Mechanism of action of the sex steroid hormones (first of three parts)

The male-to-female ratio in late-onset multiple acyl-CoA dehydrogenase deficiency: a systematic review and meta-analysis

BACKGROUND

Late-onset multiple acyl-CoA dehydrogenase deficiency (MADD) is the most common lipid storage myopathy. There are sex differences in fat metabolism and it is not known whether late-onset MADD affects men and women equally.

METHODS

In this systematic review and meta-analysis, the PubMed, Embase, Web of Science, CNKI, CBM, and Wanfang databases were searched until 01/08/2023. Studies reporting sex distribution in patients with late-onset MADD were included. Two authors independently screened studies for eligibility, extracted data, and assessed risk of bias. Pre-specified outcomes of interest were the male-to-female ratio (MFR) of patients with late-onset MADD, the differences of clinical characteristics between the sexes, and factors influencing the MFR.

RESULTS

Of 3379 identified studies, 34 met inclusion criteria, yielding a total of 609 late-onset MADD patients. The overall pooled percentage of males was 58% (95% CI, 54-63%) with low heterogeneity across studies (I2 = 2.99%; P = 0.42). The mean onset ages, diagnostic delay, serum creatine kinase (CK), and allelic frequencies of 3 hotspot variants in ETFDH gene were similar between male and female patients (P > 0.05). Meta-regressions revealed that ethnic group was associated with the MFR in late-onset MADD, and subgroup meta-analyses demonstrated that East-Asian patients had a higher percentage of male, lower CK, and higher proportion of hotspot variants in ETFDH gene than non-East-Asian patients (P < 0.05).

CONCLUSIONS

Male patients with late-onset MADD were more common than female patients. Ethnicity was proved to be a factor influencing the MFR in late-onset MADD. These findings suggest that male sex may be a risk factor for the disease.

Hemoglobin is associated with BMDs and risk of the 10-year probability of fractures in patients with type 2 diabetes mellitus

Purpose

This study aimed to investigate the associations between hemoglobin (HGB) levels and bone mineral density (BMD) and fracture risk in type 2 diabetes mellitus(T2DM) population of different ages.

Method

This cross-sectional study included 641 patients with T2DM (57.9% males). BMD of the femoral neck (FN), total hip (TH), and lumbar spine (LS) were measured using dual-energy X-ray absorptiometry. The 10-year probability of fracture was assessed using a fracture risk assessment tool (FRAX). HGB and other biochemical indices were measured in a certified laboratory at our hospital. Statistical analysis was performed using SPSS 26.0 and R language (R version 4.1.0). Generalized additive models (GAMs) were used to identify the associations between HGB and BMD and fracture risk.

Results

Patients with osteoporosis have lower HGB levels than the non-osteoporotic population and lower FN BMD in patients with anemia than in the non-anemic population. In patients with T2DM, there was sex- and age-related variability in the correlation between HGB levels and BMDs and fracture risk. In older men, HGB level was an independent determinant of BMD and was positively correlated with FN and TH BMD. In non-older women, HGB level was an independent determinant of BMD and fracture risk, positively associated with BMDs and negatively associated with 10-year probability of fracture risk. GAMs revealed a positive linear association between HGB level and BMDs in non-older female patients but not in older male patients.

Conclusion

Our study provides a new perspective on the association of HGB level and BMDs with fracture risk. Relatively high HGB levels are a protective factor for bone quality in patients with T2DM. However, the bone-protective effect of HGB is influenced by age and sex and persists only in older men and non-older women with T2DM.

Steroid hormone signaling: multifaceted support of testicular function

Embryonic development and adult physiology are dependent on the action of steroid hormones. In particular, the reproductive system is reliant on hormonal signaling to promote gonadal function and to ensure fertility. Here we will describe hormone receptor functions and their impacts on testicular function, focusing on a specific group of essential hormones: androgens, estrogens, progesterone, cortisol, and aldosterone. In addition to focusing on hormone receptor function and localization within the testis, we will highlight the effects of altered receptor signaling, including the consequences of reduced and excess signaling activity. These hormones act through various cellular pathways and receptor types, emphasizing the need for a multifaceted research approach to understand their critical roles in testicular function. Hormones exhibit intricate interactions with each other, as evidenced, for example, by the antagonistic effects of progesterone on mineralocorticoid receptors and cortisol's impact on androgens. In light of research findings in the field demonstrating an intricate interplay between hormones, a systems biology approach is crucial for a nuanced understanding of this complex hormonal network. This review can serve as a resource for further investigation into hormonal support of male reproductive health.

Long-Term Exposure to Supraphysiological Levels of Testosterone Impacts Rat Submandibular Gland Proteome

The salivary glands play a central role in the secretion of saliva, whose composition and volume affect oral and overall health. A lesser-explored dimension encompasses the possible changes in salivary gland proteomes in response to fluctuations in sex hormone levels. This study aimed to examine the effects of chronic exposure to testosterone on salivary gland remodeling, particularly focusing on proteomic adaptations. Therefore, male Wistar rats were implanted with subcutaneous testosterone-releasing devices at 14 weeks of age. Their submandibular glands were histologically and molecularly analyzed 47 weeks later. The results underscored a significant increase in gland mass after testosterone exposure, further supported by histologic evidence of granular duct enlargement. Despite increased circulating sex hormones, there was no detectable shift in the tissue levels of estrogen alpha and androgen receptors. GeLC-MS/MS and subsequent bioinformatics identified 308 proteins in the submandibular glands, 12 of which were modulated by testosterone. Of note was the pronounced upregulation of Klk3 and the downregulation of Klk6 and Klk7 after testosterone exposure. Protein-protein interaction analysis with the androgen receptor suggests that Klk3 is a potential target of androgenic signaling, paralleling previous findings in the prostate. This exploratory analysis sheds light on the response of salivary glands to testosterone exposure, providing proteome-level insights into the associated weight and histological changes.

