Fingolimod induces neurogenesis in adult mouse hippocampus and improves contextual fear memory.

Fingolimod (FTY720) was the first per os administered disease-modifying agent approved for the treatment of relapsing-remitting multiple sclerosis. It is thought that fingolimod modulates the immune response by activating sphingosine-1 phosphate receptor type 1 (S1P1) on lymphocytes following its in vivo phosphorylation. In addition to its immune-related effects, there is evidence that fingolimod exerts several other effects in the central nervous system, including regulation of the proliferation, survival and differentiation of various cell types and their precursors. In the present study, we have investigated the effect of fingolimod on the production of new neurons in the adult mouse hippocampus and the association of this effect with the ability for pattern separation, an established adult neurogenesis-dependent memory function. Immunofluorescence analysis after chronic administration of a physiologic dose of fingolimod (0.3 mg kg(-1)) revealed a significant increase in both the proliferation and the survival of neural progenitors in the area of dentate gyrus of hippocampus, compared with control animals. These effects were replicated in vitro, in cultures of murine hippocampal neural stem/precursor cells that express S1P1 receptor, suggesting cell-autonomous actions. The effects of fingolimod on neurogenesis were correlated to enhanced ability for context discrimination after fear conditioning. Since impairment of adult hippocampal neurogenesis and memory is a common feature of many neuropsychiatric conditions, fingolimod treatment may be beneficial in therapeutic armamentarium of these disorders.

Predictive and prognostic value of LPS-stimulated cytokine secretion in metastatic non-small cell lung cancer.

OBJECTIVE: Cancer patients usually develop malnutrition which may alter their innate immune system integrity. The aim of this study was to investigate the clinical relevance of chemokine response after lipopolysaccharide (LPS)-stimulation in metastatic non-small cell lung cancer (NSCLC). METHODS: Blood samples from metastatic NSCLC patients were incubated with LPS before the onset of systemic therapy. Interleukin (IL)-6 and IL-8 levels at baseline and after LPS-stimulation were measured and the fold change compared to baseline levels was evaluated as the stimulation index for each cytokine per patient. Results were correlated with sex, age, smoking status, histologic subtype, performance status (PS), albumin, Mini Nutritional Assessment (MNA) status and clinical outcomes. RESULTS: Totally 103 patients were evaluated. Mean (±SD) stimulation index was 37.6 (±57.8) for IL-6 and 76.7 (±133.4) for IL-8. The disease control rate after first-line chemotherapy was 44/80 (55 %) and the mean (±SD) progression-free survival (PFS) and overall survival (OS) were 4.2 (±3.9) and 9.2 (±1.1) months, respectively. MNA, PS, albumin, IL-6 and IL-8 stimulation indices were univariately associated with PFS and OS. IL-8 stimulation index emerged as an independent predictor of both PFS and OS, along with PS, and albumin levels. CONCLUSION: The extent of IL-6 and IL-8 stimulation after ex vivo induction with LPS is an important predictor of clinical outcome in metastatic NSCLC patients.

Treatment of experimental murine colitis with CD40 antisense oligonucleotides delivered in amphoteric liposomes.

