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PubMedDate not supplied

Overview of male reproductive pathology.

An understanding of form and function is important for examination of the male reproductive tract. A basic understanding of spermatogenesis and hormonal function in the reproductive tract is essential for the pathologists in this evaluation. Gross and histologic reproductive changes need to be distinguished from normal variation and correlated with the reproductive status of the animal. This is especially important when correlating histologic changes with organ weight and other reproductive parameters, such as seminal analysis data. Sexual maturity of animals and tissue handing can impact interpretation. Sexual immaturity of preclinical safety animals can present challenges for accurate identification of compound-related changes. Likewise, proper handling of unfixed reproductive tissues and appropriate selection of a fixation protocol are important in avoiding artifacts that may interfere with the microscopic evaluation. The histopathology technician needs to recognize testicular landmarks that allow for correct orientation at trimming so the pathologist can assess not only the morphology of seminiferous tubules but also the outflow tract. For the most effective evaluation of the male reproductive tract, the testes and epididymides should be examined concurrently. Although the term "staging" is often used inappropriately, the pathologist should review testicular tissues in a "stage-aware" manner. This article reviews gross and histologic changes of the male reproductive tract as well as tissue orientation and fixation to assist in accurate interpretation of potential treatment-related changes in male reproduction.

Animals↗

PubMed2003

Frequency and perceived credibility of reported sources of reproductive health information among primary school adolescents in Arusha, Tanzania.

AIMS: To describe adolescents' sources of reproductive health information and perceived credibility of these sources. METHODS: A questionnaire survey was conducted among 1247 seventh grade pupils in Arusha district; enquiring their sources of reproductive health information and perceived credibility of these sources. Mean scores were computed for each type of information in relation to frequency of source and credibility, and scales for reproductive health information sources and credibility constructed. Analysis of covariance was used to compare mean scores by demographic and sexual behaviour variables. RESULTS: Mass media ranked first as sources of reproductive health information, followed by teachers and health workers. Health workers ranked first in credibility followed by parents, while credibility rating for media was low. Religious leaders and respondents' friends played a rather minor role as sources of reproductive health information, and their credibility ratings were also low. CONCLUSION: Mass media were the most frequent sources of reproductive health information for primary school adolescents, but parents and health workers were regarded as more credible sources. Programmes seeking to promote reproductive health of young people should take into account the diverse arenas through which young people currently obtain reproductive health information, and strive to tap into and strengthen the full range of these arenas. Increased involvement of parents and health workers in providing reproductive health information to young people seem indispensable.

Adolescent↗

PubMed2001

A genome-wide survey of reproductive barriers in an intraspecific hybrid.

Genetic study of the reproductive barriers between related species plays an essential role in understanding the process of speciation. We developed a new method for mapping all possible factors causing deviations from expected Mendelian segregation ratios in F(2) progeny, which substantially contribute to reproductive isolation. A multiresponse nonlinear regression analysis of the allele frequencies of the markers covering an entire genome in the F(2) population was performed to estimate the map position and intensity of the reproductive barriers on each chromosome. In F(2) plants from a cross between a Japonica variety of rice, Nipponbare, and an Indica variety, Kasalath, the deviations of allele frequencies were well explained by 33 reproductive barriers. Of these, 15 reproductive barriers affected the allele transmission rate through the gametophyte and in 9 of these 15 cases, an Indica allele was transmitted at a higher frequency than a Japonica allele. The other 18 reproductive barriers altered the viability of the zygote via its genotype. Two zygotic reproductive barriers showed overdominance and 5 showed underdominance. The most pronounced reproductive barrier, mapped at 62.3 +/- 0.4 cM on chromosome 3, transmitted the Indica allele by 94% through the male gametophyte. The accuracy of the barrier position in the regression analysis was confirmed by progeny analysis. The regression analysis proved to be a powerful tool for detecting and characterizing every reproductive barrier, irrespective of whether it acted on the male or female gametophyte or the zygote.

Chromosome Mapping↗

PubMed2003

Paternal investment directly affects female reproductive effort in an insect.

