Human sperm decondensation in vitro is related to cleavage rate and embryo quality in IVF.

PURPOSE: To investigate whether the ability of human spermatozoa to decondense in vitro in the presence of heparin (Hep) and glutathione (GSH) is related to assisted reproduction (ART) success. METHODS: Cross-sectional pilot study involving male partners of 129 infertile couples undergoing ICSI with (45) or without (84) donor oocytes at two infertility clinics in CABA, Argentina, between October 2012 and December 2013. In vitro decondensation kinetics with Hep and GSH and DNA fragmentation (TUNEL) were determined on the same sample used for ICSI. The possible relationship of decondensation parameters (maximum decondensation and decondensation velocity) and TUNEL values with ART success was evaluated. RESULTS: Embryo quality correlated positively with decondensation velocity (D60/D30) (Spearman's correlation, p < 0.05). According to D60/D30 values, patients were classified as slow decondensers (SlowD) (n = 68) or fast decondensers (FastD) (n = 61). Embryo quality was better in FastD (unpaired t test, p < 0.05). FastD and SlowD were subdivided according to use of donor oocytes. Among SlowD, biochemical and clinical pregnancy rates per transfer were significantly higher in donor (n = 19) vs. in non-donor (n = 31) cycles (Fisher's exact test, p < 0.05). TUNEL values were not related to embryo quality, but no clinical pregnancies or live births were achieved in TUNEL+ SlowD (n = 7). CONCLUSION: Decondensation kinetics of human spermatozoa in vitro with Hep and GSH could be related to embryo quality and ART success.

In vitro effects of endosulfan-based insecticides on mammalian sperm.

Endosulfan is an organochloride insecticide extensively used in several countries to protect crops from pests. As several studies indicate that endosulfan can affect human and animal development, the aim of this study was to analyse whether sperm parameters and the process of chromatin decondensation could be altered by endosulfan in mice sperm. Spermatozoa from cauda epididymis were obtained from mature male mice and incubated in the presence of two commercial formulations (CFs) of endosulfan (Master® and Zebra Ciagro®) or the active ingredient (AI) alone. A significant decrease in the percentage motility and viability of spermatozoa with respect to controls was found. In vitro decondensation was performed in the presence of glutathione and heparin. Spermatozoa incubated with the AI, endosulfan Master® and endosulfan Zebra Ciagro® showed an increase in chromatin decondensation. In addition, the TUNEL assay showed that DNA fragmentation was significantly higher when sperm were incubated with either one of the CFs when compared to the AI or controls. The ultrastructure analysis of sperm cells showed evident changes in the structure of the plasma and acrosome membranes of sperm incubated with endosulfan AI or the CFs. These results suggest that endosulfan can affect sperm integrity and in vitro chromatin decondensation as well as DNA fragmentation.

Root caries analysis in working population of 35-44 years of age (Spain).

BACKGROUND: The aim of this study was to analyse the influence of socio-demographic variables, toothbrushing frequency, frequency of snacking between meals, and tobacco and alcohol consumption, in root caries in the Spanish working population of Valencia and Murcia regions. MATERIAL AND METHODS: Cross sectional study of 458 workers 35-44 years of age, who underwent a routine work-related check-up, from June 2009 to April 2010, and were also examined, following the WHO methodology, by a calibrated dentist. Stratified random sampling. Participants fulfilled a questionnaire comprising demographic data, toothbrushing frequency, snacking frequency and tobacco and alcohol consumption. RESULTS: The DFS index (root caries) in the employed population of 35-44 years was 0.45 ± 1.3, with a root caries prevalence of 18.6% and an active root caries prevalence of 13.5%. Higher root caries prevalence and active root caries prevalence were associated with male gender, manual occupations, foreign country of origin, lower levels of education and income, lower brushing frequency and higher frequency of snacking between meals. The DFS index was associated with all studied socio-demographic variables, but gender, and it was also associated with brushing frequency. The mean number of root decayed teeth was associated with all socio-demographic variables, but country of origin, and it was also associated with brushing frequency. CONCLUSIONS: Adult workers 35-44 years of age showed worse root condition in regard to caries than general population of this age cohort. In this study, the frequency of toothbrushing and snacking between meals were the variables that influenced more in root caries.

