Preliminary investigation reveals novel pathological consequences of bluetongue virus-1 infection in the endocrine glands of pregnant Indian sheep

Bluetongue virus (BTV), a major peril to the sheep industry, infects a wide range of the cells in the infected animals including mononuclear, dendritic and epithelial cells. However, little is known about its tropism for the secretory epithelial cells of endocrine glands and the pathogenesis it induces. The aim of the study was to assess the BTV load, antigen distribution in the tissue of the pituitary, thyroid as well as adrenal glands and associated histopathological consequences. BTV antigens were localized using immunohistochemistry in the thyroid's epithelial cells, zona fasciculata and zona reticularis cells and the anterior pituitary epithelial cells. The real-time PCR portrayed the high viral load in adrenals at 7th days postinoculation (DPI) and in thyroid and pituitary glands at 15th DPI. Serum examination revealed variation in the T-3 and T-4 of infected animals in comparison to the control group. Caspase-3 immunolocalization revealed BTV-1 induces apoptosis in the affected cells of endocrine gland of infected animals. Further, this study signifies the tropism of BTV in the novel sites (endocrine glands) of the host that might be one of the reasons for the poor performance of infected animals.

[Characterization of Endocrine Glands Involved in Erdheim-Chester Disease]

Objective To investigate the clinical and imaging characteristics of endocrine glands involved in Erdheim-Chester disease (ECD).Methods A retrospective analysis was performed on 48 ECD cases pathologically diagnosed from January 2014 to October 2020 in Peking Union Medical College Hospital,including 22 cases of endocrine gland involvement.The clinical,imaging,and pathological characteristics were summarized. Results Pituitary was involved in 17 cases (17/48,35.4%),adrenal gland in 8 cases (8/48,16.7%),and both pituitary and adrenal gland in 3 cases (3/48,6.25%).The most common symptom in patients with pituitary involvement was central diabetes insipidus (13/17,76.5%),and the T1-weighted imaging showed posterior pituitary hypersignal disappearance,pituitary stalk thickening,and abnormally enhanced pituitary nodules.The most common symptom in patients with adrenal gland involvement was adrenal function reduction (3/8,37.5%),and the CT scanning showed diffuse thickening of adrenal glands.BRAF V600E mutation was positive in 13 (13/22,59.1%) cases with ECD involving endocrine glands.Conclusion Pituitary and adrenal glands are the most common sites of ECD involving endocrine glands.A definite diagnosis can be achieved by combining clinical,imaging,and pathological characteristics for timely treatment.

Beyond Premature Ovarian Insufficiency: Staging Reproductive Aging in Adolescent and Young Adult Cancer Survivors

CONTEXT

Although stages of reproductive aging for women in the general population are well described by STRAW+10 criteria, this is largely unknown for female adolescent and young adult cancer survivors (AYA survivors).

OBJECTIVE

This work aimed to evaluate applying STRAW + 10 criteria in AYA survivors using bleeding patterns with and without endocrine biomarkers, and to assess how cancer treatment gonadotoxicity is related to reproductive aging stage.

DESIGN

The sample (n = 338) included AYA survivors from the Reproductive Window Study cohort. Menstrual bleeding data and dried-blood spots for antimüllerian hormone (AMH) and follicle-stimulating hormone (FSH) measurements (Ansh DBS enzyme-linked immunosorbent assays) were used for reproductive aging stage assessment. Cancer treatment data were abstracted from medical records.

RESULTS

Among participants, mean age 34.0 ± 4.5 years and at a mean of 6.9 ± 4.6 years since cancer treatment, the most common cancers were lymphomas (31%), breast (23%), and thyroid (17%). Twenty-nine percent were unclassifiable by STRAW + 10 criteria, occurring more frequently in the first 2 years from treatment. Most unclassifiable survivors exhibited bleeding patterns consistent with the menopausal transition, but had reproductive phase AMH and/or FSH levels. For classifiable survivors (48% peak reproductive, 30% late reproductive, 12% early transition, 3% late transition, and 7% postmenopause), endocrine biomarkers distinguished among peak, early, and late stages within the reproductive and transition phases. Gonadotoxic treatments were associated with more advanced stages.

CONCLUSIONS

We demonstrate a novel association between gonadotoxic treatments and advanced stages of reproductive aging. Without endocrine biomarkers, bleeding pattern alone can misclassify AYA survivors into more or less advanced stages. Moreover, a large proportion of AYA survivors exhibited combinations of endocrine biomarkers and bleeding patterns that do not fit the STRAW + 10 criteria, suggesting the need for modified staging for this population.

Imaging endocrinology in animal models of endocrine disease

Endocrine organs secrete a variety of hormones involved in the regulation of a multitude of body functions. Although pancreatic islets were discovered at the turn of the 19th century, other endocrine glands remained commonly described as diffuse endocrine systems. Over the last two decades, development of new imaging techniques and genetically-modified animals with cell-specific fluorescent tags or specific hormone deficiencies have enabled in vivo imaging of endocrine organs and revealed intricate endocrine cell network structures and plasticity. Overall, these new tools have revolutionized our understanding of endocrine function. The overarching aim of this Review is to describe the current mechanistic understanding that has emerged from imaging studies of endocrine cell network structure/function relationships in animal models, with a particular emphasis on the pituitary gland and the endocrine pancreas.

[Polyglandular autoimmune syndromes : An overview]

Polyglandular autoimmune syndromes (PGAS), also known as autoimmune polyendocrinopathy syndromes (APS), are a heterogeneous group of rare, genetically caused diseases of the immune system which lead to inflammatory damage of various endocrine glands resulting in malfunctions. In addition, autoimmune diseases of non-endocrine organs may also be found. Early diagnosis of PGAS is often overlooked because of heterogeneous symptoms and the progressive occurrence of the individual diseases. The two most important forms of PGAS are the juvenile and adult types. The juvenile type (PGAS type 1) is caused by mutations in the autoimmune regulator (AIRE) gene on chromosome 21, exhibits geographic variations in incidence and is defined by the combination of mucocutaneous candidiasis, Addison's disease and hypoparathyroidism. In addition, autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) syndrome and other autoimmune diseases can also occur. The adult form of PGAS (PGAS type 2) is a multigenetic disorder associated with some HLA haplotypes, is more common than the juvenile type, shows female predominance and exhibits the combination of type 1 diabetes, autoimmune thyroid disease, Addison's disease and other autoimmune disorders. The histological alterations in affected organs of PGAS patients are similar to findings in sporadically occurring autoimmune diseases of these organs but there are no pathognomic fine tissue findings. If patients exhibit autoimmune changes in two different endocrine glands or if there are indications of several autoimmune disorders from the patient history, it is important to consider PGAS and inform the clinicians of this suspicion.