Female reproductive effort can be influenced by the quality of her mate. In some species, females increase their reproductive effort by differentially allocating resources after mating with high-quality males. Examination of female reproductive effort in relation to male quality has implications for estimating the evolvability of traits and for sexual-selection models. Accurate quantification of reproductive investment is not possible in many species. Butterflies are an exception, as most nectar-feeding species emerge with almost intact reproductive resources, and in some species males provide nutrients at mating that enhance female fecundity. By manipulating male donations and using radioactive isotopes, we quantified the effect of variation in nutrient provisioning on female reproductive effort in two butterfly species. In the greenveined white butterfly, Pieris napi, females increased their reproductive effort after receiving large male donations. By contrast, in the speckled wood, Pararge aegeria, where males do not provide nutrients, female reproductive effort was independent of male ejaculate. Increased reproductive effort in Pieris napi resulted from the production of more eggs, rather than from investing more resources per egg. In this species donating ability is heritable; hence females laying more eggs after mating with high-donating males benefit both through higher fecundity and through the production of high-donating sons.

Animals↗

PubMed1990

Developmental and age-related changes in proteins in the female reproductive tract of Heligmosomoides polygyrus (Nematoda).

Proteins in the female reproductive tract of Heligmosomoides polygyrus at days 8, 16, 35, 90, and 140 postinfection (PI) were examined using polyacrylamide gel electrophoresis. Sixteen-day-old and 140-day-old worms also were examined histochemically. Egg production of these worms was assessed for each age group. In analyzing proteins using electrophoresis, the reproductive tracts were separated into 3 sections: the tip, or anteriormost part of tract, containing oogonia; the middle region, containing developing oocytes; and the posterior region, containing the uterus with fertilized eggs. Three major reproductive tract proteins were identified as having molecular weights of greater than 140 kDa, 115 kDa, and 82 kDa. These were found in all parts of the reproductive tract from worms of all ages except those at 8 days PI (which are too young to produce eggs) and are believed to be yolk proteins. Four low molecular weight proteins (L1-4) are believed to be nucleoproteins. L4 was absent from the posterior section of the reproductive tracts and L3 was limited to the posterior sections and may be associated with sperm stored in the uterus. Of 5 high molecular weight proteins the second heaviest, designated H2, appeared to be relatively more concentrated in the posterior sections of the reproductive tract. An 85-kDa protein was limited to the tip and middle sections of reproductive tracts. Histochemical tests on sectioned H. polygyrus showed strong positive reactions for protein in cytoplasmic granules in developing oocytes and in eggs of younger worms (16 days) but a reduced reaction in older worms (140 days). Strains for collagen showed a slight positive reaction in and between developing oocytes and a strong reaction in the egg shells. Stains for nucleoproteins particularly reacted with sperm stored in the uterus, and slightly reacted with fertilized eggs and the nucleoli of the intestinal and ovarian epithelium. Egg production by H. polygyrus increased to 123 eggs/female/day by 16 days PI but declined from 121 eggs/female/day at 35 days PI to 64 eggs/female/day in worms 140 days old. Electrophoresis indicated no loss in the different types of proteins in the reproductive tract of older worms, but histochemistry and protein content assays suggest that older worms that produce fewer eggs contain a relatively smaller amount of protein in the female reproductive tract.

Aging↗

PubMed1989

Predicting learning and other developmental disabilities: assessment of reproductive and caretaking variables.

As the studies summarized above reflect, there has been considerable progress made toward identifying and quantifying some of the many variables that are known to place infants and children at risk for learning and other related disabilities. Of specific relevance to this chapter are the improvements that have been made in the conceptualization and measurement of reproductive and environmental/caretaking variables. Both of these classes of variables are well known to influence learning disabilities. However, additional research is now needed to firmly establish the specific nature of the influence of these variables. First, it appears that the influence of reproductive and environmental/caretaking variables is different at different age points. However, because not all longitudinal studies include measures of both reproductive and environmental/caretaking variables, it is difficult to adequately evaluate their influence on outcome measures at different ages. With more consistent use of these measures across studies and age groups it will be possible to make the needed comparisons. Second, there needs to be a closer examination across studies that have used similar samples and designs but that report conflicting findings concerning the influence of reproductive and environmental/caretaking variables. The critical differences between these studies need to be identified. For example, it appears that some studies reporting findings of no effects of reproductive measures on developmental outcome are using perinatal risk scales that are different from those used by studies that report reproductive effects. Clearly, it is critical to use perinatal risk scales that are appropriate for the characteristics of the study sample, the study design, and statistical analyses. Beyond these criteria, the selected scales need to have established validity with respect to the measurement questions under study. Overall, consideration needs to be given to the selection of valid and reliable measures of both reproductive and environmental/caretaking variables. Finally, reproductive and environmental/caretaking variables need to be included more consistently in studies as predictors of learning developmental disabilities and not just for the purpose of subject classification and description. By using these variables as predictors in statistical analyses, it will be possible to determine if these variables directly contribute to developmental outcomes and the strength (or importance) of the contributions of these variables compared to other variables. Tracking the role and strength of the contribution made by these variables across age periods will permit the assessment of possible developmental changes in susceptibility to influence by reproductive and environmental/caretaking variables.