N-acetylcysteine inhibits lipid accumulation in mouse embryonic adipocytes.

Oxidative stress plays critical roles in the pathogenesis of diabetes, hypertension, and atherosclerosis; some authors reported that fat accumulation correlates to systemic oxidative stress in human and mice, but cellular redox environment effect on lipid accumulation is still unclear. In our laboratory we used mouse embryonic fibroblasts (undifferentiated cells: CC), which are capable of differentiating into mature adipocytes (differentiated cells: DC) and accumulate lipids, as obesity model. Here we analyzed the role of the well-known antioxidant and glutathione precursor N-acetylcysteine (NAC) in cellular MAPK modulation and lipid accumulation. We evaluated the effect of NAC on the adipogenic differentiation pathway using different doses: 0.01, 0.1, 1 and 5mM; no toxic doses in these cells. A dose of 5mM NAC [DCN-5] provoked a significant decrease in triglyceride accumulation (72±10 [DCN-5] vs 169±15 [DC], p<0.01), as well in Oil Red O stained neutral lipid content (120±2 [DCN-5] vs 139±12 [DC], p<0.01). Molecular mechanisms responsible for adipogenic differentiation involve increase of the expression of phosphoERK½ and phosphoJNK, 5mM NAC treatment inhibited both pERK½ and pJNK protein levels. We also evaluated the mitotic clonal expansion (MCE) which takes place during adipogenesis and observed an increase in DC at a rate of 1.5 cells number compared to CC at day 2, whereas the highest doses of NAC significantly inhibited MCE. Our results suggest that NAC inhibits lipid accumulation and the MAPK phosphorylation in mouse embryonic fibroblasts during adipogenic differentiation and further contribute to probe the importance of cellular redox environment in adipogenesis.

GAL3ST2 from mammary gland epithelial cells affects differentiation of 3T3-L1 preadipocytes.

INTRODUCTION: In the mammary gland, the involution that occurs when lactation ends is an important period for cancer development. We have previously demonstrated stromal-epithelium interactions evaluating conditioned medium of adipose tissue on breast epithelial metalloproteases activity (Creydt et al., Clin Transl Oncol 15:124-131, 2013). Here, we evaluated the effects of conditioned medium of breast epithelial mammary cells on stromal cells. MATERIALS AND METHODS: Conditioned medium from normal murine mammary gland cell line (NMuMG) and conditioned medium proteins were obtained. Then, they were evaluated on modulation of adipocyte differentiation, using 3T3-L1 cell line. RESULTS: We described, for the first time, that breast epithelial mammary cells could produce the enzyme galactose 3-O-sulfotransferase 2 (GAL3ST2). Importantly, GAL3ST2 is present in NMMuMG and two human breast cancer cell lines, and it is more strongly expressed in more metastatic tumors. When 3T3-L1 preadipocyte differentiation was triggered in the presence of conditioned medium from NMuMG or GAL3ST2, triglyceride accumulation was decreased by 40 % and C/EBPß expression by 80 % in adipocytes. In addition, the expression of FABP4 (aP2), another marker of adipocyte differentiation, was inhibited by 40 % in GAL3ST2-treated cells. CONCLUSIONS: Taken together, these results suggest that GAL3ST2 would interfere with normal differentiation of 3T3-L1 preadipocytes; raising the possibility that it may affect normal differentiation of stromal preadipocytes and be a link to tumor metastatic capacity.

N-Acetylcysteine affects obesity-related protein expression in 3T3-L1 adipocytes.

