3-carene supresses inflammatory cytokine interleukin-4, interleukin-5 and interleukin-13 in a murine model of asthma.

Asthma is a common airway disease associated with allergic inflammation. Environmental factors, such as pollens, pollution, insect-borne antigens, or commercial chemicals, cause this disease. The common symptoms of this airway allergic reaction are increasing mucus, narrowing of the airway wall, coughing, and chest tightness. Medications, such as steroids, alleviate the disease but with severe side effects. Several studies have reported the anti-inflammatory effects of tree-based essential oil components, particularly 3-carene. Therefore, this study used 3-carene to determine if it alleviates asthmatic symptoms in the murine model. First, BALB/c mice were sensitized to an ovalbumin and aluminium hydroxide mixture on day 7th and 14th. From days 21st to 23rd, the mice were challenged with 3-carene and budesonide. The lung trachea, plasma, and bronchiolar lavage fluid (BAL fluid) were collected on day 24. The 3-carene treatment suppressed the cytokine gene expression, such as interleukin-4 (IL-4), IL-5, and IL-13, reducing the lung epithelial cell thickness in the asthmatic model. These results suggest that essential oil 3-carene has an anti-asthmatic effect.

Initial phase establishment of an in vitro method for developmental neurotoxicity test using Ki-67 in human neural progenitor cells.

Building a precise alternative neurotoxicological test is of great importance to respond to societal and ethical requirements. In this study, a new developmental neurotoxicity test (DNT) was established with the human neural progenitor cell line. ReNcell CX cells were exposed to neurotoxic chemicals (aphidicolin, hydroxyurea, cytosine arabinoside, 5-fluorouracil, and ochratoxin A) or non-neurotoxic chemicals (sodium gluconate, sodium bicarbonate, penicillin G, and saccharin). Propidium iodide (PI) was used to evaluate cell viability. BrdU and Ki-76 were employed to determine cell proliferation. Based on the cell viability and proliferation, mathematical models were built by linear discriminant analysis. Furthermore, the neurotoxic-considered chemicals inhibited cell cycle progression at the protein level, supporting the biomolecular rationale for the predictive model. Overall, these results show that the new test method can be used to determine the potential developmental neurotoxicants or new drug candidates.

Cigarette smoke extraxt influences intracellular calcium concentration in A549 cells.

Cigarette smoking is a major risk factor for pulmonary diseases, including chronic obstructive pulmonary disease (COPD) and cancer. Cigarette smoke is reported to contain over 4,000 chemical compounds. Therefore, it needs to study the effects of cigarette smoke extract (CSE) administration on intracellular calcium concentration. In this study, we investigated how CSE influences intracellular calcium concentration in human lung adenocarcinoma A549 cells. The CSE concentrations used (0.4, 2, 3%) did not influence cell viability. However, at these CSE concentrations, calcium influx transient receptor potential vanilloid 4 (TRPV4) and transient receptor potential vanilloid 6 (TRPV6) proteins significantly increased, whereas calcium efflux sodium-calcium exchanger (NCX1) and plasma membrane Ca2+ ATPase (PMCA1) proteins significantly decreased from those of the control cells. The 3% CSE treatment produced an intracellular calcium concentration higher than that of the control treatment through methods of co-transfection of pGP-CMV-GCaMP6f/CMV-R-GECO1.2 and Rhod-4 Assay. CSE induced concentration-dependent increments in hypoxia-inducible factor (HIF)-1α and HIF-2α protein levels. Moreover, phosphorylation of ERK and Akt was induced by CSE treatment. Also, mitochondrial marker B-cell lymphoma 2 (Bcl-2) protein level decreased and Bcl-2-associated X (Bax) protein level increased following CSE treatment. Also, endoplasmic reticulum (ER) stress markers BiP, CHOP, p-SAPK, and p-eIF2α levels were increased by CSE treatment. These results suggest that CSE may increase the concentration of intracellular calcium, thus increasing mitochondrial and ER stress.

Potassium-dependent sodium/calcium exchanger 3 (Nckx3) depletion leads to abnormal motor function and social behavior in mice.