The effect of sex steroid hormones on the ecology of in vitro oral biofilms

Sex steroid hormones (SSH) such as oestrogen, progesterone and testosterone are cholesterol derived molecules that regulate various physiological processes. They are present in both blood and saliva, where they come in contact with oral tissues and oral microorganisms. Several studies have confirmed the effect of these hormones on different periodontal-disease-associated bacteria, using single-species models. Bacteria can metabolize SSH, use them as alternative for vitamin K and also use them to induce the expression of virulence factors. However, it is still unclear what the effects of SSH are on the oral microbiome. In this study, we investigated the effects of four SSH on commensal in vitro oral biofilms. Saliva-derived oral biofilms were grown in Mc Bain medium without serum or menadione using the Amsterdam Active-Attachment model. After initial attachment in absence of SSH, the biofilms were grown in medium containing either oestradiol, oestriol, progesterone or testosterone at a 100-fold physiological concentration. Menadione or ethanol were included as positive control and negative control, respectively. After 12 days with daily medium refreshments, biofilm formation, biofilm red fluorescence and microbial composition were determined. The supernatants were tested for proteolytic activity using the Fluorescence Resonance Energy Transfer Analysis (FRET). No significant differences were found in biofilm formation, red fluorescence or microbial composition in any of the tested groups. Samples grown in presence of progesterone and oestradiol showed proteolytic activity comparable to biofilms supplemented with menadione. In contrast, testosterone and oestriol showed a decreased proteolytic activity compared to biofilms grown in presence of menadione. None of the tested SSH had large effects on the ecology of in vitro oral biofilms, therefore a direct translation of our results into in vivo effects is not possible. Future experiments should include other host factors such as oral tissues, immune cells and combinations of SSH as present in saliva, in order to have a more accurate picture of the phenomena taking place in both males and females.

Male Reproduction and Aging

Recent publications of well-conducted population studies have informed us that the syndromic prevalence of age-related low testosterone, also known as late-onset hypogonadism, is quite low. Several well-conducted trials in middle-aged and older men with age-related decline in testosterone levels have revealed that efficacy of testosterone therapy is modest with improvement in sexual function, mood, volumetric bone density, and anemia. Although select older men might benefit from testosterone therapy, its effect on prostate cancer risk and major adverse cardiovascular events remains unclear. The results of the ongoing TRAVERSE trial will likely provide important insights into these risks.

The associations between uric acid with BMDs and risk of the 10-year probability of fractures in Chinese patients with T2DM stratified by age and gender

PURPOSE

Accumulating evidence suggests that serum uric acid (SUA) plays a beneficial role in bone health in the general population through antioxidant mechanisms. However, there is controversy over the association between SUA and bone in patients with type 2 diabetes mellitus (T2DM). We aimed to investigate the association of serum UA with BMDs and future fracture risks and its potential influencing factors in those patients.

METHOD

This was a cross-sectional study of 485 patients. BMDs at femoral neck (FN), Troch and the lumbar spine (LS) were measured by DXA. The 10-year probability of fracture risk was assessed using the fracture risk assessment tool (FRAX). SUA level and other biochemical indexes were measured.

RESULTS

There were lower SUA concentrations in patients with osteoporosis/osteopenia compared with those in the normal group, which only existed in non-elderly men and elderly women with T2DM. After adjustment for potential confounders, SUA was positively associated with BMD and negatively with 10-year probability of fracture risk only in non-elderly men and elderly women with T2DM. Multiple stepwise regression analysis showed that SUA was an independent determinant of BMD and 10-year probability of fracture risk, which also occurred in the above patients.

CONCLUSION

These results implied that relatively high SUA is a protective factor for bone in T2DM patients, but the osteoprotective effect of SUA was mediated by age and gender, and persisted only in non-elderly men and elderly women. Large intervention studies are needed to further confirm the outcomes and provide possible explanations.

Androgen Metabolism and Response in Prostate Cancer Anti-Androgen Therapy Resistance

All aspects of prostate cancer evolution are closely related to androgen levels and the status of the androgen receptor (AR). Almost all treatments target androgen metabolism pathways and AR, from castration-sensitive prostate cancer (CSPC) to castration-resistant prostate cancer (CRPC). Alterations in androgen metabolism and its response are one of the main reasons for prostate cancer drug resistance. In this review, we will introduce androgen metabolism, including how the androgen was synthesized, consumed, and responded to in healthy people and prostate cancer patients, and discuss how these alterations in androgen metabolism contribute to the resistance to anti-androgen therapy.

Sex Steroid Hormones as a Balancing Factor in Oral Host Microbiome Interactions

Sex steroid hormones (SSH) are cholesterol-derived molecules. They are secreted into saliva and enter the oral cavity, triggering physiological responses from oral tissues, with possible clinical implications, such as gingival inflammation and bleeding. SSH and hormonal changes affect not only oral host cells but also oral microorganisms.

Historically, most research has focused on the effect of hormonal changes on specific bacteria and yeasts. Recently a broader effect of SSH on oral microorganisms was suggested. In order to assess the role of SSH in host-microbe interactions in the oral cavity, this review focuses on how and up to what extent SSH can influence the composition and behavior of the oral microbiome. The available literature was reviewed and a comprehensive hypothesis about the role of SSH in host-microbiome interactions is presented. The limited research available indicates that SSH may influence the balance between the host and its microbes in the oral cavity.

Mechanisms for Sex Differences in Energy Homeostasis

Sex differences exist in the regulation of energy homeostasis. Better understanding of the underlying mechanisms for sexual dimorphism in energy balance may facilitate development of gender-specific therapies for human diseases, e.g. obesity. Multiple organs, including the brain, liver, fat and muscle, play important roles in the regulations of feeding behavior, energy expenditure and physical activity, which therefore contribute to the maintenance of energy balance. It has been increasingly appreciated that this multi-organ system is under different regulations in male vs. female animals. Much of effort has been focused on roles of sex hormones (including androgens, estrogens and progesterone) and sex chromosomes in this sex-specific regulation of energy balance. Emerging evidence also indicates that other factors (not sex hormones/receptors and not encoded by the sex chromosomes) exist to regulate energy homeostasis differentially in males vs. females. In this review, we summarize factors and signals that have been shown to regulate energy homeostasis in a sexually dimorphic fashion and propose a framework where these factors and signals may be integrated to mediate sex differences in energy homeostasis.