BACKGROUND AND AIMS: CD40-CD40L interactions appear to play an important role in the pathogenesis of experimental colitis. We tested the effect and investigated the underlying mechanism of action of systemically administered antisense oligonucleotide (ASO) targeting CD40 formulated in amphoteric liposomes (nov038/CD40). The charge characteristics of the amphoteric liposomes (anionic surface charge at physiological pH that becomes cationic at low pH), facilitate efficient sequestration of the ASO inside the liposomes at low pH and the direction of the carriers towards macrophages and dendritic cells under physiological conditions. METHODS: Colitis was induced in Balb/c mice using 2,4,6-Trinitrobenzene sulphonic acid (TNBS) and treated with nov038/CD40. Disease was monitored by body weight, histology, cytokine profiling and changes in immune cell populations. CD40 expression on different cell subsets was analyzed by flow cytometry. An antigen challenge model was used to determine neoimmunity under CD40 modulation. RESULTS: Administration of nov038/CD40 inhibited the development of TNBS colitis as assessed by weight loss, histology and cytokine profiles; unformulated CD40 ASO or nov038 encapsulating an unrelated ASO (nov038/SCR) were ineffective. The novel agent is potent as it completely suppressed even established colitis with a single treatment and significantly reduced T-cell activation as well as levels of pro-inflammatory mediators in serum. The inhibition of CD40 specifically occurred in macrophages, but not in B-cells. In contrast to prednisolone, standard treatment for inflammatory bowel diseases (IBD) that is effective in a single administration and involves extensive immunosuppression, nov038/CD40 did not affect the number of B- or Treg cells. Eventually, we observed a largely intact neoimmunity under conditions of a CD40 inhibition. CONCLUSIONS: Administration of nov038/CD40, but neither naked CD40 ASO nor nov038/SCR, prevents the development and treats established colitis in mice. Delivery of CD40 ASO in nov038 is highly cell-specific as it selectively suppresses CD40 on macrophages, but not on B-cells; the novel agent has strong anti-inflammatory characteristics without being immunosuppressive.

Correlation between serum 25-hydroxyvitamin D levels and quadriceps muscle strength in elderly cretans.

Vitamin D deficiency is associated with osteomalacic myopathy, and muscle weakness related to vitamin D deficiency has been implicated as a possible risk factor for falls in the elderly. This study investigated the possible correlation between serum 25-hydroxyvitamin D (25[OH]D) concentration and quadriceps muscle strength in ambulatory community dwelling Cretan men (n=13) and women (n=35) aged > or = 65 years. Quadriceps muscle strength was measured isometrically using Cybex 6000 apparatus. The mean serum 25(OH)D concentration was significantly higher in men than in women (76.00 versus 49.11 nmol/l, respectively). Serum 25(OH)D values were < 50 nmol/l in 15% of men and in 60% of women. Serum 25(OH)D concentration correlated positively with quadriceps muscle strength. In conclusion, vitamin D deficiency was common in the study participants despite the high levels of sunlight in Crete. Serum 25(OH)D levels were positively correlated with muscle strength.

The corticotropin-releasing factor (CRF) family of peptides as local modulators of adrenal function.

Corticotropin-releasing factor (CRF), also termed corticotropin-releasing hormone (CRH) or corticoliberin, is the major regulator of the adaptive response to internal or external stresses. An essential component of the adaptation mechanism is the adrenal gland. CRF regulates adrenal function indirectly through the central nervous system (CNS) via the hypothalamic-pituitary-adrenal (HPA) axis and via the autonomic nervous system by way of locus coeruleus (LC) in the brain stem. Accumulating evidence suggests that CRF and its related peptides also affect the adrenals directly, i.e. not through the CNS but from within the adrenal gland where they form paracrine regulatory loops. Indeed, CRF and its related peptides, the urocortins (UCNs: UCN1, UCN2 and UCN3), their receptors CRF type 1 (CRF(1)) and 2 (CRF(2)) as well as the endogenous pseudo-receptor CRF-binding protein (CRF-BP) are all expressed in adrenal cortical, medullary chromaffin and resident immune cells. The intra-adrenal CRF-based regulatory system is complex and depends on the balance between the local concentration of CRF ligands and the availability of their receptors.

Corticotropin-releasing factor (CRF) and the urocortins differentially regulate catecholamine secretion in human and rat adrenals, in a CRF receptor type-specific manner.