Endocrine Manifestations in a Monocentric Cohort of 64 Patients With Erdheim-Chester Disease

CONTEXT

Erdheim-Chester disease (ECD) is a rare non-Langerhans cell histiocytosis, characterized by infiltration of foamy histiocytes in multiple organs. Endocrine involvement has mostly been described in case reports.

OBJECTIVE

We performed systematic endocrine evaluation in a large cohort of patients with ECD.

DESIGN

This was a single-center observational study conducted between October 2007 and May 2013.

SETTING

The evaluation was conducted in Pitié-Salpêtrière Hospital (Paris, France), a tertiary care hospital.

PATIENTS

Sixty-four consecutive patients with ECD (sex ratio, 3.6; mean age, 57.6 years [range, 20-80 years]). Thirty-six patients had follow-up assessments.

INTERVENTIONS

There were no interventions.

MAIN OUTCOME MEASURES

Clinical, biological, and morphological evaluations of pituitary, gonadal, adrenal, and thyroid functions, as well as metabolic evaluation, were performed.

RESULTS

Diabetes insipidus was found in 33.3% of patients, frequently as the first manifestation of ECD. Anterior pituitary dysfunction was found in 91.3% of patients with full anterior pituitary evaluation, including somatotropic deficiency (78.6%), hyperprolactinemia (44.1%), gonadotropic deficiency (22.2%), thyrotropic deficiency (9.5%), and corticotropic deficiency (3.1%). Thirty-five patients (54.7%) had ≥2 anterior pituitary dysfunctional axes, rising to 69.6% (16 of 23) when only patients with complete evaluations were considered. Two patients had panhypopituitarism. Infiltration of the pituitary and stalk was found with magnetic resonance imaging in 24.4% of patients. Testicular insufficiency was found in 53.1% of patients, with sonographic testicular infiltration in 29% of men, mostly bilateral. Computed tomography adrenal infiltration was found in 39.1% of patients, and 1 case of adrenal insufficiency was observed. No patient was free of endocrine hormonal or morphological involvement. Endocrine dysfunctions were most often permanent, and new deficits appeared during follow-up.

CONCLUSION

Endocrine involvement is very frequent in ECD and should be evaluated carefully at diagnosis and during follow-up.

Hyperplasia in glands with hormone excess

Five syndromes share predominantly hyperplastic glands with a primary excess of hormones: neonatal severe primary hyperparathyroidism, from homozygous mutated CASR, begins severely in utero; congenital non-autoimmune thyrotoxicosis, from mutated TSHR, varies from severe with fetal onset to mild with adult onset; familial male-limited precocious puberty, from mutated LHR, expresses testosterone oversecretion in young boys; hereditary ovarian hyperstimulation syndrome, from mutated FSHR, expresses symptomatic systemic vascular permeabilities during pregnancy; and familial hyperaldosteronism type IIIA, from mutated KCNJ5, presents in young children with hypertension and hypokalemia. The grouping of these five syndromes highlights predominant hyperplasia as a stable tissue endpoint and as their tissue stage for all of the hormone excess. Comparisons were made among this and two other groups of syndromes, forming a continuum of gland staging: predominant oversecretions express little or no hyperplasia; predominant hyperplasias express little or no neoplasia; and predominant neoplasias express nodules, adenomas, or cancers. Hyperplasias may progress (5 of 5) to neoplastic stages while predominant oversecretions rarely do (1 of 6; frequencies differ P<0.02). Hyperplasias do not show tumor multiplicity (0 of 5) unlike neoplasias that do (13 of 19; P<0.02). Hyperplasias express mutation of a plasma membrane-bound sensor (5 of 5), while neoplasias rarely do (3 of 14; P<0.002). In conclusion, the multiple distinguishing themes within the hyperplasias establish a robust pathophysiology. It has the shared and novel feature of mutant sensors in the plasma membrane, suggesting that these are major contributors to hyperplasia.

[EFFICACY OF WELDING TECHNOLOGY AS A PRINCIPAL METHOD OF DISSECTION AND HEMOSTASIS IN ENDOCRINAL SURGERY]

Today in the clinic all surgical interventions on endocrinal organs are conducted, using welding technology. Comparative analysis of the operative interventions efficacy, performed applying a standard method (control group) and using welding technology (the main group), was conducted. Performance of operations, using electric welding technologies have permitted to reduce the operative intervention duration by 20 - 30%, the blood loss volume--by 30 - 50%, a postoperative pain syndrome severity and the analgetics expense--by 20%, a postoperative stationary treatment duration--by 1-2 days.

Next generation sequencing in endocrine practice

With the completion of the Human Genome Project and advances in genomic sequencing technologies, the use of clinical molecular diagnostics has grown tremendously over the last decade. Next-generation sequencing (NGS) has overcome many of the practical roadblocks that had slowed the adoption of molecular testing for routine clinical diagnosis. In endocrinology, targeted NGS now complements biochemical testing and imaging studies. The goal of this review is to provide clinicians with a guide to the application of NGS to genetic testing for endocrine conditions, by compiling a list of established gene mutations detectable by NGS, and highlighting key phenotypic features of these disorders. As we outline in this review, the clinical utility of NGS-based molecular testing for endocrine disorders is very high. Identifying an exact genetic etiology improves understanding of the disease, provides clear explanation to families about the cause, and guides decisions about screening, prevention and/or treatment. To illustrate this approach, a case of hypophosphatasia with a pathogenic mutation in the ALPL gene detected by NGS is presented.

Correlated analysis and pathological study on insulin resistance and cardiovascular endocrine hormone in elderly hypertension patients

AIMS

The correlated analysis and pathological study on insulin resistance and cardiovascular endocrine hormone in elderly hypertension patients was investigated by clinical observation and physical experiments in my hospital.

MATERIALS AND METHODS

Randomly enrolled 300 subjects seen at hospital from January 2011 to January 2013, which included 150 hypertension patients and 150 non-hypertension of healthy people, while 150 cases of hypertension patients as the experimental group, 150 cases of healthy people without hypertension acts as the control group. The t-PA of serum (plasma), activity of PAI, ANP, IS, ET were determined in this 300 subjects, and it studied on the correlation and pathological effect between insulin resistance and cardiovascular endocrine hormone in elderly hypertension patients.

RESULTS

The levels of PAI, ANP, ET are apparently higher in hypertension patients than in healthy control group (p<0.05), while the t-PA, IS are obviously lower in hypertensive patients than in healthy control group (p>0.05).

