New perspectives on PPAR, VDR and FXRα as new actors in testicular pathophysiology.

The incidence of reproductive disorders is constantly increasing and affects 15% of couples, with male's abnormalities diagnosed in almost half of the cases. The male gonads exert two major functions of the testis with the productions of gametes (exocrine function) and of sexual hormones (endocrine function). In the last decades, next to steroid receptors such as estrogen and androgen receptors, the involvement of other members of the nuclear receptor superfamily have been described such as Steroidogenic factor-1 (SF-1), Nerve growth factor IB (NGFIB), Liver-X-Receptorα (LXRα) and Dosage-sensitive sex reversal, adrenal hypoplasia critical region, on chromosome X, gene 1 (DAX-1). The purpose of this review is to highlight the emerging roles of some members of the nuclear receptor superfamily among which the vitamin-D Receptor (VDR), Peroxisome Proliferator-Activated Receptor (PPAR), Farnesoid-X-Receptor-α (FXRα). We discuss how these receptors could participate to explain male fertility disorders; and their potential to be use as biomarkers or therapeutic targets for management of fertility disorders.

COVID-19 restrictions and recreational fisheries in Ontario, Canada: Preliminary insights from an online angler survey.

The COVID-19 pandemic and corresponding public health mitigation strategies have altered many facets of human life. And yet, little is known about how public health measures have impacted complex socio-ecological systems such as recreational fisheries. Using an online snowball survey, we targeted resident anglers in Ontario, Canada, to obtain preliminary insights on how the pandemic has impacted recreational fishing and related activity. We also explored angler perspectives on pandemic-related restrictions and other aspects of fisheries management. Our results point to the value of recreational fisheries for the mental and physical well-being of participants, as well as the value and popularity of outdoor recreation during a pandemic. Although angling effort and fish consumption appeared to decline during the early phases of the pandemic, approximately 21 % of the anglers who responded to our survey self-identified as new entrants who had begun or resumed fishing in that time. Self-reported motivations to fish during the pandemic suggest that free time, importance to mental and physical health, and desires for self-sufficiency caused some anglers to fish more, whereas a lack of free time, poor or uncertain accessibility, and perceived risks caused some anglers to fish less. Respondents also expressed their desires for more clear and consistent communication about COVID-19 fishing restrictions from governments, and viewed angling as a safe pandemic activity. Information on recreational angler behaviours, motivations, and perspectives during the pandemic may prove valuable to fisheries managers and policy makers looking to optimize their strategies for confronting this and other similar crises.

Performance of predictive tools to identify individuals at risk of non-traumatic fracture: a systematic review, meta-analysis, and meta-regression.

There is no consensus on which tool is the most accurate to assess fracture risk. The results of this systematic review suggest that QFracture, Fracture Risk Assessment Tool (FRAX) with BMD, and Garvan with BMD are the tools with the best discriminative ability. More studies assessing the comparative performance of current tools are needed. INTRODUCTION: Many tools exist to assess fracture risk. This review aims to determine which tools have the best predictive accuracy to identify individuals at high risk of non-traumatic fracture. METHODS: Studies assessing the accuracy of tools for prediction of fracture were searched in MEDLINE, EMBASE, Evidence-Based Medicine Reviews, and Global Health. Studies were eligible if discrimination was assessed in a population independent of the derivation cohort. Meta-analyses and meta-regressions were performed on areas under the ROC curve (AUCs). Gender, mean age, age range, and study quality were used as adjustment variables. RESULTS: We identified 53 validation studies assessing the discriminative ability of 14 tools. Given the small number of studies on some tools, only FRAX, Garvan, and QFracture were compared using meta-regression models. In the unadjusted analyses, QFracture had the best discriminative ability to predict hip fracture (AUC = 0.88). In the adjusted analysis, FRAX with BMD (AUC = 0.81) and Garvan with BMD (AUC = 0.79) had the highest AUCs. For prediction of major osteoporotic fracture, QFracture had the best discriminative ability (AUC = 0.77). For prediction of osteoporotic or any fracture, FRAX with BMD and Garvan with BMD had higher discriminative ability than their versions without BMD (FRAX: AUC = 0.72 vs 0.69, Garvan: AUC = 0.72 vs 0.65). A significant amount of heterogeneity was present in the analyses. CONCLUSIONS: QFracture, FRAX with BMD, and Garvan with BMD have the highest discriminative performance for predicting fracture. Additional studies in which the performance of current tools is assessed in the same individuals may be performed to confirm this conclusion.

