifferent reproductive tract. We were not able to isolate fetal mouse reproductive tracts at an indifferent stage (day 10) due to their very small size. One way to study ER in the indifferent reproductive tract would be to examine these tissues in a larger animal, such as the bovine, using similar immunodetection methods. The distribution of ER in the fetal mouse reproductive tract on fetal days 13 (before sexual differentiation) and 15 (initiation of sexual differentiation) is similar in males and females (71, 72). Thus, estrogen does not appear to be responsible for the initiation of sexual differentiation. Early experiments by Jost (41) showed that removal of the gonad from male or female rabbit fetuses resulted in the female phenotype, which lent weight to the hypothesis that ovarian hormones are not critical in the development of the female phenotype, whereas testicular hormones are essential for the development of the male phenotype.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed1996

Stimulation of epidermal growth factor gene expression during the fetal mouse reproductive tract differentiation: role of androgen and its receptor.

We have shown previously that epidermal growth factor (EGF) plays a role in testosterone-dependent fetal Wolffian duct differentiation. To further assess the role for EGF, we determined whether EGF gene expression was modulated in response to male reproductive tract differentiation. The expression of EGF messenger RNA (mRNA) was measured by an RT-PCR assay using primer pairs spanning the coding sequence of 3228 nucleotide (nt) to 3401 nt. Using the RT-PCR reaction, an amplimer of the expected size, 173 bp, was detected in the fetal male reproductive tract. The amplimer hybridized with a radioactive probe representing an internal sequence of the amplified product and was digested by the restriction enzyme HaeIII, which has an unique cleavage site at 3365 nt. The level of EGF mRNA at different stages of sexual differentiation was measured by a newly developed quantitative competitive RNA PCR (QCPCR) assay for EGF mRNA. The assay was sensitive and reproducible within a linear range of amplification with 5 x 10(4) to 140 x 10(4) copies of mRNA. Using the quantitative competitive RNA PCR we found that the level of EGF mRNA was higher in the male reproductive tract than that in the female reproductive tract. Exposure to testosterone (40 mg/kg.day) during days 13-17 of gestation induced the Wolffian duct in the female fetuses and resulted in stimulation of EGF-mRNA expression. Similarly, an antiandrogen receptor, flutamide (100 mg/kg.day) exposure during days 13-17 of gestation inhibited male reproductive tract differentiation and resulted in inhibition of EGF-mRNA expression. Moreover, during the differentiation of the male reproductive tract there was a biphasic increase in the level of EGF-mRNA, first at day 14 of gestation, the period of onset of testicular activity and Wolffian duct morphogenesis, and second at day 18 of gestation, corresponding to onset of differentiation of the urogenital sinus, epididymal duct, and seminal vesicle. Thus, it appears that testosterone-induced male sexual differentiation is accompanied by an increase in EGF gene expression.

Androgens↗

PubMed1996

The role of epidermal growth factor receptor (EGFR) in male reproductive tract differentiation: stimulation of EGFR expression and inhibition of Wolffian duct differentiation with anti-EGFR antibody.

We have shown previously that epidermal growth factor (EGF) plays a role in testosterone-dependent fetal Wolffian duct differentiation. To assess the role of EGF further, we examined EGF receptor (EGFR) expression during Wolffian duct differentiation and determined whether inhibition of EGFR results in inhibition of Wolffian duct differentiation. Using a polyclonal anti-EGFR antibody in the Western blot analysis, we have detected an immunoreactive band at the expected 180-kDa size, the molecular size for the EGFR protein, in the 18-day fetal male reproductive tract. The mouse 3T3 cell line, used as a positive control, also produced an immunospecific band at the same region. The intensity of the immunoreactive 180-kDa band in the 18-day male reproductive tract significantly decreased after pretreatment of the antibody with the 3T3 cell extract. Nonimmune serum produced no band at the 180- kDa region, suggesting EGFR specificity of the 180-kDa band. The level of the 180-kDa EGFR protein was found to be higher in the 18-day male than in the female reproductive tract. Testosterone increased expression of the EGFR level in the 18-day masculinized female reproductive tract, and it induced Wolffian duct morphogenesis. Under in vitro culture conditions, the anti-EGFR antibody prevented Wolffian duct differentiation, induced by the fetal testis, suggesting a direct role of EGFR in male reproductive tract differentiation. No such effect was found when tested with nonimmune serum. Anti-EGFR also blocked the development of the Wolffian duct in the female explant, induced by exogenous EGF. Thus, a role of EGFR mediating the effect of EGF during male reproductive tract differentiation is demonstrated.