Hormonal Influences on Cognitive Function

This article examines how hormonal changes may affect the neuronal networking and mechanisms of cognitive function. Hormones are the chemical regulators of the human body and function critically to maintain various processes, such as growth, emotions and even cognition. Numerous studies have examined the relationship between hormonal effects and cognitive function; these studies have investigated different factors, such as aging, pregnancy, post-natal states, emotions and stress. Different types of hormones produce different outcomes for the human body and mind. Hormones may also contribute to both positive and negative outcomes, depending on whether the hormone levels are too low or too high. To investigate the hormonal effects on cognitive function, the sources of localisation must be localised, so that the neuronal network can be realised. Furthermore, cognitive function does not rely on a specific brain region but is determined by the neuronal network interactions. Thus, it is worthwhile to know the neural mechanisms behind cognitive functions that are affected by hormones.

Testosterone Levels and Type 2 Diabetes-No Correlation with Age, Differential Predictive Value in Men and Women

Most studies reporting on the association of circulating testosterone levels with type 2 diabetes in men are of cross-sectional design. Reports on the relevance of altered testosterone levels in women are scarce. Here, we evaluate the role of low serum testosterone levels for incident diabetes in men and women in a population setting of 7706 subjects (3896 females). During a mean follow up time of 13.8 years, 7.8% developed type 2 diabetes. Significant correlations of testosterone with high density lipoprotein (HDL)-cholesterol (R = 0.21, p < 0.001), body-mass-index (R = −0.23, p < 0.001), and waist-to-hip-ratio (R = −0.21, p < 0.001) were found in men. No correlation was found with age in men; in women, the correlation was negligible (R = 0.04, p = 0.012). In men, low testosterone levels predicted high risk of type 2 diabetes, while in women this relationship was opposite. Men with low testosterone levels showed increased risk of future diabetes (hazard ratio (HR) 2.66, 95% confidence interval (CI) 1.91–3.72, p < 0.001 in basic model; HR 1.56 95%, CI 1.10–2.21, p = 0.003). In women, low testosterone levels indicated lower risk with (HR 0.53, 95% CI 0.37–0.77, p = 0.003), while the association lost significance in the fully adjusted model (HR 0.72, 95% CI 0.49–1.05, p = 0.09). Low levels of testosterone predicted future diabetes in men. A borderline opposite association was found in women.

Low testosterone levels are predictive for incident atrial fibrillation and ischaemic stroke in men, but protective in women - results from the FINRISK study

Background Atrial fibrillation is the most common serious abnormal heart rhythm, and a frequent cause of ischaemic stroke. Recent experimental studies, mainly in orchiectomised rats, report a relationship between sex hormones and atrial electrophysiology and electroanatomy. We aimed to evaluate whether low testosterone levels are predictive for atrial fibrillation and/or ischaemic stroke in men and women. Design and methods The serum total testosterone levels were measured at baseline in a population cohort of 7892 subjects (3876 male, 4016 female), aged 25-74 years, using a commercially available immunoassay. The main outcome measure was atrial fibrillation or ischaemic stroke, whichever came first. Results During a median follow-up of 13.8 years, a total of 629 subjects (8.0%) suffered from incident atrial fibrillation ( n = 426) and/or ischemic stroke ( n = 276). Cox regression analyses, adjusted for age (used as time-scale), geographical region, total cholesterol (log), high-density lipoprotein-cholesterol (log), hypertension medication, known diabetes, smoking status, waist-hip-ratio, and time of blood drawn, documented differential predictive value of low sex-specific testosterone levels for atrial fibrillation and/or ischaemic stroke, in men and in women: Increasing levels were associated with lower risk in men (hazard ratio per one nmol/l increase 0.98 (95% confidence interval 0.93-1.00); p = 0.049). On the other hand, increasing testosterone levels were associated with higher risk in women (hazard ratio per one nmol/l increase 1.17 (95% confidence interval 1.02-1.36); p = 0.031). Conclusion Our study indicates that low testosterone levels are associated with increased risk of future atrial fibrillation and/or ischaemic stroke in men, while they are protective in women.

Estrogen Receptors and Post-Receptor Markers in Human Breast Cancer: A Reappraisal

Several major defects in the estrogen receptor pathway have been evidenced in most human breast cancers by an immunofluorescence tracing of estradiol receptor complexes at the single cell level. Endogenous peroxidase seems a reliable postreceptor marker for estrogen-sensitive breast cancer cells. Since almost all human breast cancers appear to include both hormone-sensitive and autonomous cell populations, a combined use of endocrine and cytotoxic regimens is urged. The hormonal regulation of tumor growth parameters could be exploited in order to achieve a maximum recruitment of synchronized tumor cells at risk to chemotherapy.

Reproductive aging in men

Aging in men is associated with a decrease in serum testosterone levels due to attrition in testicular Leydig cells and slowing of the hypothalamic GnRH pulse generator. The practicing endocrinologist is frequently consulted for consideration of testosterone therapy in older men with late-onset hypogonadism (LOH), a condition that many clinicians fail to distinguish from organic hypogonadism. Recent data using syndromic definition show that only 2% of 40-80-year-old men have LOH. Co-morbidities and obesity strongly contribute to LOH, suggesting that testosterone is a biomarker of health. Hence, prevention and treatment of these co-morbidities might attenuate age-related decline in androgen levels.

History, biology, and health inequities: emergent embodied phenotypes and the illustrative case of the breast cancer estrogen receptor

How we think about biology--in historical, ecological, and societal context--matters for framing causes of and solutions to health inequities. Drawing on new insights from ecological evolutionary developmental biology and ecosocial theory, I question dominant gene-centric and ultimately static approaches to conceptualizing biology, using the example of the breast cancer estrogen receptor (ER). Analyzed in terms of its 4 histories--societal, individual (life course), tumor (cellular pathology), and evolutionary--the ER is revealed as a flexible characteristic of cells, tumors, individuals, and populations, with magnitudes of health inequities tellingly changing over time. This example suggests our science will likely be better served by conceptualizing disease and its biomarkers, along with changing magnitudes of health inequities, as embodied history--that is, emergent embodied phenotype, not innate biology.