Denosumab compared to other treatments to prevent or treat osteoporosis in individuals at risk of fracture: a systematic review and meta-analysis.

UNLABELLED: The aim of this review is to compare the efficacy and safety of denosumab over other treatments for osteoporosis. The results of this study suggest that the safety of denosumab and its efficacy in reducing fractures is not significantly different from bisphosphonates. Denosumab was, however, more effective in increasing bone mineral density. INTRODUCTION: This study was conducted to compare the efficacy and safety of denosumab over other pharmacological treatments for osteoporosis in individuals at risk of fracture. METHODS: Randomised controlled trials comparing denosumab with another pharmacological treatment for osteoporosis were searched in MEDLINE, EMBASE and CENTRAL. Identified articles were screened by two independent reviewers and assessed for inclusion. Data from included studies were extracted and meta-analyses were conducted using random effects models. RESULTS: Nine studies including a total of 4890 postmenopausal women were identified. The follow-up period varied from 12 to 24 months. In all studies except one, the comparator treatment was a bisphosphonate. There was no statistically significant difference between patients receiving denosumab and those receiving a bisphosphonate in terms of fracture risk (RR[95 % CI] = 1.15 [0.84-1.58]), adverse events (RR[95 % CI] = 0.99 [0.96-1.02]) or deaths (OR[95 % CI] = 0.58 [0.12-2.71]). Withdrawals due to adverse events were less frequent in denosumab than in other treatment groups but the difference did not reach statistical significance (OR[95 % CI] = 0.68 [0.45-1.04]). The percent change in bone mineral density at the total hip, lumbar spine, femoral neck and one-third radius was significantly higher in participants who received denosumab (e.g. mean difference [95 % CI] at the total hip: 1.06 [0.86-1.25]). CONCLUSIONS: These results suggest that, after 12 to 24 months, the safety and efficacy of denosumab for reducing fracture risk is not significantly different from bisphosphonates despite higher gains in bone mineral density. In a clinical setting, denosumab may demonstrate greater effectiveness.

The impact of educational interventions on modifiable risk factors for osteoporosis after a fragility fracture.

The purpose of this study was to investigate the impact of two educational interventions on the intake of calcium and vitamin D supplements and modifiable risk factors for osteoporosis in women ≥50 years with a fragility fracture (FF). Within 6-8 months of fracture, women were randomized to one of three intervention groups: usual care (UC), written materials (WM), or videocassette and written materials (VC). The written materials for patients and their physician provided information on osteoporosis, FF, and available treatments; written materials for physician were provided through patients. The videocassette presented similar information as the written material, but in greater depth. Twelve months after randomization, the effectiveness of the interventions was assessed. The study cohort consisted of 1,175 women undiagnosed and untreated for osteoporosis. After 12 months, the mean intake of Ca supplements increased by 33, 93, and 91 mg/day for the UC, WM, and VC groups, respectively (p value, WM vs UC = 0.163; VC vs UC = 0.026); the corresponding mean increases for vitamin D were 58, 105, and 118 IU/day (p value, WM vs UC = 0.214; VC vs UC = 0.012). The proportion of women who increased their Ca and vitamin D intake by supplements was similar in all three groups. The intervention had a greater impact in those not taking supplements at randomization and had no impact on modifiable risk factors. In women without diagnosis and treatment for osteoporosis, the interventions seem effective at increasing the amounts of Ca and vitamin D supplements, but not effective at inciting more women to increase their consumption. Therefore, the clinical significance of the impact of the intervention is difficult to evaluate.

Influence of nucleophosmin/B23 on DNA binding and transcriptional activity of the androgen receptor in prostate cancer cell.