Adolescent↗

PubMed1989

Association of sperm measures with reproductive outcome: National Toxicology Program studies in mice.

In reproductive assessment by continuous breeding (RACB) studies, a crossover mating trial was conducted if an adverse effect on fertility was detectable over an 18-week cohabitation period during which Swiss (CD-1) mice were continuously treated. Results of 25 RACB crossover mating studies conducted to determine the affected sex were compared with results of sperm morphology and vaginal cytology examinations (SMVCE) performed at the conclusion of each mating trial. SMVCE endpoints included epididymal sperm concentration, motility, and morphology, vaginal cytology, and male reproductive organ weights. In most studies, multiple SMVCE endpoints were adversely affected. With this group of chemicals, epididymis weight was sensitive and specific to male reproductive toxicants and nontoxicants, respectively. Sperm motility and testis weight were also highly sensitive to male reproductive toxicants. The above endpoints demonstrated the greatest statistical significance relative to other SMVCE parameters, and were highly associated with fertility measurements from breeding experiments. These characteristics suggest that some SMVCE endpoints are more useful for screening chemicals for potential male reproductive toxicity than others. Caution must be exercised, however, because the compounds used in these studies are not representative of all classes of chemicals, and chemicals not tested here may produce adverse reproductive effects by different mechanisms of action. The dose-response effects of two glycol ethers evaluated in RACB, ethylene glycol monomethyl ether and ethylene glycol monoethyl ether, on reproductive outcome and SMVCE endpoints were examined in detail. Both caused adverse effects on testis weight and sperm head morphology, and these changes were associated with adverse effects on reproductive outcome. Until we have more experience with SMVCE and other screens, multiple endpoints should continue to be used for screening for reproductive toxicants.

Animals↗

PubMed2000

Use of reproductive health services among young men, 1995.

PURPOSE: To analyze the extent to which teenage males receive preventive reproductive health services and identify demographic and health factors associated with their receipt. METHODS: Bivariate and multivariate analyses of nationally representative data from the 1995 National Survey of Adolescent Males were conducted using logistic regression to determine which factors predicted whether teenagers had a physical examination and whether they discussed reproductive health topics with a medical professional, had a human immunodeficiency virus (HIV) test, or had a sexually transmitted disease (STD) test. RESULTS: Although 71% of males aged 15-19 years received a physical examination in the past year, only 39% of them received any of the three reproductive health services. Less than one-third of all young men discussed reproductive health with their doctor or nurse. Among sexually experienced males, one-sixth had an STD test and one-quarter an HIV test. In multivariate analysis, males who had a physical examination were more likely to have an STD or HIV test, but were no more likely to discuss reproductive health topics. Minority and low-income youth were more likely to receive these reproductive health services, as were young men with multiple sex partners and those with health problems. CONCLUSIONS: In general, the proportion of teenage men receiving reproductive health services is low, although levels are higher among minority youth and certain groups at risk. To reduce rates of teen pregnancy and STDs, physicians and nurses need to incorporate reproductive health care into routine health services for teenage males, as well as females.

Acquired Immunodeficiency Syndrome↗

PubMed2005

Assisted reproductive practice: religious perspectives.

It is important to those who practise reproductive techniques to learn about different religious perspectives related to reproductive health problems. Religious groups are active in influencing the public regarding bioethical positions, and this is particularly evident with issues concerning procreation, abortion and infertility therapy. The Jewish attitude towards procreation is derived from the first commandment of God to Adam to 'Be fruitful and multiply'. Judaism allows the practice of all techniques of assisted reproduction when the oocyte and spermatozoon originate from the wife and husband respectively. The attitude toward reproductive practice varies among Christian groups. While assisted reproduction is not accepted by the Vatican, it may be practised by Protestant, Anglican and other denominations. According to traditional Christian views, beginning at conception, the embryo has moral status as a human being, and thus most assisted reproductive technologies are forbidden. According to Islam, the procedures of IVF and embryo transfer are acceptable, although they can be performed only for husband and wife. Developments in science and technology and corresponding clinical applications raise new religious questions, often without clear answers. The role of theology in bioethics is integral to clarify perceived attitudes toward these developments for different religious communities. This paper presents the attitude of monotheistic religions to therapeutic procedures, such as IVF-embryo transfer, spermatozoa, oocytes, embryo donation, cryopreservation of genetic material, surrogacy, posthumous reproduction, gender preselection, reproductive and therapeutic cloning.