OBJECTIVES: Oxidative stress plays critical roles in the pathogeneses of diabetes, hypertension, and atherosclerosis, but its effect on fat accumulation is still unclear. In this study, we analyzed the role of the well-known antioxidant and a glutathione (GSH) precursor N-acetylcysteine (NAC) in fat accumulation and the expression of obesity-associated proteins. METHODS: We studied the effects of 10 µM NAC on obesity-related protein expression in cultured 3T3-L1 preadipocytes, which are able to differentiate into mature adipocytes and accumulate lipids. RESULTS: NAC treatment inhibited fat accumulation and reduced the expression of obesity-related proteins, including monoamine oxidase A, heat shock protein 70 (HSP70), aminoacylase -1 (ACY-1), and transketolase. DISCUSSION: Our results suggest that the effects of NAC on triglycerides (Tgs) and protein expression are correlated. In support of this, we showed that NAC treatment affected both the Tg synthesis pathway and the expression levels of proteins implicated in human obesity.

Actuación del dentista frente a un paciente fumador / The role of dentists regarding smoker patients

En este artículo se revisa el papel del dentista en la deshabituación tabáquica con especial énfasis en el consejo sanitario y en la intervención breve. Sin embargo, no parece necesario que el dentista conozca en profundidad los distintos tipos de tratamiento y los lleve a cabo en su consulta. Si bien, en la consulta dental parecen darse todas las condiciones necesarias para realizar el tratamiento del tabaquismo. Si se decide no tratar el tabaquismo de un paciente es recomendable que tras el obligatorio consejo sanitario se le dé al paciente algún tipo de folleto con información sobre cómo dejar de fumar para que ayudar al paciente hasta éste acuda a una Unidad de Tabaquismo (AU)

This paper reviews on the role of dentists in smoking cessation, focusing in counselling and short intervention. It does not seem to be necessary for the dentist to be knowdegeable on the different treatments and to provide them at his/her practice, although the dental office seems to meet all requirements to undertake effective tobacco-cessation therapies. In case the dentist decides not to treat tobacco addiction, adequate advice should be provided and the patient offered leaflets on how to quit smoking in order to help him/her until seen at a tobacco control unit (AU)

Human adipose tissue from normal and tumoral breast regulaltes the behavior of mammary ephithelial cells

INTRODUCTION: Stromal-epithelial interactions mediate both breast development and breast cancer progression. In the present work, we evaluated the effects of conditioned media (CMs) of human adipose tissue explants from normal (hATN) and tumor (hATT) breast on proliferation, adhesion, migration and metalloproteases activity on tumor (MCF-7 and IBH-7) and non-tumor (MCF-10A) human breast epithelial cell lines. MATERIALS AND METHODS: Human adipose tissues were obtained from patients and the conditioned medium from hATN and hATT collected after 24 h of incubation. MCF-10A, MCF-7 and IBH-7 cells were grown and incubated with CMs and proliferation and adhesion, as well as migration ability and metalloprotease activity, of epithelial cells after exposing cell cultures to hATN- or hATT-CMs were quantified. The statistical significance between different experimental conditions was evaluated by one-way ANOVA. Tukey's post hoc tests were performed. RESULTS: Tumor and non-tumor breast epithelial cells significantly increased their proliferation activity after 24 h of treatment with hATT-CMs compared to control-CMs. Furthermore, cellular adhesion of these two tumor cell lines was significantly lower with hATT-CMs than with hATN-CMs. Therefore, hATT-CMs seem to induce significantly lower expression or less activity of the components involved in cellular adhesion than hATN-CMs. In addition, hATT-CMs induced pro-MMP-9 and MMP-9 activity and increased the migration of MCF-7 and IBH-7 cells compared to hATN-CMs. CONCLUSIONS: We conclude that the microenvironment of the tumor interacts in a dynamic way with the mutated epithelium. This evidence leads to the possibility to modify the tumor behavior/phenotype through the regulation or modification of its microenvironment. We developed a model in which we obtained CMs from adipose tissue explants completely, either from normal or tumor breast. In this way, we studied the contribution of soluble factors independently of the possible effects of direct cell contact (AU)

Effects of two low-shrinkage composites on dental stem cells (viability, cell damaged or apoptosis and mesenchymal markers expression).