Transcellular calcium transport is an essential activity in mineralized tissue formation, including that in nervous systems. Dysregulation of Ca2+ homeostasis can induce excitotoxicity and neurodegeneration in the central nervous system. Nckx3, a potassium-dependent Na+/Ca2+ exchanger, is most abundant in the brain and has a critical role in the transport of intracellular calcium across the cell membrane. However, the roles of Nckx3 in neuron development and function remain unreported. Herein, we examined the behaviors of Nckx3-knock-out mice at the age of six weeks. Detailed behavioral analyses showed Nckx3-/- mice exhibited an increase in moving distances in the open field test. Additionally, the rotarod test revealed motor learning defects in Nckx3-/- mice. Both Nckx3+/- and Nckx-/- mice also exhibited deficits in sociability and social novelty preference. Furthermore, Nckx-/- mice displayed increased depression-related behavior. However, there was no significant change in cognition function detected in Nckx-/- mice. This study demonstrates that NCKX3 is involved in behavior and neuronal function.

Demetylation of the sex-determining region Y gene promoter and incidence of disorder of sex development in cloned dog males.

Canine cloning is occasionally accompanied by abnormal sexual development. Some male donor cells produce cloned pups with female external genitalia and complete male gonadal dysgenesis, which is classified as an XY disorder of sex development (XY DSD). In this study, we examine the potential of 5-aza-2'-deoxycytidine (5-aza-dC), a DNA methyltransferase inhibitor, to reduce the phenotypic abnormality XY DSD in somatic cell nuclear transfer (SCNT)- derived pups. We used a 9-year-old normal male German Shepherd dog as a cell donor. Donor cells were treated with 10 nM 5-aza-dC for 4 days before being used for SCNT. At the same stage of cell development, significantly lower levels of DNA methylation of the sex-determining region Y (SRY) promoter was observed in the treated donor cells compared to that in the untreated cells (95.2% versus 53.3% on day 4 for the control and treated groups, respectively). No significant differences were observed in the control or treatment groups concerning fusion rate, pregnancy rate (30 days or entire period), the number of pups, or the incidence of XY DSD. However, more XY DSD dogs were observed in the control group (31.25%) than in the treatment group (14.29%). Hypermethylation of the SRY promoter was observed in the XY DSD cloned pups in both the treatment (84.8%) and control groups (91.1 ± 1.4%) compared to the methylation level in the phenotypically normal male pups of the treatment (23.2 ± 20.9%) and control groups (39.1 ± 20.1%). These results suggest that 5-aza-dC treatment of donor cells can reduce the methylation level of the SRY promoter in donor cells, and thus, 5-aza-dC is advantageous for reducing the incidence of XY DSD in canine cloning.

Second-phase validation study of an alternative developmental toxicity test using mouse embryonic stem cell-derived embryoid bodies.

The embryoid body test (EBT) is a developmental toxicity test method that measures the size of embryoid bodies (EBs) and the viability of mouse embryonic stem cells (mESCs) and fibroblasts (3T3 cells). The previous pre-validation study confirmed the high accuracy (above 80%) of EBT using 26 coded test chemicals. This second-phase validation study assessed the inter-laboratory reproducibility (5 chemicals in common) and predictive capacity (10 chemicals in each laboratory) test using the coded test chemicals at three laboratories. For the prediction model, the accuracy is increased when more data is accumulated. Therefore, we updated the prediction model and analyzed the results of the second year with the newly created-prediction model. Statistical analysis of the inter-laboratory reproducibility test results indicated that accuracy, sensitivity, and specificity were 87%, 78%, and 100%, respectively. The results of the statistical analysis of the predictive capacity test showed an accuracy of 80%, sensitivity of 78%, and specificity of 81%. In conclusion, the EBT can accurately classify various embryotoxicants within a short period and with relatively little effort. Therefore, EBT can be used as a good way to test developmental toxicity.

Uterine expression of epidermal growth factor family during the course of pregnancy in pigs.