CONCLUSION

This study has shown that there is a significant correlation and pathological effect between insulin resistance and cardiovascular endocrine hormone in hypertensive patients, and which plays an important role in genesis and development of hypertension in elderly people.

Long-term storage of endocrine tissues at - 80°C does not adversely affect RNA quality or overall histomorphology

BACKGROUND

Today, no consensus exists regarding how human tissues are best preserved for long-term storage. Very low temperature storage in liquid nitrogen is often advocated as the superlative method for extended periods, but storage in -80 degrees Celsius (-80°C) freezers, while sometimes debated, is a possible alternative. RNA is the most easily degradable component of a biological sample in a molecular biology context and the quality can reliably be measured.

AIM

To investigate to what extent long-term storage of tissues in -80°C affects the RNA quality and overall histomorphology. The tissue storage period represents nearly three decades (1986-2013).

METHODS

RNA extraction from 153 tissue samples with different storage periods was performed with the mirVana kit (Invitrogen). RNA integrity was assessed using an Agilent bioanalyzer to obtain RNA integrity numbers (RIN). Further, tissue representative testing using light microscopy was performed by two pathologists to assess tissue composition and morphology.

RESULTS

RIN values were measured in all samples, showing a variability that did not correlate with the storage time of the tissues. Microscopically, all samples displayed acceptable tissue morphology regardless of storage time.

CONCLUSION

Long-term storage in -80°C does not adversely affect the quality of the RNA extracted from the stored tissues, and the tissue morphology is maintained to a good standard.

Perspectives in endocrine toxicity of heavy metals--a review

An attempt has been made to review the endocrine/hormonal implications of a few environmentally significant metals, viz, lead, mercury, cadmium, copper, arsenic and nickel, in man and animals. Special emphasis has been given to the adrenals, thyroid, testis, ovary and pancreas. Toxic metals can cause structural and functional changes in the adrenal glands. Their effects on steroidogenesis have been reviewed. It has been reported that thyroid hormone kinetics are affected by a number of metallic compounds. Occupational exposure to a few of these metals can cause testicular injury and sex hormone disturbances. Protective effects of a few antioxidants on their reproductive toxicity have also been discussed. Information gathered on female reproductive toxicity of heavy metals shows that exposure to these metals can lead to disturbances in reproductive performance in exposed subjects. Certain metals can cause injury to the endocrine pancreas. Exposure to them can cause diabetes mellitus and disturb insulin homeostasis. The need to develop molecular markers of endocrine toxicity of heavy metals has been suggested. Overall information described in this review is expected to be helpful in planning future studies on endocrine toxicity of heavy metals.

Endocrine histology findings in a prepubertal thalassemic girl with multiple endocrine complications secondary to iron overload

β-thalassaemia major (TM) is an inherited disorder of erythropoiesis requiring regular blood transfusions and chelation therapy for the iron overload resulting from transfusions and increased gastrointestinal absorption. Endocrine dysfunctions are common in older children with TM and has been attributed to iron deposition in endocrine glands. The Authors report the clinical and histological findings of endocrine glands in a prepubertal girl with multiple endocrine complications secondary to iron overloadn died from cardiac failure. Variations in severity of the disease and therapeutic regimens may result in different incidence and types of complications It is emphasized the importance of chelating therapy to protect endocrine glands from haemosiderosis.

Endocrine organs under the control of the immune system: potential implications for cellular therapies

Within the last couple of years much knowledge has been gained in understanding the immune interactions in endocrine diseases including endocrine malignancies and autoimmune diseases. The major players within the innate immune system represent NK cells. This review describes that these cells directly lyse tumor cells and promote the activity of other cells of the immune system, including dendritic cells (DCs), macrophages, Th1 cells, and cytotoxic T-lymphocytes (CTLs). NK cells may also be involved in the initiation of autoimmunity as they may accumulate in target organs of certain autoimmune diseases. On the other hand, there are cells of the adaptive immune system including antigen-presenting DCs and T cells with helper and effector function, which are responsible for a directed immune response. Within this review, we present an overview on the role of all these cell populations in endocrine disease and the potential use of such cells for immunotherapy in different endocrine diseases and refer to experimental settings as well as clinical studies.

[Comparative morphological analysis of peripheral endocrine glands in small mammals inhabiting areas with high levels of radioactive pollutants and exposed to chronic irradiation in laboratory experiments]

The comparative study of cellular-tissue reactions in endocrine organs (thyroid and suprarenal glands, ovary) of rodents exposed to radiation in natural conditions (Radium station in Komi Republic and 30-km zone of Chernobyl APP) and experimental conditions modeling the chronic exposure has been conducted. There is evidence that chronic irradiation in low doses causes morphological disorders in different levels of structural organization (cellular-tissue, organism and population levels). The experimental results showed that observed variations in thyroid, suprarenal glands and ovary by morphometric parameters reflect the natural changes in their functional activity (within the physiological limits). These changes are directed at the homeostasis maintenance in changed conditions and have a compensatory and adaptation character. The effects of low dose radiation influence with combination of other agents may be amplified at the cellular-tissue reactions level. In comparison with experimental results, the natural conditions (high level of radioactivity with alpha- and beta-emitters, high natural radionuclides, toxic elements and extreme climatic factors) induce more expressed changes as a significant increasing of chromosomal and genes mutations in cells, destructive processes in organs of endocrine system and disorders of reproductive functions.

[Comparative morphological characteristic of immune deficiency in subjects with opioid addiction and chronic alcoholic intoxication]

The objective of the present study was to analyse changes of morphological properties in the organs of immune and endocrine systems in subjects with opioid addiction and chronic alcoholic intoxication (CAI) based on the results of 322 autopsies. These included 190 cases of drug addiction from 0.5 to 10.5 years in duration, 90 cases of chronic alcoholic intoxication, 42 cases of combined drug addiction and CAI. The study demonstrated phasic character of changes in the organs of immune and endocrine systems in subjects with opioid addiction. Three phases were distinguished in the development of immune and endocrine disorders (secondary immunodeficiency syndrome) that correspond to the stages of formation, compensation, and decompensation, respectively, of general adaptation syndrome as a reaction to chronic stress. These processes may be deranged in case of combination of opioid addiction and CAI when changes in the immune and endocrine systems resemble those observed in severe immunodeficiency with serious atrophic and sclerotic lesions in lymphoid organs and endocrine glands. Characteristics of immune deficiency resulting from the consumption of narcotic substances and chronic alcoholic intoxication have much in common even though either of the two underlying conditions shows certain specific features.