Novel estrogen target gene ZAS3 is overexpressed in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a prototypic, inflammatory autoimmune disease characterized by significant gender bias. Previous studies have established a role for hormones in SLE pathogenesis, including the sex hormone estrogen. Estrogen regulates gene expression by translocating estrogen receptors (ER) α and β into the nucleus where they induce transcription by binding to estrogen response elements (EREs) of target genes. The ZAS3 locus encodes a signaling and transcriptional molecule involved in regulating inflammatory responses. We show that ZAS3 is significantly up-regulated in SLE patients at both the protein and mRNA levels in peripheral blood mononuclear cells (PBMCs). Furthermore, estrogen stimulates the expression of ZAS3 in vitro in several leukocyte and breast cancer cell lines of both human and murine origin. In vivo estrogen treatment mediates induction of tissue specific ZAS3 expression in several lymphoid organs in mice. Estrogen stimulation also significantly up-regulates ZAS3 expression in primary PBMCs, while treatment with testosterone has no effect. Mechanistically, estrogen induces differential ERα binding to putative EREs within the ZAS3 gene and ERα knockdown with siRNA prevents estrogen induced ZAS3 up-regulation. In contrast, siRNA targeting IFNα has no effect. These data demonstrate that ZAS3 expression is directly regulated by estrogen and that ZAS3 is overexpressed in lupus. Since ZAS3 has been shown to regulate inflammatory pathways, its up-regulation by estrogen could play a critical role in female-biased autoimmune disorders.

The CXCL12/CXCR4 axis promotes ligand-independent activation of the androgen receptor

The molecular mechanisms responsible for the transition of some prostate cancers from androgen ligand-dependent to androgen ligand-independent are incompletely established. Molecules that are ligands for G protein coupled receptors (GPCRs) have been implicated in ligand-independent androgen receptor (AR) activation. The purpose of this study was to examine whether CXCL12, the ligand for the GPCR, CXCR4, might mediate prostate cancer cell proliferation through AR-dependent mechanisms involving functional transactivation of the AR in the absence of androgen. The results of these studies showed that activation of the CXCL12/CXCR4 axis promoted: The nuclear accumulation of both wild-type and mutant AR in several prostate epithelial cell lines; AR-dependent proliferative responses; nuclear accumulation of the AR co-regulator SRC-1 protein; SRC-1:AR protein:protein association; co-localization of AR and SRC-1 on the promoters of AR-regulated genes; AR- and SRC-1 dependent transcription of AR-regulated genes; AR-dependent secretion of the AR-regulated PSA protein; P13K-dependent phosphorylation of AR; MAPK-dependent phosphorylation of SRC-1, and both MAPK- and P13K-dependent secretion of the PSA protein, in the absence of androgen. Taken together, these studies identify CXCL12 as a novel, non-steroidal growth factor that promotes the growth of prostate epithelial cells through AR-dependent mechanisms in the absence of steroid hormones. These findings support the development of novel therapeutics targeting the CXCL12/CXCR4 axis as an ancillary to those targeting the androgen/AR axis to effectively treat castration resistant/recurrent prostate tumors.

Cellular expression and localization of estrogen receptor α and progesterone receptor mRNA in the bovine oviduct combining laser-assisted microdissection, quantitative PCR, and in situ hybridization

The importance of using techniques that allow the study of pure populations of cells has been increasingly recognized. The authors used laser-assisted microdissection (LAM) in combination with quantitative real-time PCR (qPCR) to assess the relative expression of mRNAs encoding estrogen receptor α (ERα) and progesterone receptor (PR) in the different compartments of the bovine oviduct (epithelium, stroma, smooth muscle coat) during the follicular and mid-luteal phases of the estrus cycle. The localization of receptor mRNA was further studied using non-radioactive in situ hybridization (NISH). A special focus was on whether formalin fixation and paraffin embedding influence the quality and quantity of mRNA obtained from microdissected material. Distinct cyclic changes of the mRNA in the bovine oviduct were observed with elevated levels of PR mRNA transcripts in the epithelium and smooth muscle coat during the follicular phase. The expression of PR mRNA did not vary significantly in the stroma of the bovine oviduct during follicular and mid-luteal phases. In conclusion, the authors found that LAM with qPCR can precisely locate and accurately quantify mRNA expression in specific cell populations from formalin-fixed and paraffin-embedded oviductal tissue.

Developmental programming: prenatal androgen excess disrupts ovarian steroid receptor balance

Steroid hormones play an important role in reproduction and the receptors through which they signal change in a developmental time, follicle stage, and cell-specific manner. Disruption in steroid receptor expression affects follicle formation and differentiation. In this study, using prenatal testosterone (T) and dihydrotestosterone (DHT)-treated female sheep as model systems, we tested the hypothesis that prenatal androgen excess disrupts the developmental ontogeny of ovarian steroid receptor protein expression. Pregnant Suffolk ewes were injected twice weekly with T propionate or DHT propionate (a non-aromatizable androgen) in cottonseed oil from days 30 to 90 of gestation. Changes in ovarian estrogen receptors (ER; ESR1, ESR2), androgen receptor (AR) and progesterone receptor (PGR) proteins were determined at fetal (days 90 and 140), postpubertal (10 months), and adult (21 months; only prenatal T-treated sheep studied) ages by immunohistochemistry. Prenatal T and DHT treatment induced selective increase in AR but not ER or PGR expression in the stroma and granulosa cells of fetal days 90 and 140 ovaries. An increase in ESR1 and decrease in ESR2 immunostaining coupled with increased AR expression were evident in granulosa cells of antral follicles of 10- and 21-month-old prenatal T but not DHT-treated females (analyzed only at 10 months). These findings provide evidence that an early increase in ovarian AR is the first step in the altered ovarian developmental trajectory of prenatal T-treated females, and manifestations of postnatal ovarian dysfunction are likely facilitated via altered equilibrium of antral follicular granulosa cell ER/AR protein expression.