To stably maintain pregnancy, several genes are expressed in the uterus. In particular, the endometrial expression of genes encoding growth factors appears to play a key role in maternal-foetal communication. The previous studies characterized the endometrial expression kinetics of the genes encoding epidermal growth factor (EGF), its receptor (EGFR), transforming growth factor-alpha (TGF-alpha), amphiregulin (Areg), heparin-binding (Hb) EGF and calbindin-D9k (CaBP-9k) in pigs during implantation. Here, we further characterized the expression patterns of these molecules during the entire porcine pregnancy. Porcine uteri were collected at pregnancy days (PD) 12, 15, 30, 60, 90 and 110 and subjected to RT-PCR. EGF and EGFR showed similar expression patterns, being highly expressed around implantation and then disappearing. TGF-alpha and Areg expression levels rose steadily until they peaked at PD30, after which they gradually decreased to PD12 levels. This Areg mRNA expression pattern was confirmed by real-time PCR and similar Areg protein expression patterns were observed. Immunohistochemical analysis of PD60 uteri revealed Areg in the glandular and luminal epithelial cells. Hb EGF was steadily expressed throughout the entire pregnancy, while CaBP-9k was expressed strongly on PD12, and then declined sharply on PD15 before recovering slightly for the remainder of the pregnancy. Thus, the EGF family may play a key role during implantation in pigs. In addition, CaBP-9k may help to maintain uterine quiescence during pregnancy by sequestering cytoplasmic Ca(2+).

Melatonin influences the expression and oligomerization of amylin in rat INS-1E cells.

The present study investigated whether melatonin influences the expression/oligomerization of amylin with endoplasmic reticulum (ER) stress in rat insulinoma INS-1E cells. No change in cell survival after exposure to thapsigargin- and tunicamycin-combined melatonin treatment or melatonin-only treatment was observed when compared with the normal control cells. With thapsigargin-only or combined tunicamycin-melatonin treatments, phosphorylation of extracellular signal-regulated kinase (ERK) was significantly increased compared with control and melatonin-only treatments. A significant increase was observed in the levels of ER stress markers, namely, phosphorylated inositol-requiring protein 1α (p-IRE1α), CCAAT enhancer binding proteins (C/EBP)-homologous protein, p-eukaryotic translation initiation factor 2α and cleaved caspase-12, in the thapsigargin-combined melatonin-treated cells as compared with the tunicamycin-combined or only melatonin treatment. The melatonin-only treatment resulted in increased levels of amylin expression/oligomerization in 15-25 kDa and insulin proteins, compared with the thapsigargin- and tunicamycin-combined melatonin treatments. Treatment with ER stress inhibitor 4-phenylbutyric acid (4-PBA) did not suppress amylin expression/oligomerization or insulin production with thapsigargin or tunicamycin treatment. Levels of cleaved caspase-12 were significantly decreased in the thapsigargin- or tunicamycin-4-PBA combination treatments. Therefore, whether melatonin regulates the amylin expression/oligomerization in thapsigargin- or tunicamycin-combined with Bafilomycin A1 (autophagy inhibitor) or MG132 (proteasome inhibitor) treatments were investigated. Amylin expression/oligomerization with melatonin treatment was significantly decreased in the thapsigargin- or tunicamycin-combined Bafilomycin A1 or MG132 treatments. Since these outcomes are involved in cell viability, they indicate that increased cell death leads to decreased amylin expression/oligomerization, however, the effects of melatonin treatment on amylin expression/oligomerization induce proliferation of pancreatic ß cells and improve the cellular functions of pancreatic ß cells.

Inhibitory effect of octyl-phenol and bisphenol A on calcium signaling in cardiomyocyte differentiation of mouse embryonic stem cells.

Endocrine-disrupting chemicals (EDCs) have structures similar to steroid hormones and can interfere with hormone synthesis and normal physiological functions of reproductive organs. For example, sex steroid hormones influence calcium signaling of the cardiac muscle in early embryo development. To confirm the effect of progesterone (P4), octyl-phenol (OP), and bisphenol A (BPA) on early differentiation of mouse embryonic stem cells (mESCs) into cardiomyocytes, mESCs were treated with P4, OP, and BPA two days after attachment and media were replaced every two days. In addition, cells were treated with mifepristone (RU486), a synthetic steroid that has an affinity for progesterone receptor (Pgr), for one day starting on day 11. Beating ratio was decreased with P4, OP, and BPA treatment. The Pgr mRNA level was significantly increased in the P4-, OP- and BPA-treated groups. However, the mRNA level of the calcium channel gene (Trpv2), contraction-related genes (Ryr2, Cam2, and Mylk3) and cardiac development and morphogenesis genes (Rbp4, Ly6e, and Gata4) were significantly decreased in the P4-, OP-, and BPA-treated groups. Interestingly, treatment with RU486 rescued the altered calcium channel gene, contraction-related genes, and cardiac development and morphogenesis genes. P4, OP, and BPA treatments reduced the intracellular calcium level. Taken together, these results indicate that EDCs (OP and BPA) has a structure similar to that of endogenous steroid hormones such as progesterone and estrogen, and OP and BPA act like progesterone to inhibit and disrupt cardiomyocyte differentiation of mESCs.