Animals↗

PubMed2005

Health care-related economic burden of the polycystic ovary syndrome during the reproductive life span.

CONTEXT: The polycystic ovary syndrome (PCOS) is the most common endocrine abnormality of reproductive-aged women today, affecting approximately 6.6% of unselected reproductive-aged women (approximately 4 million women in the United States) (1990 National Institutes of Health criteria), and potentially represents a significant financial burden to our health care. OBJECTIVE: The objective of the study was to define, using current definitions and prevalence or incidence data, the minimal economic burden that PCOS in reproductive-aged women represents for the United States. DESIGN: The study design was a literature review. SETTING: The study was conducted at a tertiary care center. PATIENTS OR OTHER PARTICIPANTS: There were no patients or other participants. INTERVENTION(S): We performed a systematic review of the published medical literature to identify studies evaluating epidemiology of reproductive-age PCOS and its clinical consequences and costs. We tied general societal cost data for the different health consequences to reproductive-age PCOS costs, using prevalence data. MAIN OUTCOME MEASURE(S): The main measure in the study was total health care-related economic costs. RESULTS: We estimated the mean annual cost of the initial evaluation to be dollar 93 million (2.1% of total costs), that of hormonally treating menstrual dysfunction/abnormal uterine bleeding to be dollar 1.35 billion (31.0% of total), that of providing infertility care to be dollar 533 million (12.2% of total), that of PCOS-associated diabetes to be dollar 1.77 billion (40.5% of total), and that of treating hirsutism to be dollar 622 million (14.2% of total). CONCLUSIONS: The total cost of evaluating and providing care to reproductive-aged PCOS women in the United States is dollar 4.36 billion. Because the cost of the diagnostic evaluation accounted for a relatively minor part of the total costs (approximately 2%), more widespread and liberal screening for the disorder appears be a cost-effective strategy, leading to earlier diagnosis and intervention and possibly the amelioration and prevention of serious sequelae.

Adolescent↗

PubMed1989

Translational status of proenkephalin mRNA in the rat reproductive system.

The mRNA for the opioid peptide precursor proenkephalin is widely distributed throughout the male and female reproductive systems of rodents. In the present studies, the concentrations of proenkephalin-derived peptides in selected reproductive tissues of the rat have been determined. When compared with previously characterized tissues such as brain, the peptide contents in reproductive tissues were unexpectedly low relative to the abundance of proenkephalin mRNA. This suggested that either translation of proenkephalin mRNA is relatively inefficient in reproductive tissues or that the turnover of proenkephalin products occurs at a higher rate, or both. To distinguish between these possible mechanisms, the polysomal distributions of proenkephalin mRNA in different rat reproductive tissues and in rat brain were determined. In adult rat testis, in which the predominant proenkephalin RNA is the 1700-nucleotide form present in spermatogenic cells, the transcript was found to be mainly associated with translationally inactive ribonucleoprotein fractions. In contrast, the 1450-nucleotide form of proenkephalin mRNA appeared to be translated to a similar extent in rat brain, epididymis, ovary, and somatic cells of the immature rat testis. It therefore appears that inefficient translation of proenkephalin mRNA in spermatogenic cells is a major determinant of the low ratio of proenkephalin peptides to RNA in the adult rat testis, while posttranslational mechanisms (most likely peptide turnover) are involved in the rat epididymis, ovary, and presumably other reproductive tissues. These findings also indicate that mRNA and/or translation product concentrations within a given tissue are not always accurate indicators of the level of peptide or protein production.

Animals↗

PubMed2003

Serum levels of 2,2',4,4',5,5'-hexachlorobiphenyl (CB-153) in relation to markers of reproductive function in young males from the general Swedish population.