Attitude↗

PubMedDate not supplied

Is the reduction of birth intervals an efficient reproductive strategy in traditional Morocco?

Birth interval lengths are analysed from reproductive life histories of 517 Berber peasant women of the region of Marrakesh (Southern Morocco), whose fertility developed in a full traditional context. The high mortality rates associated with short birth intervals indicate that a rapid succession of births is detrimental to the progeny. The reproductive efficiency of the traditional propensity to a large family size is therefore examined by means of two different evaluations of reproductive success: the 'absolute' reproductive success (the absolute number of offspring surviving to maturity) and the 'relative' reproductive success (the proportion of live born surviving to maturity). The first shows that close pregnancies increase the fertility rate to such an extent that the associate higher number of deaths is more than compensated for, so that the women practising short birth intervals produce more surviving offspring than the others by the end of their reproductive life. The second shows that the probability of survival is directly associated with birth interval length, the efficiency of the reproductive process being therefore greater as birth intervals grow. It is suggested that these two behaviours are not contradictory, and that they represent two successive steps of the same reproductive adjustment to evolving environmental conditions.

Aged↗

PubMed1999

IPPF Charter on Sexual and Reproductive Rights. International Planned Parenthood Federation.

For most of human existence and in most societies, women have been considered to be property and subject to men. Throughout history, with such notable exceptions as Queen Boadicea, Eleanor of Aquitaine, Elizabeth I of England, and Catherine the Great of Russia, women had little or no power until early in the 20th century when the women's suffrage movement was successful in the United States and in some European countries. As women have gained political rights, groups of women have sought sexual and reproductive rights, as exemplified by the feminist movement of the past few decades in the United States. Although marked strides toward achievement of reproductive choice have been taken in high-income countries, there remain major strictures to reproductive freedom for women in low-income countries. This area, which is replete with ethical and moral issues, has been addressed by the International Planned Parenthood Foundation (IPPF), which has worked to improve the sexual and reproductive health of women throughout the world. The IPPF Charter on Sexual and Reproductive Rights is a paradigm for both women's rights and human rights. Karen Newman is policy adviser with the IPPF and has codrafted the IPPF Charter on Sexual and Reproductive Rights together with two lawyers. She has held several positions within the IPPF, including medical researcher, press officer, and programme adviser in Europe, where she had responsibility for working with new family planning associations (FPAs) in the Czech Republic and Slovakia. At present, she is working to increase the capacity of IPPF member FPAs to undertake human rights-based advocacy for sexual and reproductive health and rights. Judith F. Helzner is director of Sexual and Reproductive Health at International Planned Parenthood Federation/Western Hemisphere Region, Inc., where she has worked since 1987. She holds M.A. degrees from the University of Pennsylvania in International Relations and Demography. Her previous employment includes the Pathfinder Fund and the International Women's Health Coalition.

Family Planning Services↗

PubMed2003

Research in nondomestic species: experiences in reproductive physiology research for conservation of endangered felids.

Tremendous strides have been made in recent years to broaden our understanding of reproductive processes in nondomestic felid species and further our capacity to use this basic knowledge to control and manipulate reproduction of endangered cats. Much of that progress has culminated from detailed scientific studies conducted in nontraditional laboratory settings, frequently at collaborating zoological parks but also under more primitive conditions, including in the field. A mobile laboratory approach is described, which incorporates a diverse array of disciplines and research techniques. This approach has been extremely useful, especially for conducting gamete characterization and function studies as well as reproductive surveys, and for facilitating the development of assisted reproductive technology. With continuing advances in assisted reproduction in rare felids, more procedures are being conducted primarily as service-related activities, targeted to increase effectiveness of species propagation and population management. It can be a challenge for both investigators and institutional animal care and use committees (IACUCs) to differentiate these service-based procedures from traditional research studies (that require IACUC oversight). For research with rare cat species, multi-institutional collaboration frequently is necessary to gain access to scientifically meaningful numbers of study subjects. Similarly, for service-based efforts, the ability to perform reproductive procedures across institutions under nonstandard laboratory conditions is critical to applying reproductive sciences for managing and preserving threatened cat populations. Reproductive sciences can most effectively assist population management programs (e.g., Species Survival Plans) in addressing conservation priorities if these research and service-related procedures can be conducted "on the road" at distant national and international locales. This mobile laboratory approach has applications beyond endangered species research, notably for other scientific fields (e.g., studies of hereditary disease in domestic cat models) in which bringing the laboratory to the subject is of value.