Effects of prostaglandin E2 and progesterone on rat brain synaptosomal plasma membranes

The lipid fluidity of rat brain synaptosomal plasma membranes (SPM) labelled with 1,6-diphenyl-1,3,5-hexatriene (DPH) was increased by prostaglandin E2 (PGE2) and decreased by progesterone, as indicated by steady-state fluorescence anisotropy [(ro/r)-1]-1. Arrhenius-type plots of [(ro/r)-1]-1 indicated a lipid phase separation of SPM at approximately 23.5 degrees C which was reduced to approximately 18.1 degrees C by PGE2 and increased to approximately 34.6 degrees C by progesterone. Treatment of SPM by PGE2 and progesterone caused an increase of the lipid phase separation to approximately 32.4 degrees C. Arrhenius plots of Na+/K(+)-ATPase activity in control SPM exhibited a break point at approximately 23.1 degrees C which was reduced to approximately 17.8 degrees C by PGE2 and increased to approximately 32.6 degrees C by progesterone. SPM treated with PGE2 plus progesterone showed an increased break point at approximately 29.3 degrees C. Na+/K(+)-ATPase activity was increased at a PGE2 concentration range between 0.1 and 3 microM; higher concentrations (up to 10 microM) led to a gradual inhibition of enzyme activity. Progesterone (0.1-10 microM) and PGE2 plus progesterone both produced a gradual decrease in enzyme activity. The allosteric inhibition of Na+/K(+)-ATPase by fluoride (F-) (as reflected by changes in the Hill coefficient) was modulated by PGE2 and progesterone. The perturbations of membrane lipid structure and changes in membrane fluidity provide a basis for suggesting an independent non-genomic mechanism for the progesterone-induced alterations in the effects of PGE2 on brain function.

Predicting pharmacophore signals for post-coital antifertility activity of 1-trifluoromethyl-1,2,2-triphenylethylene derivatives: a statistical approximation using E-state index

Considering the worth of developing non-steroidal estrogen analogues, the present research explores the pharmacophores of 1-trifluoromethyl-1,2,2-triphenylethylenes (Fig. 1) for post-coital antifertility activity using electrotopological state atom (E-state) index. The study shows the efficacy of E-state index in developing statistically acceptable model, which explains the electronic environment and topological states of different atoms in a molecule. The exploration concluded that phenyl ring attached to an ethylenic moiety, para substitution by nucleophilic group on the phenyl ring and presence of strong electronegative group as the 4th substituent on the 1st carbon of the ethylenic moiety might be crucial for activity.

The influence of cyclosporine A therapy on sex hormone levels in pre- and post-menopausal women with primary biliary cirrhosis

The mechanism underlying sex hormone disturbances in post-menopausal women with primary biliary cirrhosis is unclear, but these alterations may occur as a consequence of liver disease. As cyclosporine may have some therapeutic potential is this condition, we have evaluated short-term alterations in plasma sex hormone levels in 11 pre- and 19 post-menopausal women with primary biliary cirrhosis following randomisation to cyclosporine A or placebo therapy. Baseline sex hormone binding globulin levels were markedly depressed in all pre-menopausal women but were elevated for the post-menopausal group when compared to standard reference ranges. Testosterone and dihydrotestosterone levels were low or markedly depressed in both patient groups. Androstendione concentrations tended to be higher than the normal range in the post-menopausal group. Oestradiol levels were within the normal range for the pre-menopausal group but were relatively higher in the post-menopausal group than in other normal post-menopausal women. Cyclosporine A therapy resulted in significant decreases in sex hormone binding globulin levels (26.6 +/- 5.0 to 16.2 +/- 4.6 nmol/l; p < 0.05) in the premenopausal group and reduction in total (336 +/- 163 to 140 +/- 132 pmol/l; p < 0.01) and free (6 +/- 5 to 2 +/- 3 pmol/l; p < 0.05) oestradiol levels in the post-menopausal group at 6 months. There were no significant alterations in other hormonal parameters. No temporal changes occurred in the placebo group. Cyclosporine A therefore induces significant but variable sex hormone changes in both pre- and post-menopausal women with primary biliary cirrhosis.

Evidence for receptors specific for 17 beta-estradiol and testosterone in chondrocyte cultures

Recently, sex hormones were shown to stimulate chondrocyte differentiation and matrix protein synthesis in vitro in a sex-specific and maturation-dependent manner. The aim of the present study was to determine whether cytosolic receptors in these cells would specifically bind 17 beta-estradiol and testosterone, and if so, whether binding was gender- and maturation-dependent. Confluent, fourth passage cultures of cells derived from male or female rat costochondral growth zone and resting zone cartilage were homogenized and specific binding of 17 beta-estradiol or testosterone measured in the cytosolic fraction. Scatchard analysis indicated the presence of a high-affinity 17 beta-estradiol receptor (Kd = 4.5 to 8.7 x 10(-11) M), with low binding capacity (3.9 to 11.2 fmol/mg protein). Chondrocytes from female rats were found to have a significantly greater binding capacity for 17 beta-estradiol than chondrocytes from male rats. However, cells from both sexes had binding capacities that were independent of cell maturation. A high-affinity testosterone receptor (Kd = 4.3 to 6.3 x 10(-11) M) with low binding capacity (4.1 to 5.9 fmol/mg protein) was found in both males and females, but no difference in binding capacity was noted, either as a function of gender or stage of cell maturation. Immunohistochemistry using antibodies against 17 beta-estradiol and testosterone and the 17 beta-estradiol nuclear receptor (D-75) confirmed that 17 beta-estradiol and testosterone receptors were present in chondrocytes from both male and female rats. These data demonstrate that chondrocytes from growth zone and resting zone cartilage are capable of binding both 17 beta-estradiol and testosterone. This suggests that these hormones mediate their direct effects on chondrocytes via receptors specific for their appropriate ligand. The sex-specific effects of 17 beta-estradiol may be due to differences in receptor number between chondrocytes derived from female and male rats. In contrast, the sex-specific effects of testosterone may be regulated at the post receptor level since no differences in binding capacity were found between males and females.