The promotion and progression of prostate cancer (PCa) are associated with androgen receptor (AR) signalling. AR functions are modulated by a variety of co-factors amongst which we identified the nucleophosmin (NPM/B23), a member of the histone chaperone family. Here, we show that NPM is overexpressed in PCa compared to normal adjacent tissues. AR and NPM interact in vitro and in vivo, and NPM is critical for androgen-dependent transcriptional activation in LNCaP cells as an anti-NPM siRNA downregulates transcription of a transfected androgen response element (ARE)-containing reporter promoter as well as expression of the endogenous androgen responsive prostate-specific antigen (PSA) gene. By investigating the effect of NPM on AR, we have also observed that NPM enhances AR binding to an ARE in vitro in electrophoretic gel mobility-shift assay experiments. Chromatin immunoprecipitation studies further demonstrated that both AR and NPM associate with AREs of the PSA gene in vivo. Altogether, our data suggest that the molecular histone chaperone NPM could regulate AR functions by promoting assembly of AR-containing regulatory complexes and that high levels of NPM might alter AR functions in PCa.

The 26S proteasome system degrades the ERM transcription factor and regulates its transcription-enhancing activity.

ERM is a member of the ETS transcription factor family. High levels of the corresponding mRNA are detected in a variety of human breast cancer cell lines, as well as in aggressive human breast tumors. As ERM protein is almost undetectable in these cells, high degradation of this transcription factor has been postulated. Here we have investigated whether ERM degradation might depend on the proteasome pathway. We show that endogenous and ectopically expressed ERM protein is short-lived protein and undergoes proteasome-dependent degradation. Deletion mutagenesis studies indicate that the 61 C-terminal amino acids of ERM are critical for its proteolysis and serve as a degradation signal. Although ERM conjugates with ubiquitin, this post-translational modification does not depend on the C-terminal domain. We have used an Ets-responsive ICAM-1 reporter plasmid to show that the ubiquitin-proteasome pathway can affect transcriptional function of ERM. Thus, ERM is subject to degradation via the 26S proteasome pathway, and this pathway probably plays an important role in regulating ERM transcriptional activity.

Flexibility and running economy in female collegiate track athletes.

AIM: Limited information exists regarding the association between flexibility and running economy in female athletes. This study examined relationships between lower limb and trunk flexibility and running economy in 17 female collegiate track athletes (20.12+/-1.80 y). METHODS: Correlational design, subjects completed 4 testing sessions over a 2-week period. The 1st session assessed maximal oxygen uptake (VO2max=55.39+/-6.96 ml.kg-1.min-1). The 2nd session assessed trunk and lower limb flexibility. Two sets of 6 trunk and lower limb flexibility measures were performed after a 10-min treadmill warm-up at 2.68 m.s-1. The 3rd session consisted of 3 10-min accommodation runs at a speed of 2.68 m.s-1 which was approximately 60% VO2max. Each accommodation bout was separated by a 10-min rest. The 4th session assessed running economy. Subjects completed a 5-min warm-up at 2.68 m.s-1 followed by 10-min economy run at 2.68 m.s-1. RESULTS: Pearson product moment correlations revealed no significant correlations between running economy and flexibility measures. CONCLUSION: Results are in contrast to studies demonstrating an inverse relationship between trunk and/or lower limb flexibility and running economy in males. Furthermore, results are in contrast to studies reporting positive relationships between flexibility and running economy.

Locomotor rehabilitation in a complex virtual environment.

Virtual reality (VR) technology offers a new and safe way to increase practice time and provide the varied environments and constraints needed to optimize locomotor training. Our specific objectives are (1) to create a virtual environment (VE) coupled with a self-paced treadmill for locomotor training; (2) to compare temporal and distance measurements of gait during treadmill walking while looking at different scenarios of VE; and (3) to develop a protocol optimized for the training of locomotor disorders after stroke. A motorized treadmill was mounted on a six-degree-of-freedom motion platform. VEs were created using commercial software (SoftImage) and projected on a large screen, while system control was administered through the CAREN software (Motek BV). The instantaneous treadmill speed and scene progression were servo-controlled. Preliminary results show that healthy subjects are able to have full control of their own walking speed both on the treadmill and within the virtual scene, while experiencing a strong sense of presence. A street crossing training protocol has been developed for locomotor training. It is expected that locomotor training with increasingly complex VEs will allow persons with stroke to increase progressively their locomotor capacity, as required and entrained by the VE.