A time-related deterioration in male reproductive function caused by exposure to endocrine disrupters, including persistent organochlorines (POCs), has been hypothesized. In animal studies, POCs were found to have adverse effects on male reproductive function. However, little is known about the impact of POC exposure on reproductive parameters in men. In a study of 305 young Swedish men 18-21 years old from the general population, we correlated lipid-adjusted serum levels of 2,2',4,4',5,5' -hexachlorobiphenyl (CB-153)--an index substance for POC exposure--to markers of male reproductive function: testis size assessed by ultrasound, sperm concentration, total sperm count, sperm motility assessed manually and with a computer-aided sperm analyzer (CASA), and serum levels of follicle-stimulating hormone, inhibin B, testosterone, sexual hormone-binding globulin (SHBG), luteinizing hormone, and estradiol. We found weak but statistically significant, negative correlations between CB-153 levels and both the testosterone:SHBG ratio (r = -0.25, p < 0.001)--a measure of the biologically active free testosterone fraction--and CASA sperm motility (r = -0.13, p = 0.02). No statistically significant association with other seminal, hormonal, or clinical markers of male reproductive function was found. In previous studies of more highly POC-exposed groups of adult men, the correlation between POC exposure, including CB-153, and free testosterone levels was not statistically significant. The present study gives some tentative support for weak negative effects of CB-153 exposure on sperm motility and free testosterone levels in young men, but further semen studies on more highly exposed groups may give more firm conclusions on the hazard for male reproductive function from dietary POC exposure.

Adolescent↗

PubMed2004

Long-term exposure to environmental concentrations of the pharmaceutical ethynylestradiol causes reproductive failure in fish.

Heightened concern over endocrine-disrupting chemicals is driven by the hypothesis that they could reduce reproductive success and affect wildlife populations, but there is little evidence for this expectation. The pharmaceutical ethynylestradiol (EE2) is a potent endocrine modulator and is present in the aquatic environment at biologically active concentrations. To investigate impacts on reproductive success and mechanisms of disruption, we exposed breeding populations (n = 12) of zebrafish (Danio rerio) over multiple generations to environmentally relevant concentrations of EE2. Life-long exposure to 5 ng/L EE2 in the F1 generation caused a 56% reduction in fecundity and complete population failure with no fertilization. Conversely, the same level of exposure for up to 40 days in mature adults in the parental F0 generation had no impact on reproductive success. Infertility in the F1 generation after life-long exposure to 5 ng/L EE2 was due to disturbed sexual differentiation, with males having no functional testes and either undifferentiated or intersex gonads. These F1 males also showed a reduced vitellogenic response when compared with F0 males, indicating an acclimation to EE2 exposure. Depuration studies found only a partial recovery in reproductive capacity after 5 months. Significantly, even though the F1 males lacked functional testes, they showed male-pattern reproductive behavior, inducing the spawning act and competing with healthy males to disrupt fertilization. Endocrine disruption is therefore likely to affect breeding dynamics and reproductive success in group-spawning fish. Our findings raise major concerns about the population-level impacts for wildlife of long-term exposure to low concentrations of estrogenic endocrine disruptors.

Animals↗

PubMed1988

The use of rabbits in male reproductive toxicology.

The rabbit is the smallest and least expensive laboratory animal in which serial semen samples can be obtained for morphologic, biochemical, and fertility evaluation. The female rabbit has a predictable reproductive cycle and can be artificially inseminated with a known amount of sperm during fertility testing. These advantages make the rabbit an extremely valuable model for studying the effects of chemicals or other stimuli on the male reproductive system. Quantitative evaluation of the testis, semen, and accessory reproductive organs is important in order to detect subtle effects of a chemical on reproductive capacity. Evaluation of testis size, serum hormone concentrations, and the number, morphology, motility, and fertility of sperm in the ejaculate can be performed serially in the live rabbit. Weights of testes and accessory reproductive organs, estimates of daily sperm production, and histomorphometric data on the seminiferous epithelium can be obtained after sacrifice. Multinucleated spermatids, focal tubular hypospermatogenesis, swelling of spermatocytes, and cytoplasmic vacuoles in Sertoli's cells occur commonly in testes of control rabbits. These changes may be confused with toxic lesions. The incidence of multinucleated spermatids may be increased by stress associated with handling or the environment. Histomorphometric evaluation may be required to prove that a test compound has an adverse effect on the male reproductive system.