Messenger RNA phenotyping for semi-quantitative comparison of glucocorticoid receptor transcript levels in the developing embryonic mouse palate

A specific complex of glucocorticoid and receptor interacts with responsive genes in target tissues of developing palate and controls its morphogenesis. In order to examine developmental changes in glucocorticoid receptor gene expression during embryonic palate formation, variations in transcript levels have been determined using a simple semi-quantitative reverse transcription-polymerase chain reaction (PCR) procedure. Oligo (dT)16 was used as the primer for reverse transcription, and the amount of PCR product for glucocorticoid receptor was normalized against those for glyceraldehyde 3-phosphate dehydrogenase (GAPDH) and beta-actin. We found that either GAPDH or beta-actin were suitable internal standards, and that the mRNA levels of glucocorticoid receptor undergoes a significant decrease of 30% at the developmental stage of embryonic mouse palatal shelf re-orientation. Immunolocalization of the receptor demonstrated a significant change in the distribution pattern of glucocorticoid receptor during the re-orientation stage of secondary palate formation. Our present data suggest that developmental variations in glucocorticoid receptor level control morphogenetic events of secondary palate formation.

CDRI-85/287, a novel antiestrogen and antiimplantation agent: biological profile and interaction with the estrogen receptors in immature rat uterus

Postcoital antifertility efficacy, estrogenic and antiestrogenic activities of compound 85/287 were determined by the subcutaneous route in rats. It was 100% effective in preventing implantation at 0.5 mg/kg dose when administered within 24 h of mating and at 0.05 mg/kg in the days 1-5 post-coitum regimen. In the immature rat bioassay, it exhibited mild uterotrophic effect at the contraceptive dose but when administered along with estradiol (E2), it caused almost complete inhibition of uterine weight gain and vaginal cornification at the 2 mg/kg dose. E2 administration to immature rats (0.1 microgram, s.c., 3 days) caused 3-5 fold increase in the nuclear as well as cytoplasmic estradiol receptor (ER) content as compared to controls. In contrast, 85/287 (0.5 mg/kg and 2 mg/kg; s.c.), only translocated the ER to the nuclear compartment resulting in a depletion of cytoplasmic ER levels. Concurrent administration of 85/287 and E2 inhibited E2-induced increase in cytoplasmic ER. It is suggested that compound 85/287 exerts its antiestrogenic and antiimplantation action by interfering with the formation of E2-receptor complexes in the uterus.

Inhibition of the 17 beta-estradiol-induced and constitutive expression of the cellular protooncogene c-fos by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in the female rat uterus

Acute administration of 17 beta-estradiol (5 micrograms/rat) to 25-day-old female Sprague-Dawley rats resulted in an increase of uterine mRNA for the cellular oncogene c-fos. The c-fos mRNA levels were significantly elevated 12 and 24 h after exposure to the hormone (232 and 164% of control values) and the elevation was not observed after 48 h. In contrast, treatment of the animals with either 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) or 6-methyl-1,3,8-trichlorodibenzofuran (MCDF) resulted in a dose-dependent decrease in constitutive uterine c-fos mRNA levels. In rats co-treated with 17 beta-estradiol plus TCDD or MCDF, it was apparent from the results that the halogenated aromatic hydrocarbons significantly inhibited the estrogen-induced increases in uterine c-fos mRNA levels. These observations further extend the diverse spectrum of antiestrogenic effects caused by TCDD and related compounds and also show an interaction between TCDD and the constitutive expression of the c-fos proto-oncogene in the female rat uterus.

Studies on the mechanism of action of oral contraceptives with regard to fibrinolytic variables

Evidence is provided that the fibrinolytic capacity in plasma is strongly dependent on circulating concentrations of tissue plasminogen activator rather than on concentrations of plasminogen activator inhibitor. Thus a decrease in plasma tissue plasminogen activator concentrations, as is the case in oral contraceptive users, may result in a decrease in plasma fibrinolytic capacity despite a parallel decrease in plasminogen activator inhibitor levels. It is now clear that the presence of specific intracellular receptors and a given motif in the genome are essential to mediate hormone-dependent regulation of gene expression. A computer search revealed potential estrogen and glucocorticoid-progesterone-responsive elements in the genes coding for tissue plasminogen activator, plasminogen activator inhibitor, and some other fibrinolytic variables. No convincing evidence for the presence of sex steroid receptors in endothelial cells was found, but liver cells clearly contain estrogen and androgen receptors. However, neither endothelial cells nor hepatocytes cultured in vitro showed a change in tissue plasminogen activator or plasminogen activator inhibitor synthesis on incubation with sex steroids (10(-9) to 10(-6) mol/L) for 3 days. An alternative explanation for the observed decreases in tissue plasminogen activator and plasminogen activator inhibitor concentrations in the plasma of oral contraceptive users is discussed.

Modulation of steroid production in goat ovarian cells: effect of progestins and antiprogestins

Effect of various synthetic progestins and antiprogestational compounds on progesterone (P) and estradiol (E) production by isolated goat ovarian granulosa (G) and corpus luteum (CL) cell types was studied in vitro. Steroid production was studied either under basal conditions or after stimulation with follicle stimulating hormone (FSH) in the presence of aromatase substrate, androstenedione (A). None of the progestins had any significant effect on basal P and E production by either cell types during 48 hour of culture. The FSH and A - induced increase in P and E production was significantly inhibited following concommitant treatment with synthetic progestins at concentrations higher than 10(-7) M. The added progestins had no effect on G and CL cell viability. None of the antiprogestational compounds had any significant effect on basal steroid production in either of the cell types. Furthermore, the higher concentrations of three antiprogestins namely RMI 14156, STS 557 and isomer 201 of RMI 12936, were found to stimulate significantly the basal as well as FSH + A - induced production of estradiol in both the cell types. In contrast, the other two antiprogestins tested were found to stimulate the gonadotropin + A - induced production of P. These results indicate that exogeneous progestins directly inhibit the gonadotropin + androstenedione - induced steroid production by G and CL cells in vitro. Moreover, different antiprogestin had different effect on the modulation of steroid production.