Geographical variations in the epidemiology of bacterial sexually transmitted infections in Manitoba, Canada.

Feasible epidemiological approaches are required to make a better assessment of the stage of an epidemic and to monitor its transition through various phases. Application of the Lorenz curve and Gini coefficient to summarise the inequality in STD incidence rates between jurisdictions in Manitoba, Canada, was found to provide useful insights into the concentration of these epidemics over time and thus their transition through epidemic phases. Further exploration of the statistical properties of these and other indices of inequality and their potential application to STD epidemiology is warranted. New epidemiological tools are also required for better monitoring of the impact of prevention and control activities and to inform the content of these activities.

Discussion of lifestyle-related issues in family practice during visits with general medical examination as the main reason for encounter: an exploratory study of content and determinants.

The aim of this study was to describe the frequency and content of discussions on lifestyle issues during an annual examination and to identify characteristics of patients, physicians, and visits associated with lifestyle discussions. Audio-recordings of the visits of 35 family physicians with 148 of their patients were analyzed. Bivariate descriptive and multivariate analyses were used. On average, the visits contained discussions of 3.6 different issues for a total time of 2.9 min. Of the 11 topics of interest, weight, diet and nutrition, physical activity, and tobacco use were the most frequently discussed. Consultation with a female physician and perception by the physician of a poorer patient mental health status were associated with the number of themes discussed and the duration of exchanges. Results suggest that although, discussions on lifestyle issues are frequently observed during these visits, they remain limited in scope. Physicians appear to concentrate their energy on targeted patients, and female doctors are more active in this domain.

Medical faculty as humanistic physicians and teachers: the perceptions of students at innovative and traditional medical schools.

BACKGROUND AND OBJECTIVES: The training of caring physicians represents an important goal of medical education. Little is known however, on whether medical faculty constitute good role models for teaching humanistic skills to medical students. In this study, we examined to what extent medical students at innovative and traditional schools perceived their teachers as humanistic physicians and teachers. We also explored whether pre-clinical and clinical students shared the same perceptions. METHODS: A mail survey was conducted in Canada of all second-year students and senior clerks at one innovative medical school (problem-based learning (PBL), patient-centred, community-oriented) and three traditional medical schools. Students were asked to what extent they agreed or disagreed that the majority of their teachers behaved as humanistic physicians and teachers; 10 statements were used. Overall, 65% of the 1039 students returned the questionnaire. RESULTS: Over 25% of second-year students and 40% of senior clerks did not agree that their teachers behaved as humanistic caregivers with patients or were good role models in teaching the doctor-patient relationship. More than half of second-year students and senior clerks did not agree that their teachers valued human contact with them or were supportive of students who had difficulties. There were few differences in the way medical students at innovative and traditional schools perceived their teachers' humanistic qualities. At the pre-clinical level however, there were more students from the innovative school than from the traditional schools (around 60% vs. 40%, P < 0.005) who agreed that their teachers valued human contact with them and were supportive of students. CONCLUSION: Our results indicate that the PBL curriculum fosters better teacher-student relationships during the pre-clinical years. They also suggest that an unacceptably large number of medical students are taught by physicians who seem to lack compassion and caring in their interactions with patients. This study questions the adequacy of medical faculty as role models for the acquisition of caring competence by medical students.

The PEA3 group of ETS-related transcription factors. Role in breast cancer metastasis.