[Prognostic, diagnostic, and therapeutic prospects of using adiponectine as a biomarker in cardiobascular diseases]

The role of adipose tissue as an important endocrine organ is today beyond doubt. The adipose tissue is known to be a source of many biologically active substances, adipocitokines, one of them being the adiponectine possessing anti-inflammatory, antiatherogenic and cardioprotective properties; it is believed to be one of prospective biomarkers for risk assessment, for diagnostics and, possibly, for therapy of cardiovascular diseases.

A critical comparison of murine pathology and epidemiological data of TCDD, PCB126, and PeCDF

2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD, or dioxin) and dioxin-like compounds (DLCs) induce numerous toxicities, including developmental, endocrine, immunological, and multi-organ carcinogenic, in animals and/or humans. Multiple studies completed by the National Toxicology Program (NTP) focused on the effects caused in Harlan Sprague-Dawley rats by specific DLCs, among them the prototypical dioxin, TCDD. Because humans are exposed daily to a combination of DLCs, primarily via ingestion of food, the Toxic Equivalency Factor (TEF) was developed in order to evaluate health hazards caused by these mixtures. Herein we review the pathological effects reported in humans exposed to TCDD; 3,3',4,4',5-pentachlorobiphenyl (PCB 126); and 2,3,4,7,8,-pentachlorodibenzofuran (PeCDF) and compare them to similar changes seen in NTP murine studies performed with the same compounds. While there were differences in specific pathologies observed, clear consistency in the target organs affected (liver, oral cavity, cardiovascular system, immune system, thyroid, pancreas, and lung) could be seen in both human studies and rodent toxicity and carcinogenicity investigations.

Gastric and intestinal phenotypic correlation between exocrine and endocrine components in human stomach tumors

We have previously suggested that an origin of a stomach cancer is from a progenitor cell specializing toward exocrine cell (Exo-cell) lineages. To clarify whether our hypothesis is correct or not, we analyzed the expression of Exo-cell and endocrine cell (End-cell) markers in a series of lesions for comparison. We evaluated chromogranin A (CgA) expression in 37 early and 73 advanced stomach cancers, in 30 stomach adenomas, in 8 carcinoid tumors, and in 4 endocrine cell carcinomas (ECCs) with assessment of gastric and/or intestinal (G/I) phenotypes in both Exo-cell and End-cell by immunohistochemistry. CgA expression was observed in 10.8% of the early and 16.4% of the advanced stomach cancers, respectively. The End-cell G/I phenotypes were in line with the Exo-cell counterparts in the CgA-positive stomach cancerous areas, and there was strong association between Cdx2 expression and the intestinal End-cell markers. All of the adenoma cases had the intestinal Exo-cell phenotypic expression, with the positive link between Exo-cell and End-cell G/I phenotypes. All stomach carcinoids had CgA expression but no expression of Exo-cell markers. In conclusion, most stomach cancers might develop from a progenitor cell specializing towards Exo-cell lineages, but some cases possessed both Exo-cell and End-cell markers with maturely differentiated phenotypes. In such cases, Exo-cell and End-cell phenotypes were found to correlate strongly, suggesting the possibility of histogenesis from "cancer stem cells".

Intersex in the clam Scrobicularia plana: a sign of endocrine disruption in estuaries?

The phenomenon of endocrine disruption is currently a source of growing concern. Feminization of male fish in UK rivers has been shown to occur extensively and has been linked with exposure to endocrine-disrupting compounds present in the environment. Much less is known of the extent and scale of endocrine disruption in estuarine and marine ecosystems, particularly in invertebrates. We present evidence that intersex, in the form of ovotestis, is occurring in the common estuarine bivalve Scrobicularia plana, which is considered to be inherently gonochoristic. We report varying degrees in the severity of ovotestis in male S. plana, and have adopted and developed a grading method to assess the extent of this intersex condition. These findings indicate that S. plana offers potential for widespread screening and investigation of endocrine disruption, helping to focus remediatory strategy.

Obesity, inflammation, and vascular disease: the role of the adipose tissue as an endocrine organ

Insulin resistance, both in nondiabetic and diabetic subjects, is frequently associated with obesity, particularly with an excess of central fat. With the growing prevalence of obesity, scientific interest in the biology of adipose tissue has been extended to the secretory products of adipocytes, since they are increasingly shown to influence several aspects in the pathogenesis of obesity-related diseases Until relatively recently, the role of fat itself in the development of obesity and its consequences was considered to be a passive one; adipocytes were considered to be little more than storage cells for fat. It is now clear that, in addition to storing calories as triglycerides, they also secrete a large variety of proteins, including cytokines, chemokines and hormone-like factors, such as leptin, adiponectin and resistin. This production of pro-atherogenic chemokines by adipose tissue is of particular interest since their local secretion, e.g. by perivascular adipose depots, may provide a novel mechanistic link between obesity and the associated vascular complications. Recent research has revealed many functions of adipocytokines extending far beyond metabolism, such as immunity, cancer and bone formation. This remarkable understanding is allowing us to more clearly define the role that adipocytes play in health and in obesity and how inflammatory mediators act as signaling molecules in this process. Moreover, on a molecular level, we are beginning to comprehend how such variables as hormonal control, exercise, food intake, and genetic variation interact and result in a given phenotype, and how pharmacological intervention may modulate adipose tissue biology.

Helicobacter pylori infection stimulates intestinalization of endocrine cells in glandular stomach of Mongolian gerbils

Intestinal metaplasia has been investigated extensively as a possible premalignant condition for stomach cancer but its pathogenesis is still not fully understood. In the present study, we examined the relationship between endocrine and mucous cell marker expression periodically after Helicobacter pylori infection in the Mongolian gerbil model. The numbers of chromogranin A (CgA)-positive, gastrin-positive and gastric inhibitory polypeptide (GIP)-positive cells in H. pylori-infected groups was increased significantly compared with the non-infected case. However, CgA-positive and gastrin-positive cells then decreased from 50 through 100 experimental weeks after H. pylori infection, whereas GIP-positive cells increased. Coexistence of gastrin-positive and GIP-positive cells was detected in the same gastric and intestinal mixed phenotypic glandular-type glands. In conclusion, the endocrine cell phenotype is in line with that of the mucous counterpart in the glands of H. pylori-infected Mongolian gerbil stomach, supporting the concept that development of intestinal metaplasia is due to the abnormal differentiation of a stem cell.