Corticotropin-releasing factor (CRF) affects catecholamine production both centrally and peripherally. The aim of the present work was to examine the presence of CRF, its related peptides, and their receptors in the medulla of human and rat adrenals and their direct effect on catecholamine synthesis and secretion. CRF, urocortin I (UCN1), urocortin II (UCN2), and CRF receptor type 1 (CRF1) and 2 (CRF2) were present in human and rat adrenal medulla as well as the PC12 pheochromocytoma cells by immunocytochemistry, immunofluorescence, and RT-PCR. Exposure of dispersed human and rat adrenal chromaffin cells to CRF1 receptor agonists induced catecholamine secretion in a dose-dependent manner, an effect peaking at 30 min, whereas CRF2 receptor agonists suppressed catecholamine secretion. The respective effects were blocked by CRF1 and CRF2 antagonists. CRF peptides affected catecholamine secretion via changes of subplasmaliminal actin filament polymerization. CRF peptides also affected catecholamine synthesis. In rat chromaffin and PC12 cells, CRF1 and CRF2 agonists induced catecholamine synthesis via tyrosine hydroxylase. However, in human chromaffin cells, activation of CRF1 receptors induced tyrosine hydroxylase, whereas activation of CRF2 suppressed it. In conclusion, it appears that a complex intraadrenal CRF-UCN/CRF-receptor system exists in both human and rat adrenals controlling catecholamine secretion and synthesis.

Dehydroepiandrosterone sulfate and allopregnanolone directly stimulate catecholamine production via induction of tyrosine hydroxylase and secretion by affecting actin polymerization.

Adrenal cortical cells of zona reticularis produce the neuroactive steroids dehydroepiandrosterone (DHEA), its sulfate ester dehydroepiandrosterone sulfate (DHEAS), and allopregnanolone (ALLO). An interaction between zona reticularis and adrenal medulla has been postulated based on their close proximity and their interwoven borders. The aim of this paper was to examine in vitro the possible paracrine effects of these steroids on catecholamine production from adrenomedullary chromaffin cells, using an established in vitro model of chromaffin cells, the PC12 rat pheochromocytoma cell line. We have found the following: 1) DHEA, DHEAS, and ALLO increased acutely (peak effect between 10-30 min) and dose-dependently (EC50 in the nanomolar range) catecholamine levels (norepinephrine and dopamine). 2) It appears that the acute effect of these steroids involved actin depolymerization/actin filament disassembly, a fast-response cellular system regulating trafficking of catecholamine vesicles. Specifically, 10(-6) m phallacidin, an actin filament stabilizer, completely prevented steroid-induced catecholamine secretion. 3) DHEAS and ALLO, but not DHEA, also affected catecholamine synthesis. Indeed, DHEAS and ALLO increased catecholamine levels at 24 h, an effect blocked by L-2-methyl-3-(-4-hydroxyphenyl)alanine and 3-(hydrazinomethyl)phenol hydrochloride, inhibitors of tyrosine hydroxylase and L-aromatic amino acid decarboxylase, respectively, suggesting that this effect involved catecholamine synthesis. The latter hypothesis was confirmed by finding that DHEAS and ALLO increased both the mRNA and protein levels of tyrosine hydroxylase. In conclusion, our findings suggest that neuroactive steroids exert a direct tonic effect on adrenal catecholamine synthesis and secretion. These data associate the adrenomedullary malfunction observed in old age and neuroactive steroids.

Body mass index (BMI) and parameters of bone formation and resorption in postmenopausal women.

OBJECTIVES: Aim of this study was to evaluate increased body mass index (BMI) as an anthropometric factor, predisposing to lower rates of bone turnover or changes in bone balance after menopause. MATERIAL AND METHODS: For this purpose, we calculated BMI, and measured spinal (BMD(SP)) and femoral bone mineral density (BMD(FN)) and biochemical markers of bone formation (serum osteocalcin (S-OC), serum procollagen type I C propeptide (S-PICP), serum bone-specific alkaline phosphatase (S-B-ALP)) and resorption (urine N- and C-terminal cross-linking telopeptide of type I collagen (U-NTX-I and U-CTX-I), pyridinoline (U-PYD) and deoxypyridinoline (U-DPD)) in 130 healthy postmenopausal women, aged 46-85 years. Bone balance indices were calculated by subtracting z-scores of resorption markers from z-scores of formation markers, to evaluate bone balance. RESULTS: S-PICP ( r = -0.297, P = 0.002), S-OC ( r = -0.173, P = 0.05) and bone balance indices (zPICP-zDPD) and (zPICP-zPYD) were negatively correlated with BMI (r = -0.25, P = 0.01 and r = -0.25, P = 0.01 and r = -0.21, P = 0.037) and with BMD(SP) (r = -0.196, P = 0.032 and r = -0.275 and P = 0.022). Women were grouped according to their BMI, in normals (BMI < 25 kg/m2), overweight (BMI = 25-30 kg/m2, and obese (BMI > 30 kg/m2). Overweight and obese women had approximately 30% lower levels of S-PICP compared to normals (68.11 +/- 24.85 and 66.41 ng/ml versus 97.47 +/- 23.36 ng/ml, respectively; P = 0.0001). zPICP-zDPD, zPICP-zCTX-I and zPICP-zPYD were significantly declined in obese women compared to normals (P = 0.0072, 0.02 and 0.0028). CONCLUSIONS: We conclude that in postmenopausal women, BMI is inversely associated with levels of collagen I formation marker, serum PICP. In obesity formation of collagen I was reduced, in favor of degradation, but since this finding is not followed by simultaneous decrease in bone mineral density, it seems that increased body weight may have different effects on mature estrogen-deficient bone and extraskeletal tissues containing collagen I.