The ets genes encode eukaryotic transcription factors that are involved in tumorigenesis and developmental processes. The signature of the Ets family is the ETS-domain, which binds to sites containing a central 5'-GGAA/T-3' motif. They can be sub-classified primarily because of the high amino acid conservation in their ETS-domains and, in addition, in the conservation of other domains generally characterized as transactivating. This is the case for the PEA3 group, which is currently made up of three members, PEA3/E1AF, ER81/ETV1 and ERM, which are more than 95% identical in the ETS-domain and more than 85% in the transactivation acidic domain. The members of the PEA3 group are activated through both the Ras-dependent and other kinase pathways, a function which emphasizes their involvement in several oncogenic mechanisms. The expression pattern of the three PEA3 group genes during mouse embryogenesis suggests that they are differentially regulated, probably to serve important functions such as tissue interaction. Although the target genes of these transcription factors are multiple, their most frequently studied role concerns their involvement in the metastatic process. In fact, PEA3 group members are over-expressed in metastatic human breast cancer cells and mouse mammary tumors, a feature which suggests a function of these transcription factors in mammary oncogenesis. Moreover, when they are ectopically over-expressed in non-metastatic breast cancer cells, these latter become metastatic with the activation of transcription of matrix metalloproteinases or adhesion molecules, such as ICAM-1.

Characteristics of problem gambling in a Canadian context: a preliminary study using a DSM-IV-based questionnaire.

OBJECTIVE: To develop a self-report instrument to assess diagnostic criteria and associated features of pathological gambling in order to learn more about the characteristics of individuals who seek treatment for gambling problems in a Canadian setting. METHOD: Fifty-seven adults seeking treatment for gambling problems at the Addictions Foundation of Manitoba were assessed. RESULTS: There was substantial variation in the endorsement of Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) symptoms. Lying to family members or friends and "chasing" previous gambling losses were frequently reported, while more serious consequences (for example, relationship breakup, job losses) were less frequent. DSM-IV ratings were correlated (r = 0.59) with the South Oaks Gambling Screen. Many individuals reported gambling as a way to alleviate dysphoric mood, and 30% reported receiving mental health services in the past. Approximately 50% reported suicidal ideation, although recent suicide attempts were not common. CONCLUSION: These preliminary results of Canadian adults seeking treatment for gambling problems suggest a somewhat different profile from many United States studies, which often rely on older male pathological gamblers. More systematic investigation of the presence of major depression and other psychiatric disorders is warranted. Consistent with demographic data collected at the Addictions Foundation of Manitoba, it appears that video lottery terminals play a major role in the type of problem gambling experience seen in Canadian settings.

[Supporting the conjugal system during the perinatal period: an experience in participatory research]. / Soutenir le système conjugal pendant la période périnatale: une expérience de recherche participatoire.

This article presents the process and results of a participatory study intended to develop and evaluate preventive interventions for couples in the process of becoming new parents. A total of 21 participants, 4 physicians, 8 couples, and an investigator, studied the interventions using a research approach derived from a constructivist paradigm, the fourth generation evaluation. Employing a family intervention model, the nurse guided and contributed to the investigation. The results enabled physicians to refine their perinatal care and facilitated the couples' adjustment to the arrival of their first child. The interventions, the research process, and the use of a family nursing model are promising for nursing applications.

Clinical teachers as humanistic caregivers and educators: perceptions of senior clerks and second-year residents.

BACKGROUND: The acquisition and nurturing of humanistic skills and attitudes constitute an important aim of medical education. In order to assess how conducive the physician-learning environment is to the acquisition of these skills, the authors determined the extent to which clinical teachers are perceived by their trainees as humanistic with patients and students, and they explored whether undergraduate and graduate students share the same perceptions. METHODS: A mail survey was conducted in 1994/95 of all senior clerks and second-year residents at Laval University, University of Montreal and University of Sherbrooke medical schools. Of 774 trainees, 259 senior clerks and 238 second-year residents returned the questionnaire, for an overall response rate of 64%. Students' perceptions of their teachers were measured on a 6-point Likert scale applied to statements about teachers' attitudes toward the patient (5 items) and toward the student (5 items). RESULTS: On average, only 46% of the senior clerks agreed that their teachers displayed the humanistic characteristics of interest. They were especially critical of their teachers' apparent lack of sensitivity, with as many as 3 out of 4 declaring that their teachers seemed to be unconcerned about how patients adapt psychologically to their illnesses (75% of clerks) and that their teachers did not try to understand students' difficulties (78%) or to support students who have difficulties (77%). Compared with the clerks, the second-year residents were significantly less critical, those with negative perceptions varying from 27% to 58%, 40% on average. Except for this difference, their pattern of responses from one item to another was similar. INTERPRETATION: This study suggests the existence of a substantial gap between what medical trainees are expected to learn and what they actually experience over the course of their training. Because such a gap could represent a significant barrier to the acquisition of important skills, more and urgent research is needed to understand better the factors influencing students' perceptions.