Animals↗

PubMed2026

Comparative Transcriptomic Analyses Identify Candidate Genes for Convergent Reproductive Shifts in a Bimodal Viviparous Amphibian.

Shifts in reproductive mode represent key evolutionary innovations that shape species' life histories and evolutionary trajectories. Species showing bimodal reproductive strategies with multiple independent origins offer a rare opportunity to gain insights into the adaptive processes and mechanisms underlying convergent traits. The fire salamander, Salamandra salamandra, is the only amphibian exhibiting intraspecific variation in reproductive mode across multiple independent reproductive shifts, enabling investigation of the transition between larviparity (females give birth to aquatic larvae) and pueriparity (females give birth to fully developed terrestrial juveniles) within a single species and across different timescales. Pueriparity is an adaptive innovation that skips the aquatic larval stage, allowing individuals to exploit habitats with no available water bodies. The fire salamander is larviparous across most of its range, but pueriparity has evolved independently at least three times: once in the early Pleistocene within S. s. bernardezi in the mountains of northern Spain, and more recently on two land-bridge islands (NW Spain) inhabited by S. s. gallaica. To identify candidate genes associated with these distinct reproductive modes, we compared gene expression profiles of the uterus and oviduct of pregnant females across two independent evolutionary transitions using RNA-sequencing. We detected shared changes in maternal gene expression among pueriparous S. s. bernardezi and S. s. gallaica relative to their larviparous counterparts, in addition to differences unique to each independent evolutionary transition. Functional enrichment analyses indicated that differentially expressed genes were associated with reproductive timing, angiogenesis, and maternal signalling, consistent with the phenotypic differences observed in the uterine environment and embryonic development between the two reproductive modes. This study represents an important first step towards understanding the genomic basis of the evolution of pueriparity in a remarkable bimodal reproductive system, and provides transcriptomic resources and candidate genes for future research into the genomic architecture underlying this poorly understood adaptive trait.

Animals↗

PubMedDate not supplied

Unmanaged care: the need to regulate new reproductive technologies in the United States.

In the aftermath of allegations of the misuse of human eggs in the United States, questions are being raised about whether profitable reproductive services should continue to function in a free market under the aegis of physicians or should be regulated. Other countries in which reproductive technologies are employed to a significant degree have developed regulations governing their use, many as a result of recommendations made by inter-disciplinary commissions that solicited public input. Policy makers in the United States have been reluctant to regulate reproductive technologies, however, because their use is politically controversial, they want to whittle down government, some do not consider infertility an illness, and some believe regulation would interfere with the right to reproduce. Yet the unfettered use of reproductive technologies can create such harms as lack of informed consent, providing procedures not medically indicated for financial gain, practice by unqualified personnel, injury to patients and donors, failure to screen donated gametes, and inadequate medical record keeping. Americans place special value on the welfare of children and those who bring them into the world. Such values can outweigh individual procreative liberty when new reproductive technologies are at issue. Although the optimal course would be to establish a regulatory body to govern reproductive technologies, this is not politically feasible now. The newly established National Bioethics Advisory Commission provides a forum in which issues surrounding reproductive technologies should be addressed at this time in the United States.

Advisory Committees↗

PubMed1997

Criteria of reproductive success.