To investigate the effects of new two low-shrinkage composites SDR(®) and Venus(®)Bulk Fill on the cell viability, cellular damage and expression of mesenchymal markers on dental stem cells. Specimens from two low-shrinkage composites were eluted with culture medium for 24 h. After 24 h of incubation, cytotoxicity of elutes were evaluated by MTT assay; apoptosis was determined using the DNA-specific fluorochrome Hoechst 33342 and the mesenchymal stem cells markers expression was analyzed by immunofluorescence staining. After 24 h of cell exposure to each extract media, dental stem cells expressed MSCs markers. The interaction among the material and cell line was not significantly correlated [F(1,60) = 2.251, P = 0.39], whereas statistically significant differences among cells lines were observed [F(1,60) = 9.157, P = 0.004], being dental pulp stem cells more resistant that periodontal ligament stem cells. Also, we did not find any significant effect between the tested materials [F(1,60) = 0.090, P = 0.765]. Furthermore, a very low proportion of exposed cells showed condensed or fragmented nuclei, typical of apoptotic cells at 24 h. The results suggest that SDR(®) and Venus(®) Bulk fill and should be considered when selecting an appropriate resin-based dental restorative material.

Heparin enhances protamine disulfide bond reduction during in vitro decondensation of human spermatozoa.

BACKGROUND: Human sperm nuclear decondensation in vivo involves protamine disulfide bond reduction by glutathione (GSH) and protamine/histone exchange, presumably with heparan sulfate (HS) as the protamine acceptor. The aim of the present study was to test the hypothesis that these two events occur simultaneously rather than sequentially, as has been hitherto accepted, and to test for the presence of HS in the human oocyte. METHODS: Spermatozoa and isolated sperm nuclei obtained from normal volunteers were exposed in vitro to heparin, the functional analogue of HS and either GSH or dithiothreitol (DTT) as the disulfide reducing agent. Decondensing reagents were added either simultaneously or sequentially. Percentage sperm nuclear decondensation was assayed by phase contrast microscopy. Thiol reduced status of isolated sperm nuclei was evaluated both indirectly [acridine orange (AO) staining of acid-denatured DNA] and directly [monobromobimane (mBBr) staining of protamine-free thiols]. The presence of HS in mature metaphase II (MII) human oocytes was analyzed by immunocytochemistry. RESULTS: Sequential addition of reagents always resulted in significantly lower decondensation if GSH was used as the disulfide bond reducer (P < 0.05 for sperm and P < 0.001 for nuclei), but only when heparin was used first, when DTT was the disulfide reducing agent (P < 0.05 for sperm and P < 0.01 for nuclei). Both AO staining of DNA and mBBr staining of protamines revealed that the addition of heparin to GSH but not to DTT significantly increased the thiol reduced status of sperm chromatin. HS was detected in the ooplasm of zona-free MII human oocytes. CONCLUSIONS: The results presented in this paper clearly show that heparin enhances the sperm chromatin thiol reducing activity of GSH in vitro, suggesting that in vivo thiol reduction and protamine/histone exchange could occur as simultaneous, rather than sequential, events. We also demonstrate for the first time the presence of HS in the human oocyte.

Elsevier Trophoblast Research Award lecture: Molecular mechanisms underlying estrogen functions in trophoblastic cells--focus on leptin expression.