Modulation of 17alpha-hydroxylase/17,20-lyase activity of guinea pig cytochrome P450c17 by site-directed mutagenesis.

Microsomal cytochrome P450c17 (17a-hydroxylase/17,20-Lyase) catalyzes two reactions in the delta5 and delta4 pathways leading to the production of C19 steroids. Transient expression of human, bovine, porcine, rat, and mouse P450c17 cDNAs showed that the protein has 17alpha-hydroxylase and 17,20-Lyase activities, converting pregnenolone and progesterone into delta5- and delta4-Cl9 steroids, respectively, although the rat and mouse proteins have a preferential pathway toward the delta4 steroids. The guinea pig (gp) P450c17 shares 46% to 70% amino acid identity with the corresponding proteins of other species, and further characterization indicated that the guinea pig enzyme only converts progesterone to androstenedione. In this study, we have tried to identify amino acid(s) in the gpP450c17 that governs such a steroid specificity. Among the various mutants that we have created, change of the arginine (R) residue at position 200 to an asparagine (N) (R200N) in the gpP450c17 protein increased reactivity toward pregnenolone compared with the wild-type enzyme. Pregnenolone was converted into 17alpha-hydroxypregnenolone and dehydroepiandrosterone. However, this gain occurred at the expense of the 17,20-lyase activity toward 17alpha-hydroxyprogesterone. The R200N mutation in the gpP450c17 protein introduced a potential N-linked glycosylation site (200Asn-X-Thr202); however, substitution of the Thr202 residue by an asparagine (R200N/T202N), which abolishes the site, did not change the preference of the gpP450c17 mutant for pregnenolone. Furthermore, introduction of a putative glycosylation site at amino acid 185 in the gpP450c17 enzyme did not alter substrate specificity. The properties of the amino acid were also investigated, and neither the charge nor the size of the sidechain elicited change in the substrate specificity of gpP450c17. Thus, our results demonstrate that the mutation of arginine to asparagine at position 200 changes the substrate specificity of the gpP450c17 enzyme.

Alcohol and morbidity in the Lung Health Study.

OBJECTIVE: There is a well documented J-shaped relationship between alcohol consumption and mortality that is not fully understood. Differences between studies, particularly in the use of cigarette smoking as a covariate, may partially explain inconsistencies in findings. This study sought to clarify the nature of this alcohol-smoking-mortality relationship. METHOD: The Lung Health Study enrolled 5,887 (3,702 male; 95% white) cigarette smokers with airways obstruction, aged 35 to 60. Measures of smoking, drinking and body mass index were available annually over the 5-year duration of the study, and pattern of alcohol use and diastolic blood pressure were assessed at baseline. Heavy drinkers were excluded from the sample. Documented evidence of hospitalizations was used in establishing morbidity. Proportional hazards regression was used for analysis. RESULTS: A significant protective effect of moderate drinking was found among men, but not women. There was also no apparent interaction between smoking status and drinks per week (both time dependent) in these data on morbidity and mortality. A baseline pattern of drinking eight or more drinks per occasion, but less than once a month, among men was associated with fewer hospitalizations and deaths. CONCLUSIONS: This study confirmed the general relationships between use of alcohol and illness or death, but with a few unexpected results. Further investigation is needed to identify whether these unexpected findings were due to our somewhat unique sample, to our use of hospitalization as the primary outcome measure, or to other causes.

Regulation of cytochrome P450 cholesterol side-chain cleavage, 3 beta-hydroxysteroid dehydrogenase/delta 5-delta 4 isomerase type 1 and estradiol-17 beta-hydroxysteroid dehydrogenase mRNA levels by calcium in human choriocarcinoma JEG-3 cells.