Effects of doxycycline, metronidazole and their combination on Candida species colonization of the human oropharynx, intestinal lumen and vagina.

The present study reports about the effect of doxycycline and/or metronidazole on colonization by Candida organisms of the human gastrointestinal (GI), oropharyngeal tract and vagina. Treatment with doxycycline or metronidazole for 10 days increased, but not significantly, the GI, oropharyngeal or vaginal colonization by Candida species. The combination of doxycycline and metronidazole, used for the same period, caused a significant increase of 2.5 log10 CFU/g of stools (mean) colonization by Candida. Likewise, 2 out of 9 patients treated with the combination had substantially increased colonization of their vagina by Candida species. This effect, however, could not be expressed statistically due to the semiquantitative nature of the vaginal cultures. In contrast, the combination did not increase oropharyngeal colonization. In conclusion, doxycycline and metronidazole as monotherapies, did not increase significantly Candida colonization in the cavities examined. The combination of doxycycline and metronidazole had a substantial effect, increasing the GI and vaginal colonization by Candida organisms.

Transforming growth factor beta1 exerts an autocrine regulatory effect on human endometrial stromal cell apoptosis, involving the FasL and Bcl-2 apoptotic pathways.

Transforming growth factor beta1 (TGFbeta1) is expressed in human endometrium. It regulates epithelial cell proliferation and apoptosis. The aim of the present work was to examine the role of TGFbeta1 on human endometrial stromal cell apoptosis. Primary cultures of isolated stromal cells were obtained from biopsies of late secretory phase endometrium. We have found the following: (i) TGFbeta1 induced apoptosis of stromal cells in a time- and dose-dependent manner; (ii) blockade of TGFbeta1's autocrine/paracrine effect by TGFbeta1-neutralizing antibodies diminished the basal rate of stromal cell apoptosis; (iii) semi-quantitative Western blot analysis showed that TGFbeta1 caused a rapid but transient elevation of the pro-apoptotic FasL protein, without affecting the levels of Fas receptor; (iv) TGFbeta1 increased the levels of the anti-apoptotic Bcl-2 and Bcl-xL proteins, while having no significant effects on the pro-apoptotic proteins Bax and Bak, suggesting the activation of a transient survival mechanism activated in stromal cells as a parallel rescue response to the apoptosis-inducing FasL protein. In conclusion, our data provide evidence that TGFbeta1 exerts an autocrine pro-apoptotic effect on human endometrial stroma, via the FasL/Fas system.

Urocortin in human gastric mucosa: relationship to inflammatory activity.