Regulatory effect of dexamethasone on tracheal calcium processing proteins and mucosal secretion.

Dexamethasone inhibits mucin secretion considering the primary option for treating acute asthma exacerbation. However, the mechanism underlying dexamethasone-induced decreased in mucosecretion is unclear. Recent studies have reported that dexamethasone exerts an inhibitory effect on mucosecretion in the lung by modulating the expression of calcium processing genes. However, the expression of the calcium processing genes in the trachea is not examined yet. Thus, the present study is the first to report the localization of calcium processing proteins such as transient receptor potential vanilloid-4 (Trpv4), transient receptor potential vanilloid-6 (Trpv6), calbindin-D9k (CaBP-9k) and plasma membrane Ca2+-ATPase 1 (Pmca1) in the mouse trachea and their glucocorticoid-induced response. In this study, mice were subcutaneously injected with dexamethasone for 5 days, and their tracheal samples were collected by dividing the trachea into the cervical, and thoracic sections based on its anatomical structure. The localization of TRPV4, TRPV6, CaBP-9k, and PMCA1 proteins was detected in the tracheal epithelium, submucosal glands, cartilages and muscles. Dexamethasone treatment downregulated the mRNA expression of the four calcium processing genes and mucin producing genes. The dexamethasone-induced decrease in the secretion of mucosubstances in the trachea was determined by performing Alcian blue-periodic acid-Schiff staining. Thus, the findings of the present study suggest that glucocorticoids simultaneously can regulate the expression of calcium processing genes and tracheal mucosecretion.

Anti-asthmatic effects of volatile organic compounds from Chamaecyparis obtusa, Pinus densiflora, Pinus koraiensis, or Larix kaempferi wood panels.

Asthma is a common chronic inflammatory disease in which lung airways narrow and produce extra mucus. Numerous medications, such as steroids, are used to prevent or control asthmatic symptoms, but side effects are associated with those medications. There are reports of anti-inflammatory, antibacterial, and antiparasitic effects of terpene, a volatile organic compound (VOC) in conifers. VOCs easily enter a gaseous form, and wood products are good sources of VOCs. However, only a few studies have been conducted on the effect on asthma of VOCs emitted by wood. In this study, we examined the effects of VOCs diffused from wood panels on ovoalbumin (OVA)-induced asthma in a mouse model. The mice were intraperitoneally sensitized with 10 µg of OVA with aluminum hydroxide on days 0, 7, and 14. From day 21 to day 26, the mice were challenged with 2% OVA intranasally for 30 min. For VOC treatment, asthma model mice were placed in polyacrylamide chambers containing wood panels of Chamaecyparis obtusa, Pinus densiflora, Pinus koraiensis, or Larix kaempferi. On day 27, serum, lung tissue, and bronchoalveolar lavage fluids were prepared for H&E staining, qRT-PCR, ELISA, and Diff-Quik staining, as appropriate. OVA treatment induced hypertrophy of the bronchiolar wall. The budesonide group and all four of the wood panel-exposed groups showed less thickening of the bronchiolar wall and downregulated transcriptional expressions of cytokines such as interleukin-4 (IL-4) and interleukin-13 (IL-13). The serum tumor necrosis factor-α (TNF-α) mRNA expression level was significantly decreased only in the C. obtusa group, but the serum IL-4 levels were decreased in all wood panel treatment groups. Diff-Quik staining of bronchoalveolar lavage fluids revealed a decrease in the number of granulocytes in all wood panel treatment groups. The results suggest that VOCs from C. obtusa, P. densiflora, P. koraiensis and L. kaempferi produce antiasthmatic effects by regulating the production of IL-4, IL-9, IL-13, TNF-α.