In human placenta the cytochrome P450 side-chain cleavage (P450scc) and 3 beta-hydroxysteroid dehydrogenase type 1 (3 beta-HSD-1) convert cholesterol and pregnenolone producing progesterone, whereas 17 beta-hydroxysteroid dehydrogenase type 1 (17 beta-HSD-1) mediates the interconversion of estrone and estradiol. We have examined the effects of calcium on phorbol ester- and cAMP-induced P450scc, 3 beta-HSD-1 and 17 beta-HSD-1 mRNAs in human JEG-3 cells. A23187 increased in a dose-dependent fashion in the 1.3 kb 17 beta-HSD-1 mRNA whereas a weaker increase followed by a gradual depletion effect of A23187 was observed on 3 beta-HSD-1 mRNA. No significant effect of A23187 on P450scc mRNA was observed. Using 0.50 microM of A23187 the induction of 3 beta-HSD-1 and 17 beta-HSD-1 mRNAs was maximum within about 6 h whereas P450scc mRNA levels stayed unaffected throughout the time-course period. The action of A23187 was synergistic on cAMP-stimulated 17 beta-HSD-1 mRNA levels, while in a dose-dependent manner A23187 progressively depleted 3 beta-HSD-1 and P450scc mRNA abundance probably by activation of a calcium-/calmodulin-dependent phosphodiesterase. On the phorbol 12-myristate, 13-acetate (PMA)-stimulated 3 beta-HSD-1, 17beta-HSD-1 and P450scc mRNA levels only the lowest concentration of A23187 potentialized the PMA effect on the 17 beta-HSD-1 mRNA levels. Using thapsigargin (TG), a cell-permeable sesquiterpene lactone that releases calcium by inhibiting sarco/endoplasmic reticular calcium-ATPase, our data indicated the presence in JEG-3 cells of TG-sensitive and TG-insensitive calcium-ATPases regulating 3 beta-HSD-1 and 17 beta-HSD-1 mRNA levels. These results emphasized the complexity of calcium contribution with the protein kinase A and C pathways in the regulation of P450scc, 3 beta-HSD-1 and 17 beta-HSD-1 mRNA levels. In addition, the different sensitivity of these genes to calcium suggest they could be activated by different subclasses of PKCs.

Expression of the genes for 3 beta-hydroxysteroid dehydrogenase type 1 and cytochrome P450scc during syncytium formation by human placental cytotrophoblast cells in culture and the regulation by progesterone and estradiol.

We have investigated the expression of cholesterol side-chain cleavage cytochrome P450 (P450scc) and 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD) type 1 genes during human trophoblast differentiation in culture and the modulation of their steady-state mRNA levels by steroids. During the first 24 to 48 h after plating, mononucleated cells aggregated, forming colonies. After 60 h in culture, cell diameters were increased and nuclei appeared centrally distributed within large cells, consistent with syncytiotrophoblast formation. During these striking morphological changes in culture the expression and activity levels of 3 beta-HSD type 1 and P450scc increased significantly as isolated cytotrophoblasts progressed to a differentiated state, with P450scc and 3 beta-HSD type 1 mRNAs activities being more abundant in cells cultured for 48 to 72 h. In the same culture, however, the amount of 3 beta-HSD protein decreased during the first 12 to 24 h by 50% compared with freshly isolated trophoblasts but remained at these levels throughout the culture period. The specific activity of the 3 beta-HSD as determined with pregnenolone or dehydroepiandrosterone was similar but increased with time as syncytiotrophoblast was formed in vitro. These observations provide additional evidence that the expression of these two progesterone-synthesizing enzymes is coincident and that they reach their maximum steady-state mRNA levels at a time when syncytium formation occurs in vitro. Incubation of trophoblast cells with progesterone or estradiol increased the abundance of P450scc and 3 beta-HSD type 1 mRNAs but had no significant effect on the amount of 3 beta-HSD protein. These observations of the regulation of 3 beta-HSD type 1 mRNA levels by steroids suggest a complex relationship of the mechanisms regulating transcription/mRNA processing and transduction of the 3 beta-HSD type 1 gene.