The presence of CRH and urocortin (Ucn), members of the CRH family of neuropeptides, was examined in human gastric biopsies from normal controls and in patients with active gastritis from Helicobacter pylori (H. pylori) and after eradication treatment. RT-PCR analysis showed the presence of the Ucn transcript in biopsies (obtained by gastroscopy) from normal and inflamed gastric mucosa, whereas the CRH transcript was not detectable. Immunoreactive (ir-) Ucn was localized (by immunohistochemistry) in gastric epithelial cells and in inflammatory elements of the surrounding negative for Ucn gastric stroma. The level of ir-Ucn was higher in gastric biopsies from the group of patients with active H. pylori gastritis than in normal controls (10.4 +/- 1.8 vs. 2.0 +/- 1.3 pg/ micro g total protein; P < 0.001). After the apparent eradication of H. pylori infection (by clinical and morphological criteria) ir-Ucn levels increased dramatically to 43.1 +/- 9.8 pg/ micro g total protein, (P < 0.001) compared with pretreatment values. Interestingly, nonresponders to the eradication treatment did not show any significant change in ir-Ucn levels (18.7 +/- 12.3 pg/ micro g total protein) compared with their pretreatment values. In conclusion, our data suggest that in human gastric epithelium Ucn is present and plays an important physiological role, whereas CRH is absent. In addition, and in contrast to what has been found for CRH in ulcerative colitis, a highly significant, but negative, correlation has been found between Ucn levels and gastric inflammation, suggesting that Ucn may exert an antiinflammatory effect in gastric mucosa.

Effects of erythromycin, clarithromycin, roxithromycin and azithromycin on murine gut colonization by Candida albicans.

Male Crl:CD1(ICR) BR mice were fed either chow containing Candida albicans or regular chow. The gastrointestinal tract of the C. albicans-fed mice was permanently colonized by the yeast. Groups of C. albicans-colonized mice were subsequently treated either with a macrolide (erythromycin, clarithromycin, roxithromycin or azithromycin) for 10 days or a normal saline solution (controls). Other controls included non-colonized mice receiving the same antibiotics or a saline solution. Our data are as follows: (i) C. albicans-colonized mice treated with each macrolide had highly significant increase in colony counts of C. albicans in their stools compared to C. albicans-colonized mice treated with saline only; (ii) discontinuation of macrolide treatment showed a trend towards lower colony counts, which was not statistically significant (colony counts were sustained even after discontinuation of antibiotic treatment); (iii) dissemination of C. albicans did not occur; (iv) mice fed regular chow treated with the study drugs or saline did not have any yeasts in their stools. In conclusion, oral erythromycin, clarithromycin, roxithromycin and azithromycin cause a modest increase of the C. albicans concentration of the gastrointestinal tract. This increase is not associated with a higher risk of disseminated candidiasis.

Expression and regulation of corticotropin-releasing hormone binding protein (CRH-BP) in rat adrenals.

Corticotropin-releasing hormone (CRH) is present in the adrenal gland acting as a paracrine factor via stimulation of the locally expressed CRH receptors. In this study, we examined if the adrenal CRH system also contains a key component of the neuronal CRH-containing system, the CRH-binding protein (CRH-BP). Our data show that: (i) the CRH-BP transcript is detectable using RT-PCR in total RNA isolated from rat adrenals, and (ii) its protein product is also found by western blot analysis in cell lysates. (iii) Immunohistochemical staining showed that adrenomedullary chromaffin cells produce the bulk of adrenal CRH-BP, an ability retained by the PC12 rat pheochromocytoma cell line. (iv) Regulation of adrenal CRH-BP expression by major modulators of the CRH system was also examined. Protein expression appears to be under the positive control of CRH itself, protein kinase A effector cAMP, glucocorticoids and interleukin (IL)-6. It is thus evident that CRH-BP may play a role in mediating their effects in the adrenal. (v) Differentiation of PC12 into neuron-like cells resulted in a significant increase in CRH-BP, parallel to the induction of the CRH peptide itself. In conclusion, CRH-BP mRNA and protein are present in normal rat adrenomedullary chromaffin cells and in the PC12 rat pheochromocytoma cell line, making the adrenal CRH system directly comparable with those described in the CNS.

Increased levels of lipoprotein (a) in Crohn's disease: a relation to thrombosis?