Treatment of alternated water-electrolyte balance and endocrine status after removal of craniopharyngioma in adults

BACKGROUND

Water-electrolyte disturbance and endocrine alterations are common complications of adult patients with craniopharygioma in the postoperative period and may affect their recovery and prognosis. Some of these complications even lead to death. Appropriate remedy based upon the status of water-electrolyte balance and the endocrine system is essential to good therapeutic results of adult patients with craniopharyngioma.

METHODS

The alterations in water-electrolyte balance (117 patients) and endocrine status (42) of adult patients with craniopharyngioma after surgery were analyzed retrospectively.

RESULTS

Most patients with craniopharyngioma experienced postoperative water-electrolyte disturbances and hypotonic dehydration. Moreover, the incidences of hypothyroidism and hypoadrenocorticism were relatively high.

CONCLUSION

It is critical to deal with dehydration and endocrine disorders for a sound outcome of craniopharyngioma surgery.

A repeated 28-day oral dose toxicity study of nonylphenol in rats, based on the 'Enhanced OECD Test Guideline 407' for screening of endocrine-disrupting chemicals

A 28-day repeated oral dose toxicity study of nonylphenol (NP) was performed for an international validation of the 'Enhanced OECD Test Guideline 407' paying particular attention to the sensitivity of individual endocrine-related parameters. Sprague-Dawley rats, each group consisting of ten males and ten females, were administered NP once daily by gavage at doses of 0 (control), 10, 50, or 250 mg/kg body weight. At 250 mg/kg, three females died or became moribund during the experiment. At this dose, hepatic and renal toxicity was evident in both sexes with increase of relative liver and kidney weights as well as histopathological changes, such as centrilobular liver cell hypertrophy and a variety of renal tubular lesions, and alteration of serum biochemical parameters, some of them being evident from 50 mg/kg in females (glucose and inorganic phosphates). Hematologically, development of anemia was evident at 250 mg/kg in both sexes. Regarding endocrine-related effects, increase of thyroid weight in males was detected from 50 mg/kg. At 250 mg/kg, males exhibited reduction of relative weights of the ventral prostate and seminal vesicles, and females developed irregular estrous cyclicity and vaginal mucosal hyperplasia. Although changes in serum hormone levels were detected in both sexes, magnitude of the changes was small to be regarded as a low toxicological significance. In summary, repeated oral doses of NP to rats for 28 days resulted in hepato-renal toxicity from 50 mg/kg and anemia at 250 mg/kg. Effects on the endocrine system were observed from 50 mg/kg, and assessment of weights and histopathology of endocrine-related organs and estrous cyclicity may be valid in a battery for detecting endocrine effects of NP. The no-observed-adverse-effect level of NP was estimated to be 10 mg/kg per day.

Fat as an endocrine organ: relationship to the metabolic syndrome

Obesity and the metabolic syndrome have both reached pandemic proportions. Together they have the potential to impact on the incidence and severity of cardiovascular pathologies, with grave implications for worldwide health care systems. The metabolic syndrome is characterized by visceral obesity, insulin resistance, hypertension, chronic inflammation, and thrombotic disorders contributing to endothelial dysfunction and, subsequently, to accelerated atherosclerosis. Obesity is a key component in development of the metabolic syndrome and it is becoming increasingly clear that a central factor in this is the production by adipose cells of bioactive substances that directly influence insulin sensitivity and vascular injury. In this paper, we review advances in the understanding of biologically active molecules collectively referred to as "adipokines" and how dysregulated production of these factors in obese states mediates the pathogenesis of obesity associated metabolic syndrome.

Exfoliated endometrial cell clusters in cervical cytologic preparations are derived from endometrial stroma and glands

Exfoliated endometrial cells are a common finding on Papanicolaou smears obtained during the menstrual period. They have a characteristic morphologic appearance, but whether they are of endometrial glandular, stromal, or mixed origin is still debated. Cervical ThinPrep (Cytyc, Marlboro, MA) slides obtained during menses from women younger than 40 years were immunostained for a stromal (CD10) and an epithelial (keratin proteins) marker. Endometrial cell clusters were scored as purely stromal (composed entirely of CD10+ cells), purely glandular (entirely keratin+ cells), or mixed stromal and glandular. Of the 59 endometrial cell clusters scored, 22 (37%) were purely stromal, 17 (29%) purely glandular, and 20 (34%) mixed stromal and glandular. Exfoliated endometrial cell clusters often are composed exclusively of stromal cells. Mixed stromal-glandular groups and entirely glandular groups also are common. The distinction between stromal and glandular cells is not always possible by conventional Papanicolaou staining but can be established by immunocytochemical study.

Tumeurs endocrines : biologie et physiopathologie

Endocrine tumors are defined as neoplastic lesions resulting from the proliferation of cells engaged in an endocrine differentiation pathway, as shown by their expression of a set of specific markers, including true endocrine markers (such as chromogranine A) and neuro-endocrine markers, shared between neurons and endocrine cells (such as synaptophysin). The demonstration of the synthesis and secretion of one or several hormones is not necessary for the assessment of the endocrine nature of a tumor; only tumors associated with a clinical syndrome resulting from hormone overproduction can be said functioning endocrine tumors. Beyond their common features, endocrine tumors are characterized by a marked diversity, which results from the large functional, structural and embryological heterogeneity of normal endocrine cells. The natural history of endocrine tumors is also characterized by a marked heterogeneity in their evolution and rate of progression. While most endocrine tumors are locally and slowly evolving, some of them behave as truly malignant tumors, as shown by their capacity of metastatic dissemination and their fatal evolution. A better understanding of the cellular and molecular mechanisms involved in tumor progression and metastatic dissemination is necessary for the identification of new prognostic tools and novel therapeutic targets.

Ovarian size and blood flow in women with polycystic ovary syndrome and their correlations with endocrine parameters

OBJECTIVE

To determine how common polycystic ovarian morphology may be in women given the clinical diagnosis of polycystic ovary syndrome (PCOS) based on chronic anovulation and hyperandrogenism and whether certain hormonal factors correlate with ovarian morphology and blood flow.

DESIGN

Prospective study.

SETTING

Two academic endocrinology centers in Italy.

PATIENT(S)

Three hundred twenty-six women with PCOS and 50 age-matched and weight-matched ovulatory women.

INTERVENTION(S)

Ultrasound assessment of ovarian morphology in patients and controls and ovarian blood flow and fasting hormone levels in a subset of 50 patients and matched controls.

MAIN OUTCOME MEASURE(S)

Ovarian morphological assessments, ovarian blood flow by pulsatility index (PI) and resistance index (RI), and measurements of gonadotropins, estrogen, sex hormone-binding globulin, androgens, inhibin B, glucose, and insulin.