Animals↗

PubMed1998

Reproductive experience and opioid regulation of luteinizing hormone release in female rats.

The objective of the present study was to determine whether reproductive experience that produces shifts in opioid regulation of prolactin secretion and behavioural functions also alters opioid regulation of LH during the oestrous cycle or lactation. In Expt 1 the effect of naloxone administration (i.v.) on LH was compared between age-matched, nulliparous and primiparous, catheterized female rats on dioestrus II. In Expt 2, the effects of multiple reproductive experiences on opiate control of LH were investigated using cyclic, nulliparous and multiparous (three litters) rats. In both experiments, no differences in naloxone-stimulated LH release were found between groups even though multiple reproductive experiences resulted in the prolongation of oestrous cyclicity. In Expt 3, day 8 lactating primiparous rats were administered 2, 5, 10 or 25 mg naloxone kg-1 i.v. The three lowest naloxone doses, but not the 25 mg kg-1 dose, significantly increased LH concentrations. The possible effects of prior reproductive experience on opioid control of LH during lactation were then investigated. Naloxone at 0.5 mg kg-1, but not at 2 mg kg-1 or 10 mg kg-1, stimulated a significantly greater rise in LH in multiparous (two litters) than in primiparous females. Overall, these data indicate that while modest differences were found in naloxone-induced LH responses between multiparous and primiparous animals during lactation, reproductive experience did not significantly alter opioid regulation of LH during subsequent oestrous cycles at the naloxone doses examined. Hence, the effects of reproductive experience on opioid regulation of LH are less pronounced than those previously found for opioid regulation of prolactin and behaviour.

Analysis of Variance↗

PubMed1999

Ontogeny of LH receptor gene expression in the pig reproductive tract.

In view of the recently documented expression of the LH receptor gene in several nongonadal reproductive tissues, the aim of this study was to analyse further the ontogeny of expression of this gene in the pig reproductive tract in fetal and neonatal life. RT-PCR was used to investigate the expression of the extracellular and transmembrane receptor domains, and to identify the time of onset of transcription of the full-length LH receptor mRNA and its shorter splice variants. Expression of the LH receptor gene was first detected around day 30 of fetal life in both ovary and testis, coinciding with morphological differentiation. The pattern of expression of LH receptor splice variants did not change during postnatal gonadal maturation. Expression of the LH receptor gene in the pig non-gonadal reproductive tract started during fetal life and continued during sexual maturation. A novel pig LH receptor spliced variant, lacking exon 10, was detected for the first time. The transmembrane receptor domain was expressed in fetal tissues, but not in neonatal control tissues. On the basis of the transmembrane domain of the LH receptor mRNA, it is concluded that the ovary and extragonadal tissues of the pig reproductive tract, like the pig testis, synthesize functional LH receptors during fetal life. The presence of LH receptor mRNA in extragonadal reproductive tissues indicates that LH is involved in the control and regulation of reproductive tract maturation.

Animals↗

PubMed2004

Environmental anti-androgens and male reproductive health: focus on phthalates and testicular dysgenesis syndrome.

The amount of research into endocrine disruption has exploded over the past decade and a re-evaluation of the state of research in this area is timely. There are debates about whether human male reproductive health is really declining and whether endocrine disrupting chemicals play any role in the perceived decline. Most data currently conclude that there are wide geographical variations in semen quality and in the incidence of testicular cancer, cryptorchidism and hypospadias. This review aims to give a brief overview of the issues surrounding the perceived decline in human male reproductive health and the importance of the hormonal environment for the development of the testis and reproductive tract. The consequences for the male reproductive tract of abnormal androgen levels or action are discussed with reference to environmental anti-androgenic compounds. The in vivo data on several anti-androgenic compounds that have been administered to pregnant rodents during the period of male reproductive tract development are assessed with attention to the effects on the male offspring. Finally, the data on in utero phthalate administration are discussed in detail to illustrate the similarities between the effects of some phthalate esters and the human male reproductive tract disorders which comprise testicular dysgenesis syndrome (TDS).

Androgen Antagonists↗