OBJECTIVE: Lipoprotein (a) is recognized as a risk factor for arterial and venous thrombosis, a property that might be related to its structural similarity to plasminogen. Since patients with inflammatory bowel disease frequently suffer from thromboembolic events, we studied the role of lipoprotein (a) in conjunction with lipids and apolipoproteins in Greek patients with ulcerative colitis and Crohn's disease. METHODS: Lipoprotein (a), total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglycerides, apolipoprotein A-1 and apolipoprotein B-100 were determined in sera from 129 consecutive fasting Greek patients with inflammatory bowel disease (66 with ulcerative colitis and 63 with Crohn's disease) and from 66 matched healthy controls. RESULTS: In Crohn's disease patients, the mean serum lipoprotein (a) level was significantly higher than in control patients (41.2 mg/dl vs 22.9 mg/dl; P = 0.005). Mean apolipoprotein A-1 and apolipoprotein B-100 levels were significantly lower in Crohn's disease patients than in the controls. In ulcerative colitis patients the mean levels of lipoprotein (a) and apolipoprotein A-1 were not significantly different to the controls, but the levels of apolipoprotein B-100 were significantly lower. Raised levels of lipoprotein (a) of > 30 mg/dl were found in 29 Crohn's disease patients (46%), 15 ulcerative colitis patients (23%) and 11 control patients (17%). Patients with active Crohn's disease had significantly higher mean lipoprotein (a) and lower apolipoprotein A-1 than patients with non-active disease. CONCLUSIONS: Our results suggest that Crohn's disease patients have different lipoprotein (a) and apolipoprotein patterns compared to ulcerative colitis patients and healthy controls. These changes in Crohn's disease patients may possibly expose them to a higher risk of thrombosis.

Corticotropin-releasing hormone promotes blastocyst implantation and early maternal tolerance.

The semi-allograft embryo in the blastocyst stage implants itself in the endometrium, yet no immune rejection processes are activated. Embryonic trophoblast and maternal decidua produce corticotropin-releasing hormone (CRH) and express Fas ligand (FasL), a proapoptotic cytokine. We found that antalarmin, a CRH receptor type 1 antagonist, decreased FasL expression and promoted apoptosis of activated T lymphocytes, an effect which was potentiated by CRH and inhibited by antalarmin. Female rats treated with antalarmin showed a marked decrease in implantation sites and live embryos and diminished endometrial FasL expression. Embryos from mothers that lacked T cells or from syngeneic matings were not rejected when the mothers were given antalarmin. These findings suggested that locally produced CRH promotes implantation and maintenance of early pregnancy primarily by killing activated T cells.

The Fas/FasL apoptotic pathway is involved in kappa-opioid-induced apoptosis of human endometrial stromal cells.

Human endometrium expresses specific kappa-opioid binding sites and their endogenous ligands, the dynorphins. In neural crest-derived tissues, kappa-opioids affect apoptosis, a phenomenon of major significance in endometrial stroma physiology. Our hypothesis was that endometrial kappa-opioids may play a role in endometrial stromal cell apoptosis. Thus, we examined the effect of the synthetic kappa-opioid agonist, U69593, on the apoptotic rate of human endometrial stromal cells in primary culture. Apoptosis of endometrial stromal cells was elevated after 3 h exposure to 100 nmol/l U69593, and remained elevated for up to 3 days. This effect was dose-dependent and was reversed by the general opioid antagonist, naloxone, suggesting that it is mediated via opioid receptors. In parallel, semi-quantitative Western blot and flow cytometry analysis showed that U69593 caused a rapid but transient up-regulation of Fas protein, suggesting that its effect on apoptosis is mediated by activation of the Fas/FasL apoptotic pathway. Additionally, U69593 increased the content of the anti-apoptotic members of the Bcl-2 family of proteins, the Bcl-2 and Bcl-x(L), whereas it had no significant effect on the apoptosis-promoting homologues Bax, Bcl-x(S) and Bak. This implies that a transient survival mechanism is activated in stromal cells as a parallel rescue response to the apoptosis-inducing factor. In conclusion, our data suggest that endometrial opioid dynorphins may participate in the apoptotic processes related to endometrial tissue remodelling during early pregnancy or menstruation.