Functional estrogen receptors as biochemical marker for the detection of hormone-dependent breast cancer

The translocatable receptors categorized as functional receptors were quantitated in a cross-incubation study of breast cancer nuclei with receptor-rich uterine cytosol. Data demonstrated that tumors that contained cytosolic estrogen receptor (ER) but had translocation defect might not be hormone dependent, whereas tumors with low ER but intact nuclear translocation step will respond to antiestrogen therapy. Cytosolic ER was estimated in 114 primary breast cancer tissues and ten metastatic axillary lymph nodes; 58% of postmenopausal and 54% of premenopausal breast cancer tissues were ER+ with a cutoff value of 10 fmoles and 3 fmoles/mg protein, respectively. Of tumors in the premenopausal and postmenopausal state, 62% and 57%, respectively, were positive for nuclear ER, with a cutoff value of 10 fmoles/100 micrograms DNA. This study suggested that evaluation of functional ER level would reduce the number of false-negative and false-positive tumors.

Characterization of high affinity and low affinity dexamethasone binding sites on male rat liver nuclear envelopes

Steroids must traverse the nuclear envelope before exerting their action at the chromatin. However, few studies have been done to elucidate the mechanism by which steroids traverse this membrane barrier. As first steps towards investigating the mechanism, we have characterized the binding sites for dexamethasone on male rat liver nuclear envelopes. The nuclear envelopes, prepared in the presence of dithiothreitol, were isolated from purified nuclei after treatment with DNase 1 at high pH. Binding of dexamethasone to the nuclear envelopes was measured after 16 h of incubation at 0-4 degrees C. At pH 7.4, only a single high capacity, low affinity binding site for dexamethasone was identified. However, at pH 8.6, two sites were identified; a low capacity, high affinity site and a high capacity, low affinity site. Adrenalectomy of the animal before preparation of the membranes caused loss of the high affinity site and reduction in the number of the lower affinity sites. Acute dexamethasone treatment of adrenalectomized rats resulted in the reappearance of the high affinity site but long term treatment with dexamethasone was required for complete restoration of the high affinity sites and reappearance of any of the low affinity sites. The steroid specificity of these nuclear envelope binding sites was different from that of the cytosolic glucocorticoid receptor, generally showing broader specificity. However, triamcinolone acetonide, which is a potent competitor for binding to the glucocorticoid receptor, did not complete effectively. The binding sites were sensitive to protease treatment and salt extraction studies revealed that the dexamethasone binding sites do not represent proteins non-specifically bound to the nuclear envelope. The affinity and the hormone responsiveness of the high affinity site are similar to those of the nuclear glucocorticoid receptor. Therefore, the nuclear envelope may be a site of action of glucocorticoids.

Biochemical effects of 17 beta-estradiol on UMR106 cells

The effect of 17 beta-estradiol (E) on an osteoblast-like cell line, UMR106, was studied in vitro. The concentrations of transferrin and seven enzymes (gamma glutamyl transferase, alkaline phosphatase, acid phosphatase, lactate dehydrogenase, creatine kinase, alanine aminotransferase and aspartate aminotransferase) were measured in these cells after incubation in culture medium containing either E or the vehicle. E treatment increased five of the seven enzymes and increased the transferrin concentration in the UMR106 cells while simultaneously reducing the proliferation rates. 4-Hydroxytamoxifen, an estrogen antagonist, produced a mild estrogen agonist action on growth rates and enzyme concentrations in the UMR106 cells. When E was present simultaneously, the agonist properties of 4-hydroxytamoxifen were enhanced. These studies show that E enhanced activity of five enzymes and the transferrin content of UMR106 cells after a 2-day incubation. 4-Hydroxytamoxifen enhanced the E effect, illustrating that estrogen antagonists may manifest agonist or antagonist properties depending on the model. These results extend our previous observations showing a direct effect of E in vitro on osteoblast-like cells.

Mechanisms that lead to disease of the endocrine system in animals

Endocrine glands are collections of specialized cells that synthesize, store, and release their secretions directly into the blood stream. They are sensing and signalling devices located in the extracellular fluid compartment and are capable of responding to changes in the internal and external environments to coordinate a multiplicity of activities that maintain homeostasis. Diseases of the endocrine system are encountered in many animal species and present challenging diagnostic problems. The major pathogenic mechanisms responsible for disturbances in endocrine function include: 1) primary hyperfunction of an endocrine gland; 2) secondary hyperfunction; 3) primary hypofunction of an endocrine gland; 4) secondary hypofunction; 5) endocrine hyperactivity secondary to diseases of other organs; 6) hypersecretion by nonendocrine tumors of hormone-like substances; 7) failure of fetal endocrine function; 8) endocrine dysfunction due to failure of target cell response; 9) endocrine dysfunction resulting from abnormal degradation of hormone; and 10) iatrogenic syndromes of hormone-excess. For each major category, several specific disease problems have been selected to illustrate the morphologic and functional changes that characterize the response of a particular endocrine gland to disruption of function.

Androgen receptors in colorectal adenomas

To evaluate the potential effect of androgens on the development and growth of human colorectal adenomas, the prevalence and concentration of cytosolic androgen receptors (AR) were analysed in 26 adenomas and 19 samples of normal colonic mucosa by a hybrid ligand receptor-binding assay. AR were detected in 7 of the adenomas (26.9%), and in 6 of the normal mucosa samples (31.6%). In the adenomas, AR levels demonstrated were low, ranging from 6 to 31 fmol/mg cytosol protein, and dissociation constants (Kds) ranged from 0.17-2.7 X 10(-9) M. Of 13 adenomas excised from men, 6 (46%) had positive receptor activity, whereas only 1 of 13 (7.7%) from women was positive (P = 0.03, Fisher's exact test). There was no correlation between AR titre and patient age, or between adenoma size and histological type or degree of dysplasia. In normal mucosa, AR levels ranged from 7 to 33 fmol/mg and Kds ranges from 0.24-3.1 X 10(-9) M. There was no significant difference between either AR prevalence or levels in the adenomas and normal mucosa. The sex difference was exclusive to the adenoma. Endogenous androgen may play a role in adenoma development early in the promotional process.