The steroid hormone 17ß-estradiol is an estrogen that influences multiple aspects of placental function and fetal development in humans. During early pregnancy it plays a role in the regulation of blastocyst implantation, trophoblast differentiation and invasiveness, remodeling of uterine arteries, immunology and trophoblast production of hormones such as leptin. Estradiol exerts some effects through the action of classical estrogen receptors ERα and ERß, which act as ligand-activated transcription factors and regulate gene expression. In addition, estradiol can elicit rapid responses from membrane-associated receptors, like activation of protein-kinase pathways. Thus, the cellular effects of estradiol will depend on the specific receptors expressed and the integration of their signaling events. Leptin, the 16,000MW protein product of the obese gene, was originally considered an adipocyte-derived signaling molecule for the central control of metabolism. However, pleiotropic effects of leptin have been identified in reproduction and pregnancy. The leptin gene is expressed in placenta, where leptin promotes proliferation and survival of trophoblastic cells. Expression of leptin in placenta is highly regulated by key pregnancy molecules as hCG and estradiol. The aim of this paper is to review the molecular mechanisms underlying estrogen functions in trophoblastic cells; focusing on mechanisms involved in estradiol regulation of placental leptin expression.

Review: Leptin gene expression in the placenta--regulation of a key hormone in trophoblast proliferation and survival.

Leptin is a 16000 MW protein originally described as an adipocyte-derived signaling molecule for the central control of metabolism. However, pleiotropic effects of leptin have been identified in reproduction and pregnancy. The leptin gene is expressed in placenta, where leptin promotes proliferation and survival of trophoblast cells. Study of the major signaling pathways known to be triggered by leptin receptor has revealed that leptin stimulates JAK/STAT, MAPK and PI3K pathways in placental cells. Leptin also exerts an antiapoptotic action in placenta and this effect is mediated by the MAPK pathway. Moreover, leptin stimulates protein synthesis by activating the translational machinery via both PI3K and MAPK pathways. Expression of leptin in placenta is highly regulated, suggesting that certain key pregnancy molecules participate in such regulation. An important hormone in reproduction, hCG, induces leptin expression in trophoblast cells and this effect involves the MAPK signal transduction pathway. Moreover, the cyclic nucleotide cAMP, which has profound actions upon human trophoblast function, also stimulates leptin expression and this effect seems to be mediated by crosstalk between the PKA and MAPK signaling pathways. Estrogens play a central role in reproduction. 17ß-estradiol upregulates leptin expression in placental cells through genomic and non-genomic actions, probably via crosstalk between estrogen receptor-α and the MAPK and PI3K signal transduction pathways. Taken together these findings give a better understanding of the function of leptin and the regulatory mechanisms of leptin expression in human placental trophoblast and further support the importance of leptin in the biology of reproduction.

Prevalence of dental enamel defects in celiac patients with deciduous dentition: a pilot study.

OBJECTIVE: To describe the prevalence of unspecific and systematic enamel defects in children with deciduous dentition diagnosed with celiac disease compared with a control group. STUDY DESIGN: Thirty children (mean age 3.6 yrs) diagnosed with celiac disease and a reference group (n = 30; mean age 3.8 yrs) were studied to determine the prevalence of enamel defects. Both groups had complete deciduous dentition. Unspecific and systematic enamel defects were evaluated according to Aine criteria. RESULTS: Enamel defects were detected in 83.3% of the celiac children versus 53.3% of the control children (P = .025). The corresponding figures for symmetric defects were 73.3% and 23.3% (P < .001), respectively. The most frequent defect severity classification was Aine grade 1. Dental enamel defects were most frequently detected in deciduous molars (45.1%), followed by deciduous incisors. CONCLUSIONS: This study showed significantly more systematic enamel defects in children with celiac disease and deciduous dentition compared with a control group in the same stage of dentition. Dental examination of these defects may be useful to alert for this disease.

The presence of heparan sulfate in the mammalian oocyte provides a clue to human sperm nuclear decondensation in vivo.