RESULT(S)

Using strict ultrasound criteria, 195 woman (60%) had enlarged ovaries, 135 (35%) had normal ovarian size but characteristic morphology, and 16 (5%) had normal size and morphology. Ovarian blood flow was increased (reduced PI and RI) in PCOS. All hormonal parameters were elevated in PCOS. Ovarian size correlated only with insulin and a measure of insulin resistance. Ovarian blood flow correlated positively with insulin, T, free T, and E2 but not with luteinizing hormone. Inhibin B showed a negative correlation with ovarian blood flow.

CONCLUSION(S)

When a clinical diagnosis of PCOS was made, virtually all women were found to have characteristic ovarian morphology. Insulin correlated with increased ovarian size as well as with increased blood flow. Blood flow also correlated positively with sex steroids but negatively with inhibin B.

Coexistence of gastric- and intestinal-type endocrine cells in gastric and intestinal mixed intestinal metaplasia of the human stomach

Intestinal metaplasia (IM) in the human stomach has previously been classified into a gastric and intestinal mixed (GI-IM) and a solely intestinal phenotype (I-IM). The phenotypes of mucous and endocrine cells were evaluated in 3034 glandular ducts associated with chronic gastritis. In the pyloric region, the relative expression of gastric endocrine cell markers, such as gastrin and somatostatin, decreased gradually from glandular ducts with only gastric mucous cell phenotype (G type) to GI-IM toward I-IM, while that of the intestinal endocrine cell markers, glicentin, gastric inhibitory polypeptide (GIP), and glucagon-like peptide-1 (GLP-1) was inversely correlated. In the fundic region, gastrin-positive cells emerged in the pseudo-pyloric and GI-IM glands, whereas I-IM glands did not possess any gastrin-positive cells, suggesting the presence of a distinct pathway of intestinalization. Double staining revealed coexistence of gastrin- and GLP-1-positive cells in the same gland and occasionally in the same cell in GI-IM glands. These results suggest that the phenotypes of endocrine cells are in line with those for mucous counterparts and support the concept that all of the different types of mucous and endocrine cells in normal and IM glands might be derived from a single progenitor cell in each gland.

Small fish models for identifying and assessing the effects of endocrine-disrupting chemicals

Endocrine-disrupting chemicals (EDCs), particularly those that affect the hypothalamic-pituitary-gonadal (HPG) axis of vertebrates, have become a focus of regulatory screening and testing throughout the world. Small fish species, principally the fathead minnow (Pimephales promelas), Japanese medaka (Oryzias latipes), and zebrafish (Danio rerio), are used as model organisms for several of these testing programs. Fish are appropriate models for testing EDCs, not only from the perspective of existing ecological impacts, but also in terms of species extrapolation. Specifically, there is a significant degree of conservation of basic aspects of the HPG axis across vertebrates, which provides a technically robust basis for using results from fish tests to predict likely modes/mechanisms of action of potential EDCs in other vertebrates. Different experimental designs/endpoints for partial- and full-life cycle tests with fish that enable a consideration of a broad range of EDCs are described. Examples of results with specific chemicals in tests with the fathead minnow, medaka, and zebrafish are presented and discussed in terms of sensitivity and specificity for different classes of EDCs.

Laboratory animal science issues in the design and conduct of studies with endocrine-active compounds

The use of rodent models for research and testing on endocrine-active compounds necessitates an awareness of a number of laboratory animal science issues to standardize bioassay methods and facilitate reproducibility of results between laboratories. These issues are not unique to endocrine research but are particularly important in this field due to the complexities and interdependencies of the endocrine system, coupled with the inherently sensitive and variable nature of physiological endpoints. Standardization of animal models and the control of animal environments depend on the establishment of strong scientific partnerships between research investigators and laboratory animal scientists. Laboratory animal care and use programs are becoming increasingly complex and are constantly changing, fueled in part by technological advances, changes in regulations concerning animal care and use, and economic pressures. Since the early 1980s, many institutions have moved to centralization of animal facility operations concomitant with numerous changes in housing systems, barrier concepts, equipment, and engineering controls of the macro- and microenvironment. These and other changes can have an impact on animals and the conduct of endocrine experiments. Despite the potential impact of animal care and use procedures on research endpoints, many investigators are surprisingly naive to the animal facility conditions that can affect in vivo studies. Several key animal care and use issues that are important to consider in endocrine experiments with rodent models are described.

Factors considered in using birds for evaluating endocrine-disrupting chemicals

Documented effects on fish and wildlife populations, coupled with evidence from human poisonings, epidemiology, and experimental toxicology, led to the formation of the Endocrine Disruptor Screening Program within the US Environmental Protection Agency. The main objectives of the program are to validate and implement the screens and tests that have been proposed for evaluating possible endocrine-disrupting activity of chemicals. An avian two-generation test is one of the recommended higher tier tests currently undergoing prevalidation. The advantages and disadvantages of the two species of quail considered as candidates, the northern bobwhite (Colinus virginianus) and the Japanese quail (Coturnix japonica), are described as well as the basis for final selection of the Japanese quail. Among the numerous considerations necessary for ultimately optimizing a two-generation test method using birds, the following key factors are discussed: the number of birds used in the test, when to begin exposure of the P generation, selection and exposure of the F1 generation, and endpoints.

In vitro models in endocrine disruptor screening

The public and scientific concern that chemicals present in the human diet and the environment and their ability to disrupt the normal hormonal milieu in humans and wildlife have become a high-profile international issue. In 1998, the Endocrine Disruptor Screening and Testing Advisory Committee (EDSTAC) convened by the Environmental Protection Agency (EPA) recommended a tiered testing approach for the evaluation of estrogen, androgen, and thyroid-related effects of some 87,000 commercial chemicals and environmental contaminants. The function of this committee concluded with its final report, and the further implementation of the recommended testing strategy has now been carried forward with the assistance of the Endocrine Disruptor Methods Validation Subcommittee. The function of this body is to provide advice to the EPA on scientific and technical issues related specifically to the conduct of studies required for the validation of assays proposed by the EDSTAC as part of the tiered screening program. The EDSTAC recommended and alternative screening batteries encompass four in vitro mammalian assays. The current methodologies and validation status of the proposed in vitro EDSTAC assays are discussed and consist of estrogen/androgen receptor binding, estrogen/androgen gene transactivation, and minced testis, and one alternate (placental aromatase) in vitro screening assay.