Hypogonadism in liver cirrhosis: implication in altered amino acid metabolism in muscle

To investigate the relationship between hypogonadism and altered amino acid metabolism in patients with liver cirrhosis, we measured the basal levels of plasma testosterone, estradiol, and free amino acids, plus urinary 3-methylhistidine excretion, in 16 control and 19 cirrhotic patients. The concentration of plasma testosterone correlated significantly with that of plasma branched-chain amino acids, and inversely with urinary 3-methylhistidine excretion. This suggests that hypogonadism causes a disturbance in amino acid metabolism at least partly related to an augmented muscle protein turnover.

Effects of sex steroid hormones on differentiation of adipose precursor cells in primary culture

The effects of estradiol-17 beta and progesterone on multiplication, differentiation and lipid filling of adipose precursor cells were examined in primary cell cultures of cells prepared from adipose tissue of both male and ovariectomized female rats. Progesterone down to a concentration of 10(-7) mol/liter, alone or in the presence of estradiol-17 beta stimulated the development of glycerophosphate dehydrogenase and lipoprotein lipase activity. Estradiol-17 beta alone had no effects. These effects were essentially parallel to increases in the rate of lipid filling of the cells. Furthermore, the formation of cells with a lipid vacuole greater than 20 micron was markedly stimulated, suggesting that new fat cells were formed by the stimulation of differentiation of the adipose precursor cells. No effects of the sex steroid hormones were seen on the rate of multiplication. These results suggest a role of sex steroid hormones in the regulation of triglyceride storage capacity in adipose tissue by facilitating the differentiation of precursor cells to form new adipocytes.

Induction of monocytic differentiation by calcitriol (1,25-dihydroxyvitamin D3) in the human promyelocytic leukemic cell line (HL-60) in serum-free medium

The effect of calcitriol on the induction of differentiation in human promyelocytic leukemic cell line (HL-60) cultured in serum-free chemically defined medium (SFM) was investigated. The utilization of SFM containing RPMI-1640 basal medium supplemented with insulin (5 micrograms/ml), transferrin (5 micrograms/ml), sodium selenite (5 ng/ml), and bovine serum albumin (0.5 micrograms/ml), transferrin examination of the cellular/molecular mechanism of calcitriol's action in HL-60 cell differentiation without interference of components present in serum. HL-60 cells grown in SFM were induced to differentiate into monocytes/macrophages by calcitriol as indicated by induction of differentiation-associated biological and biochemical parameters: chemiluminescent (CL) responsiveness, lysozyme activity, nonspecific esterase, expression of cell surface antigens, and reduced proliferation. The exposure of HL-60 cells in SFM to calcitriol (from 10(-10) to 10(-8)M) resulted in dose-dependent induction of these parameters, which was similar to those obtained with cells grown in 10% fetal calf serum containing medium (10% SCM). However, calcitriol was 5-fold more potent for HL-60 cells cultured in SFM than those cultured in 10% SCM as indicated by shifts in dose-response curves for induction of CL responsiveness and lysozyme activity. The effect of calcitriol on the proliferation and acquisition of several monocyte-associated cell surface antigens was also more sensitive for HL-60 cells cultured in SFM than for cells grown in 10% SCM. We characterized and quantitated calcitriol receptors in HL-60 cells cultured in SFM in comparison to those in 10% SCM after exposing intact cells to radiolabeled calcitriol. Cells cultured in either SFM or 10% SCM exhibited calcitriol receptors that migrated at 3.4S as a single peak on sucrose gradients and elicited inherent DNA binding ability. There was essentially no difference in the apparent dissociation constants (Kd) nor in the number of calcitriol binding sites per HL-60 cell, that is approximately 6.0 X 10(-11) M and approximately 3000 binding sites/cell respectively. It is concluded that culturing HL-60 cells in SFM results in full expression of calcitriol-induced phenotypic changes excluding the possibility that such changes result from the indirect effect of calcitriol mediated by identified and/or unidentified components present in serum.

An experimental study of vascular damage in estrogen-induced embolization

Temporal sequences of estrogen-induced embolization were studied in both in vivo and in vitro models. Infusion of the estrogen compound into rat mesenteric artery caused local spherocytosis and severe rapid degeneration of endothelial cells, followed by injury to the underlying muscle cells and fibroblasts. These changes were regarded as mainly the results of the embolization effect of conjugated estrogen. A study of cultured vascular endothelial cells suggested narrow margins of effective drug concentrations for cell damage. Also, nuclear disintegration with relative sparing of cytoplasmic constituents seemed to be characteristic of estrogen-induced cell damage in both in vivo and in vitro models.

Estimation of oestrogen and progesterone receptors in chronic rhinitis

The turbinates of 38 patients with chronic rhinitis were examined biochemically for oestrogen and progesterone receptors. Low levels of oestrogen-receptor-like activity (1-20 fmol/mg protein) were found in 50% of patients of both sexes. Progesterone receptor activity was also weak (1-16 fmol/mg protein) but was present only in 5 female patients. Immunocytochemical assay failed to demonstrate focal areas of oestrogen receptor activity. One juvenile nasopharyngeal angiofibroma was negative for both oestrogen and androgen receptors. Other possible mechanisms of hormonal action are considered.

Circumscribed endometrial stromatosis of the uterus with marked epitheliogenesis

A 75-year-old female suffered from continuous abnormal genital bleeding; endometrial biopsy was interpreted as stromal hyperplasia. Simple total abdominal hysterectomy with bilateral salpingo-oophorectomy was performed. A circumscribed tumor covered by atrophic endometrium was found in the uterine fundus, bulging into the endometrial cavity; histological pictures revealed endometrial stromatosis with marked epitheliogenesis having a papillary formation and sex-cord-like differentiation. No recurrence or metastasis was detected postoperatively.