Endometrial and myometrial corticotropin-releasing hormone (CRH): its regulation and possible roles.

In human endometrium, both epithelial and stroma cells produce corticotropin-releasing hormone (CRH). Both types of cells also possess specific CRH-binding sites indicating a local effect of endometrial CRH. The transcription of the CRH gene in human endometrium is under the control of steroid hormones and locally produced prostanoids and interleukins. Endometrial CRH interacts with locally produced prostaglandins and interleukins. Based on these observations it can be hypothesized that CRH, prostaglandins and interleukins form a network responsible for the communication between epithelial and stromal cells, at the level of the endometrium, and between endometrial and myometrial cells at the level of uterus. The net product of these interaction is the micro-regulation of the decidualizing process and the preparation of endometrium for the implantation/nidation of the conceptus. Indeed, this network may represent the core of the intrauterine neuroendocrine-immune interactions involved in the decidualization of stroma and implantation of blastocyst. In addition, this network appears to be essential for the fine-tuning of myometrial tone.

Cycle and age-related changes in corticotropin-releasing hormone levels in human endometrium and ovaries.

Corticotropin-releasing hormone (CRH) is synthesized in most female reproductive tissues such as the ovaries and the uterus. In the non-pregnant uterus, it is mainly produced by epithelial cells of the endometrium. Recent in vitro experimental findings show that endometrial CRH is under the positive control of progesterone, participating in the decidualization process of endometrial stroma and the progression of blastocyst implantation. CRH is also produced in the thecal compartment of the human ovary, controlling ovarian steroid hormone biosynthesis. In the present study we compared the concentration of immunoreactive CRH (ir-CRH) in biopsies from proliferative and secretory human endometria, and from pre- and postmenopausal human ovaries. We found that the concentration of ir-CRH was significantly higher in the secretory (92 +/- 8 pg/mg protein; n = 10) than the proliferative (75 +/- 9 pg/mg protein; n = 12; p < 0.05) endometria. This observation supports the experimental in vitro findings associating endometrial CRH in intrauterine phenomena of the secretory phase of the menstrual cycle (decidualization and implantation). Additionally, we have shown that the concentration of ir-CRH was significantly higher in the premenopausal (125 +/- 12 pg/mg protein; n = 14) than the postmenopausal (100 +/- 12 pg/mg protein; n = 12; p < 0.05) ovaries, suggesting that ovarian CRH is related to normal ovarian function during the reproductive lifespan.

Opioids suppress basal and nicotine-induced catecholamine secretion via a stabilizing effect on actin filaments.

Catecholamine secretion and actin filament disassembly are closely coupled in chromaffin cells. Opioid suppression of catecholamine secretion is fast and transient, both characteristics of actin filament involvement. The aim of the present work was to test the hypothesis that opioids suppress catecholamine secretion via an inhibitory effect on actin filament disassembly. For this purpose we used the PC12 rat pheochromocytoma cell line. Norepinephrine and dopamine were measured by enzyme-linked immunosorbent assay or RIA. Polymerized actin was measured by rhodamine-phalloidin and visualized by confocal laser scanning microscopy. Opioids suppressed basal catecholamine secretion. The onset of this effect was fast and transient, peaking at 2 min, and was reversible by opioid antagonists. Synchronously, opioids suppressed actin filament disassembly; this was also reversible by opioid antagonists. Cytochalasin B prevented the inhibitory effect of opioids on catecholamine secretion. In addition, opioids suppressed the stimulatory effect of nicotine on catecholamine secretion and actin depolymerization. Changes in actin cytoskeleton in neuron-like PC12 cells make them resistant to both effects of opioids, i.e. on catecholamine secretion and actin disassembly. In conclusion, our data suggest that the suppressive effect of opioids on basal and nicotine-induced catecholamine secretion may result from an opioid-provoked stabilization of cortical actin. It also appears that basal catecholamine secretion is associated with opioid-sensitive machinery regulating the continuous formation of short-lived areas of cortical actin filament disassembly.