Selecting the appropriate rodent diet for endocrine disruptor research and testing studies

Selecting the optimum diet for endocrine disruptor (ED) research and testing studies in rodents is critical because the diet may determine the sensitivity to detect or properly evaluate an ED compound. Dietary estrogens can profoundly influence many molecular and cellular event actions on estrogen receptors and estrogen-sensitive genes. The source, concentration, relative potency, and significance of dietary estrogens in rodent diets are reviewed, including dietary factors that focus specifically on total metabolizable energy and phytoestrogen content, which potentially affect ED studies in rodents. Research efforts to determine dietary factors in commercially available rodent diets that affect uterotrophic assays and the time of vaginal opening in immature CD-1 mice are summarized. A checklist is provided of important factors to consider when selecting diets for ED research and testing studies in rodents. Specific metabolizable energy levels are recommended for particular bioassays. Discussions include the between-batch variation in content of the phytoestrogens daidzein and genistein, the effects of total metabolizable energy and phytoestrogens on the timing (i.e., acceleration) of vaginal opening, and increased uterine weight in immature CD-1 mice. It is concluded that rodent diets differ significantly in estrogenic activity primarily due to the large variations in phytoestrogen content; therefore animal diets used in all ED studies should ideally be free of endocrine-modulating compounds.

Behavioral effects of endocrine-disrupting substances: phytoestrogens

A major source of endocrine-disrupting substances, usually not considered in laboratory animal experiments, is the diet used in research investigations. Soy represents the main protein source in almost all natural-ingredient commercially available formulated diets. Soy-derived isoflavones are the most abundant and in many ways the most studied phytoestrogens, and phytoestrogens (isoflavones) are known endocrine disruptors. Research is reviewed that identifies the physiological and behavioral endocrine-disrupting effects of dietary phytoestrogens (isoflavones) in animal diets, including most of the isoflavones, which are in a glycoside form and biologically inactive, and those in the gastrointestinal tract, which are biologically active. The isoflavones genistein and daidzein have similar molecular weights and structural characteristics to that of 17-beta estradiol, which may enable them to exert estrogenic and antiestrogenic properties are described and characterized. Daidzein can be further metabolized to the potent and abundant molecule equol, which in rodents is produced in very large amounts and represents the major circulating metabolite among all biologically active isoflavones. Equol has the unique and important ability to specifically bind 5 alpha-dihydro-testosterone, and to act in turn to inhibit the action of this potent androgen. The specific influence of dietary soy phytoestrogens on consumptive, learning and memory, and anxiety-related behaviors is identified. Regulatory behaviors such as food and water intake, adipose deposition and leptin, and insulin levels affected by dietary isoflavones are also discussed.

[Cellular functional changes in the endocrine system of the rats upon exposure to coal rock dust and during exercise]

Exposure to coal rock dust in combination with exercise for 2 months was found to have a negative impact on cellular metabolism in the endocrine system. The early form of anthracosilicosis developed in this period. Cytomorphological study revealed cellular changes in the pituitary, thyroid, parathyroid, and pancreatic glands. The cells of the endocrine organs are functionally tense upon exposure to toxic and physical factors and they are most vulnerable in this period of an experiment.

Early-stage carcinoids of the gastrointestinal tract: an analysis of 1914 reported cases

BACKGROUND

Gastrointestinal (GI) carcinoids, considered to be endocrine neoplasms with relatively low levels of malignancy, have never been examined in large, statistically reliable series to determine their true aggressive behavior in the early stage of both minute (</= 5 mm) or small (5.1-10.0 mm) tumors at a depth of invasion restricted to the mucosa and submucosa (sm carcinoids).

METHODS

Of a total number of 1914 cases of GI sm carcinoids selected from the Niigata Registry, 1614 with the tumor size recorded on a millimeter scale were categorized in 5-mm size intervals and rates of metastases were calculated for those in each size category. Of statistical significance was confirmation that the rectum (n = 849), the stomach (n = 449), the duodenum (n = 349), and the jejunoileum (n = 149) were among the principal growth sites. The Kaplan-Meier method was used to calculate 5-year-survival rates (5YSRs) and a comparative study was undertaken.

RESULTS

GI sm carcinoids exhibited a metastasis rate of 16.4% (264 of 1614) as a whole and minute carcinoids (</= 5 mm) revealed an unexpectedly high metastasis rate of 6.0% (24 of 399) on average, which ranged from 3.7% (8 of 216) in the rectum to 17.2% (5 of 29) in the jejunoileum. Small carcinoids measuring 5.1-10 mm also showed a high metastasis rate of 13.3% (90 of 675) on average, ranging from 9.6% (12 of 125) in the stomach to 41.2% (14 of 34) in the jejunoileum. The combined average metastasis rate for both minute and small carcinoids combined (</= 10 mm) was as high as 10.6% (114 of 1074). The comparative study confirmed that, in both the stomach and the rectum, the metastasis rate of sm carcinoids was significantly higher than that for ordinary sm carcinomas in tumors > 10 mm. Although most patients (92.8%; 1777 of 1914) underwent an endoscopy and/or a wider resection of the lesions, nonresectable metastases were found in 22 patients (1.1%). Of these, 16 had undergone a laparotomy and 6 had not received surgery. Among 1001 patients with GI sm carcinoids, the 5YSRs after curative resection ranged from 98.3% in the rectum to 89.6% in the stomach (P < 0.05), representing an average of 96.7% for the entire series.

CONCLUSIONS

Unexpectedly high aggressiveness in metastasis rates in both rectal and gastric sm carcinoids > 10 mm exhibiting values significantly higher than those of sm carcinomas were found in 1914 patients suffering from GI sm carcinoids. However, in sm carcinoids at either the minute or small tumor stage (tumors </= 10 mm), the metastasis rates were comparable to those of sm carcinomas. It should be emphasized that the 5YSRs for patients with GI sm carcinoids may be comparable to those with sm carcinomas in certain cases. These points should be taken into consideration when treating patients with GI carcinoids, particularly in the early stage, and even with the depth of invasion confined to the submucosa.

Metastatic mammary carcinomas with endocrine features: Potential diagnostic pitfalls

Mammary carcinomas with endocrine differentiation (MCED) are an uncommon subtype of breast carcinomas that are morphologically indistinguishable from low-grade endocrine neoplasms arising in other organs. Aspirates of MCED yield relatively monotonous cells with eccentrically placed nuclei containing characteristic "salt and pepper" chromatin. In the breast, these features represent MCED. In extramammary sites, the differential is more extensive, and diagnosing MCED metastases to the lung, a common location for primary and metastatic endocrine tumors, can be a challenging task, with significant clinical implications. Although primary MCED have been described extensively in the cytology literature, secondary pulmonary MCED have not been reported to the best of our knowledge. We report three cases of MCED metastatic to the lung and present the cytological and immunohistochemical features.