BACKGROUND: Previous results from our laboratory have led us to propose heparan sulfate (HS) as a putative protamine acceptor during human sperm decondensation in vivo. The aim of this paper was to investigate the presence of glycosaminoglycans in the mammalian oocyte in an effort to better support this contention. METHODS: Two experimental approaches are used: oocyte labeling to identify the presence of HS and analysis of sperm decondensing ability of fresh oocytes in the presence or absence of specific glycosidases. RESULTS: Staining of mouse zona-intact oocytes with the fluorescent cationic dye, Rubipy, at pH 1.5 allowed for the detection of sulfate residues in the ooplasm by confocal microscopy. HS was detected in the ooplasm by immunocytochemistry. A sperm decondensation microassay using heparin and glutathione was successfully developed. The same level of sperm decondensation could be attained when heparin was replaced by mouse zona-free oocytes. Addition of heparinase to the oocyte/glutathione mixture significantly reduced sperm decondensation (P = 0.0159), while there was no effect following addition of either chondroitinase ABC or hyaluronidase. CONCLUSIONS: The results presented in this paper demonstrate for the first time that HS is present in the mammalian oocyte and show that HS is necessary for fresh oocytes to express their sperm decondensing ability in vitro.

Nuclear translocation of haeme oxygenase-1 is associated to prostate cancer.

The role of oxidative stress in prostate cancer has been increasingly recognised. Acute and chronic inflammations generate reactive oxygen species that result in damage to cellular structures. Haeme oxygenase-1 (HO-1) has cytoprotective effects against oxidative damage. We hypothesise that modulation of HO-1 expression may be involved in the process of prostate carcinogenesis and prostate cancer progression. We thus studied HO-1 expression and localisation in 85 samples of organ-confined primary prostate cancer obtained via radical prostatectomy (Gleason grades 4-9) and in 39 specimens of benign prostatic hyperplasia (BPH). We assessed HO-1 expression by immunohistochemical staining. No significant difference was observed in the cytoplasmic positive reactivity among tumours (84%), non-neoplastic surrounding parenchyma (89%), or BPH samples (87%) (P=0.53). Haeme oxygenase-1 immunostaining was detected in the nuclei of prostate cancer cells in 55 of 85 (65%) patients but less often in non-neoplastic surrounding parenchyma (30 of 85, 35%) or in BPH (9 of 39, 23%) (P<0.0001). Immunocytochemical and western blot analysis showed HO-1 only in the cytoplasmic compartment of PC3 and LNCaP prostate cancer cell lines. Treatment with hemin, a well-known specific inducer of HO-1, led to clear nuclear localisation of HO-1 in both cell lines and highly induced HO-1 expression in both cellular compartments. These findings have demonstrated, for the first time, that HO-1 expression and nuclear localisation can define a new subgroup of prostate cancer primary tumours and that the modulation of HO-1 expression and its nuclear translocation could represent new avenues for therapy.

Cell-cell communication between mouse mammary epithelial cells and 3T3-L1 preadipocytes: effect on triglyceride accumulation and cell proliferation

Interaction between parenchyma and stroma is essential for organogenesis, morphogenesis, and differentiation. Mammary gland has being the chosen model for developmental biologist because the most striking changes in morphology and function take place after birth. We have demonstrated a regulation of triglyceride accumulation by protein factors synthesized by normal mouse mammary gland epithelial cells (NMMG), acting on a cell line, 3T3-L1, long used as a model for adipogenesis. In this paper, we demonstrate that this inhibitory effect seems to be shared by other cells of epithelial origin but not by other cell types. We found a regulation of cell proliferation when NMMG cells are cultured in the presence of conditioned media from Swiss 3T3 or 3T3-L1 cells. We found a possible point of regulation for the mammary factor on a key enzyme of the lipid metabolic pathway, the glycerol-3-phosphate dehydrogenase. The inhibitory factor seems to have an effect on this enzyme's activity and reduces it. The results presented herein contribute to the understanding of cell-cell communication in a model of a normal mammary gland.