To determine reproductive success, it is necessary for the researcher to specify a criterion of success, such as the number of a parent's offspring living to the age of reproduction. A measurement model, which includes the researcher's choice of criterion, has been proposed to estimate the lifetime reproductive success (R) of long-lived animals from complete or incomplete knowledge of the reproductive life histories of mothers and the survival fates of offspring. This research uses R and data from female baboons of Mikumi National Park, Tanzania, as vehicles to investigate the relationship between reproductive success and several criteria. Secondarily, it also investigates the relationship between R and the number and rate of offspring production. Seven criteria of reproductive success, ranging in 12-month increments form 0 (birth) to 72 months of offspring life, were applied to 10.5 years of reproductive data from 61 Mikumi females. Theoretically, the best scenario for comparative purposes is an invariant R across different criteria; however, the mean R systematically increased as the criteria increased. This is more an inconvenience than a serious problem because high correlations indicate high predictability between Rs from pairs of criteria. R was modestly correlated with the rate of offspring production, indicating that rate can be employed as a rough index of reproductive success. The choice of a criterion is a trade off between theory, practicality, the strength of the criterion, and the effect of the choice upon sample representativeness and size.

Animals↗

PubMedDate not supplied

Somatic versus reproductive energy allocation in Papua New Guinea: life history theory and public health policy.

A fundamental evolutionary problem faced by organisms is how to allocate energy to somatic and reproductive functions in ways that optimize fitness. Given that energy is limited in all environments, energy allocation necessarily involves physiological tradeoffs between such factors as growth and reproduction, reproduction and condition, and current reproduction and future survival. Ultimately, the "decisions" that are made about energy allocation among growth, survival, and reproduction determine life history patterns and trajectories of organisms. For humans, knowing how energy allocation to reproduction will likely impact other aspects of the somatic well-being of individuals may also have practical implications for public health policy. This article reviews the evidence for energy tradeoffs between somatic and reproductive functioning in a range of human societies. It also seeks to corroborate the results of earlier work in Papua New Guinea on lactation-related maternal energy depletion using an independent measure of maternal energy reserves, tetrapolar bioelectrical impedance analysis. The current analysis shows that maternal energy reserves decline over the course of lactation and that a cumulative parity-specific decline in maternal energy reserves also exists. A longitudinal follow-up of five women over 11 years shows the decline to amount to about 3 mm of subcutaneous fat per round of pregnancy and lactation. The results corroborate predictions from life history theory and have applied public health implications. In particular, It is suggested that policies such as lactation advocacy that encourage enhanced energy allocation to reproduction in order to promote child health may have the unintended result of compromising maternal well-being, particularly in nations of the developing world. Consequently, it is recommended that nutritional support of mothers be implemented in concert with lactation promotion.

Body Composition↗

PubMed1983

Relevance of parameters related to fertility and reproduction in toxicity testing.

Toxicity data of 37 compounds tested in both a subchronic study and one or more studies focused on reproduction were evaluated to obtain information on the significance of fertility and reproduction parameters in setting no-effect levels (NEL). It appeared that a) the test system aimed at reproduction and development was more sensitive than the subchronic study for 35% of the selected compounds and was equally sensitive for another 35%; b) for 65% of these compounds parameters related to reproduction and development were at least codecisive in determining the minimal-effect level (MEL); c) for 21% of all compounds, parameters related to reproduction were the most sensitive and therefore decisive for the MEL. It was concluded that reproduction in its broadest sense is a very sensitive tool in toxicity testing. The possibilities of either applying a simple screen of fertility and reproduction at an early stage of toxicity testing or incorporating fertility and reproduction parameters in the current subchronic study are discussed.

Animals↗

PubMed1990

Teleost model for studying the effects of chemicals on female reproductive endocrine function.

The effects of several mammalian reproductive toxins on reproductive endocrine function in female Atlantic croaker (Micropogonias undulatus) were examined. Croaker were exposed to sublethal concentrations of lead, cadmium, benzo[a]pyrene (BaP), or a polychlorinated biphenyl mixture (Aroclor 1254) for 1 month during the period of ovarian recrudescence. Reproduction was altered after exposure to all four chemicals. The plasma levels and secretion rates of reproductive hormones were augmented after exposure to cadmium resulting in precocious ovarian growth. In contrast, treatment with lead, BaP, or Aroclor 1254 caused a decline in circulating steroid hormone levels and ovarian growth. Changes in hormone secretion rates from isolated pituitary and ovarian tissues incubated in vitro were also observed after exposure to several of the reproductive toxins. It is concluded that the Atlantic croaker is a sensitive model for examining the effects of reproductive toxins on female reproductive endocrine function. Our results indicate that these chemicals may act at various sites on the hypothalamus-pituitary-gonadal axis to alter reproductive endocrine function.

Animals↗