Comparative toxicological pathology in mammals and fish: some examples with endocrine disrupters

Toxicologic pathology is a classical discipline in the toxicology arena, and despite various emerging techniques, still is a major cornerstone in the process of hazard identification and risk characterization. Most knowledge derives from laboratory animal studies and, to a lesser extent, human data. Currently interest is growing in applying toxicological pathology for lower animals, in particular fish as being the most developed aquatic genus. This is triggered by the interest in so-called endocrine disrupting chemicals (endocrine disrupters, EDCs), xenobiotics that interfere with the endocrine system and thus may affect reproduction and/or development, and for which pathology is an essential technique in general in vivo studies. As the aquatic ecosystem is a major recipient of pollutants, fish constitute an important potential target and can be used as a research and bio-monitoring tool. For this goal knowledge of the pathological responses of fish to EDCs is essential and therefore we have studied the responses of laboratory fish to a set of reference endocrine modulating chemicals. In this paper, such effects are compared with known response patterns in mammals, thereby accounting for the specific aspects of anatomy and physiology in fish.

Coordinated regression of adrenocortical endocrine and endothelial compartments under adrenocorticotropin deprivation

The adrenal cortex is a complex tissue comprising different cell types, including endocrine, stromal, nerve, perivascular, and endothelial cells. The pituitary hormone ACTH controls the coordinated development of the vasculature and the endocrine tissue mass. This suggests that paracrine secretions between steroidogenic cells and capillary endothelial cells participate in the control of adrenocortical homeostasis. In this paper, we present data demonstrating that ACTH deprivation-induced adrenal atrophy results from alterations of both endocrine and endothelial compartments. These data support the concept that, in addition to its protective effect on endocrine cells, ACTH controls adult adrenal cortex trophicity through an additional paracrine mechanism implying maintenance of the vasculature by VEGF.

Angiogenesis and tumor proliferation/metastasis of human colorectal cancer cell line SW620 transfected with endocrine glands-derived-vascular endothelial growth factor, as a new angiogenic factor

Endocrine glands-derived-vascular endothelial growth factor (EG-VEGF) was recently cloned as a new angiogenic factor that selectively acts on the endothelium of endocrine gland cells. We evaluated the involvement of EG-VEGF in colorectal cancer. The expression of EG-VEGF was confirmed in all of the colorectal cancer cell lines. (On the other hand, the expression of EG-VEGF mRNA was not detected in colorectal normal mucosae.) Stable EG-VEGF infectors of colorectal cancer cell line SW620 were produced, EG-VEGF transfectants were implanted into cecum and s.c., and cell proliferation was evaluated. Angiogenesis was evaluated by dorsal air sac method. Liver metastasis was evaluated after the implantation of EG-VEGF transfectants into the mouse spleen. Tumor proliferation (cecum, s.c.) was significantly higher in the EG-VEGF transfectants than in the control cells. The small vessels were significantly increased in EG-VEGF transfectants as compared with those in control cells. Also, liver metastatic ratio was higher in the EG-VEGF transfectants than in the control cells. In this study, EG-VEGF, a new angiogenic factor, may lead to angiogenesis, promoting cell proliferation and liver metastasis in colorectal cancers. When the EG-VEGF gene-overexpressing colorectal cancer cell line that had been treated with phosphorothioate antisense EG-VEGF oligonucleotides was injected s.c. into mice, angiogenesis and tumor growth were inhibited. Although the novel angiogenesis factor EG-VEGF was not expressed in the normal colorectal mucosa, it was expressed in colorectal cancer cells, which indicates that it is a cancer-specific and possibly tissue-specific angiogenesis factor in the large intestine, and which suggests that it can be targeted by a novel antiangiogenesis therapy.

Selecting Appropriate Animal Models and Experimental Designs for Endocrine Disruptor Research and Testing Studies

Evidence that chemicals in the environment may cause developmental and reproductive abnormalities in fish and wildlife by disrupting normal endocrine functions has increased concern about potential adverse human health effects from such chemicals. US laws have now been enacted that require the US Environmental Protection Agency (EPA) to develop and validate a screening program to identify chemicals in food and water with potential endocrine-disrupting activity. EPA subsequently proposed an Endocrine Disruptor Screening Program that uses in vitro and in vivo test systems to identify chemicals that may adversely affect humans and ecologically important animal species. However, the endocrine system can be readily modulated by many experimental factors, including diet and the genetic background of the selected animal strain or stock. It is therefore desirable to minimize or avoid factors that cause or contribute to experimental variation in endocrine disruptor research and testing studies. Standard laboratory animal diets contain high and variable levels of phytoestrogens, which can modulate physiologic and behavioral responses similar to both endogenous estrogen as well as exogenous estrogenic chemicals. Other studies have determined that some commonly used outbred mice and rats are less responsive to estrogenic substances than certain inbred mouse and rat strains for various estrogen-sensitive endpoints. It is therefore critical to select appropriate biological models and diets for endocrine disruptor studies that provide optimal sensitivity and specificity to accomplish the research or testing objectives. An introduction is provided to 11 other papers in this issue that review these and other important laboratory animal experimental design considerations in greater detail, and that review laboratory animal and in vitro models currently being used or evaluated for endocrine disruptor research and testing. Selection of appropriate animal models and experimental design parameters for endocrine disruptor research and testing will minimize confounding experimental variables, increase the likelihood of replicable experimental results, and contribute to more reliable and relevant test systems.

Estrogen Receptor Knockout Mice as a Model for Endocrine Research

The biological effects of estrogen in mammalian target tissues are important for multiple organ systems including the male and female reproductive tract and the neuroendocrine, skeletal, and cardiovascular systems. Numerous physiological effects of estradiol are modulated by the estrogen receptor (ER), a Class I member of the nuclear receptor superfamily. However, more recent studies have also implicated nongenomic effects of estrogen, which may involve a membrane-binding site. The two forms of the ER are the classical estrogen receptor-alpha (ERalpha) and the more recently discovered estrogen receptor-beta (ERbeta). Gene-targeting techniques were used to generate mice lacking either functional ERalpha (alphaERKO), ERbeta (betaERKO), or both ERs (alphabetaERKO) to provide a model for evaluating estrogen receptor action. These knockout models provide a unique tool to study the effects of estrogen in the context of the whole animal and to discern the role of each ER in various tissues. The reproductive phenotypes as well as some of the nonreproductive phenotypes of the different ERKO models are summarized.