Cell-cell communication between mouse mammary epithelial cells and 3T3-L1 preadipocytes: effect on triglyceride accumulation and cell proliferation

Interaction between parenchyma and stroma is essential for organogenesis, morphogenesis, and differentiation. Mammary gland has being the chosen model for developmental biologist because the most striking changes in morphology and function take place after birth. We have demonstrated a regulation of triglyceride accumulation by protein factors synthesized by normal mouse mammary gland epithelial cells (NMMG), acting on a cell line, 3T3-L1, long used as a model for adipogenesis. In this paper, we demonstrate that this inhibitory effect seems to be shared by other cells of epithelial origin but not by other cell types. We found a regulation of cell proliferation when NMMG cells are cultured in the presence of conditioned media from Swiss 3T3 or 3T3-L1 cells. We found a possible point of regulation for the mammary factor on a key enzyme of the lipid metabolic pathway, the glycerol-3-phosphate dehydrogenase. The inhibitory factor seems to have an effect on this enzymes activity and reduces it. The results presented herein contribute to the understanding of cell-cell communication in a model of a normal mammary gland.(AU)

MDCK cells express serotonin-regulable 11beta-hydroxysteroiddehydrogenase type 2

Prior to this work, we found that adrenal as well as extra-adrenal factors activate the response of renal 11beta-hydroxysteroid dehydrogenase 2 to stressful situations. These results -showing ways through which the organism hinders the pathological occupation of mineralocorticoid receptors by glucocorticoids leading to sodium retention and hypertension- prompted the present study on the nature of the above-mentioned extra-adrenal factors. Serotonin was chosen because of its properties as a widely distributed neurohormone, known to interact with glucocorticoids at many sites, also exhibiting increased levels and effects under stressful situations. We studied serotonin effects on 11beta-hydroxysteroiddehydrogenase 2 activity in a cell line derived from distal nephronpolarized-epithelium, employing 3H-corticosterone as substrate. The end-product, 3H- 11 -dehydrocorticosterone was separated from the substrate by HPLC and quantified. Serotonin stimulated 1I beta-hydroxysteroiddehydrogenase 2 activity only at 2nM and 25pM, the magnitude of the responsedepending also on substrate concentration. The stimulation was blocked by thespecific inhibitors methiothepin and ketanserin. We postulate that the organism partially prevents renal mineralocorticoid receptor occupancy by glucocorticoids, circulating at enhanced levels under stressful situations, through serotonin-mediated catabolic regulation of the 11beta-hydroxysteroid dehydrogenase 2 activity. Given many, mostly positive, interactions between both hormones, this might eventually pave the way to studies on a new regulatory axis.

MDCK cells express serotonin-regulable 11beta-hydroxysteroiddehydrogenase type 2

Prior to this work, we found that adrenal as well as extra-adrenal factors activate the response of renal 11beta-hydroxysteroid dehydrogenase 2 to stressful situations. These results -showing ways through which the organism hinders the pathological occupation of mineralocorticoid receptors by glucocorticoids leading to sodium retention and hypertension- prompted the present study on the nature of the above-mentioned extra-adrenal factors. Serotonin was chosen because of its properties as a widely distributed neurohormone, known to interact with glucocorticoids at many sites, also exhibiting increased levels and effects under stressful situations. We studied serotonin effects on 11beta-hydroxysteroiddehydrogenase 2 activity in a cell line derived from distal nephronpolarized-epithelium, employing 3H-corticosterone as substrate. The end-product, 3H- 11 -dehydrocorticosterone was separated from the substrate by HPLC and quantified. Serotonin stimulated 1I beta-hydroxysteroiddehydrogenase 2 activity only at 2nM and 25pM, the magnitude of the responsedepending also on substrate concentration. The stimulation was blocked by thespecific inhibitors methiothepin and ketanserin. We postulate that the organism partially prevents renal mineralocorticoid receptor occupancy by glucocorticoids, circulating at enhanced levels under stressful situations, through serotonin-mediated catabolic regulation of the 11beta-hydroxysteroid dehydrogenase 2 activity. Given many, mostly positive, interactions between both hormones, this might eventually pave the way to studies on a new regulatory axis.(AU)