Assessment of neurotoxicity of pharmacological compounds during early neural development of human embryonic stem cells.

Human embryonic stem cells (hESCs), with the potential for differentiation, have been used to evaluate the embryotoxicity of various compounds. The effects of pharmacological compounds (cytosine arabinoside, 5-fluorouracil, hydroxyurea, indomethacin, and dexamethasone) on neurogenesis of hESCs over 28 days were examined based on cytotoxicity (half-maximal inhibitory concentration of viability, IC50) and expression of neural markers. Cytosine arabinoside, 5-fluorouracil, and hydroxyurea showed strong cytotoxicity (IC50 < 10 µM), whereas indomethacin and dexamethasone had weaker cytotoxic effects. Dose-dependent expression profiles of neural markers in the compound-treated groups are presented in triangular charts to allow comparison with the standard expression levels in the control group. Differences in compound-specific reductions in expression patterns of GAD1, OLIG2, FABP, and NES were similar to the differences in cytotoxic strength. Cytosine arabinoside diminished nestin and ß3-tubulin in neural differentiated hESCs. The results of this study extend the understanding of how differentiated hESCs may be useful for assessment of cell viability or neurogenesis impairment by chemicals that could have effects during the embryonic stage, particularly during neurogenesis.

Serum Concentrations of Leptin and Adiponectin in Dogs with Myxomatous Mitral Valve Disease.

BACKGROUND: The concentrations of circulating adipokines in dogs with myxomatous mitral valve disease (MMVD) have not been investigated in detail. OBJECTIVES: To determine whether serum concentrations of adipokines differ between healthy dogs and dogs with MMVD and whether circulating concentrations depend on the severity of heart failure resulting from MMVD. ANIMALS: In the preliminary study, 30 healthy dogs and 17 client-owned dogs with MMVD, and in the subsequent study, 30 healthy dogs and 46 client-owned dogs with MMVD. METHODS: Prospective case-controlled observational study. In the preliminary study, serum concentrations of leptin, adiponectin, resistin, visfatin, interleukin (IL)-1ß, IL-6, IL-10, IL-18, and tumor necrosis factor-α were measured. In the subsequent study, MMVD dogs were divided into three groups according to the International Small Animal Cardiac Health Council (ISACHC) classification, and serum concentrations of leptin and adiponectin were measured. RESULTS: In the preliminary study, serum leptin and adiponectin concentrations differed significantly between dogs with MMVD and healthy dogs. Serum leptin (P = .0013) concentrations were significantly higher in dogs with MMVD than in healthy dogs, whereas adiponectin (P = .0009) concentrations were significantly lower in dogs with MMVD. However, we observed no significant differences in the other variables. In the subsequent study, dogs classified as ISACHC class 3 had higher serum concentrations of leptin (P = .0022) than healthy dogs but ISACHC class 1 or 2 dogs did not. Serum adiponectin concentrations were significantly lower in ISACHC class 1 (P < .0001) dogs than in healthy dogs, whereas adiponectin concentrations in ISACHC class 3 dogs were significantly higher than in ISACHC class 1 dogs (P = .0081). CONCLUSIONS AND CLINICAL IMPORTANCE: Circulating concentrations of leptin and adiponectin might be altered in dogs with MMVD.

The human calbindin-D9k gene. Complete structure and implications on steroid hormone regulation.

The gene encoding the human calbindin-D9k has been cloned and the complete sequence established. The gene spans about 5.5 kilobases and is localized on the X-chromosome, consists of three exons and carries four Alu repeats. The promoter and 1300 base-pairs of 5' flanking region have been characterized. Besides a TATA box and two CAAT-like motifs a sequence related to a vitamin D response element was detected about 1.1 kilobases upstream from the promoter. A sequence positioned 50 nucleotides downstream from the promoter showed extensive homology to the estrogen response element at the same location within the rat calbindin-D9k gene. Two essential nucleotides within this region are changed when the rat and human sequences are compared. The human element failed to bind the estrogen receptor as determined by gel retardation assay. It is proposed that a two-nucleotide change within this region causes the gene to lack expression in human uterus and possibly placenta.

Expression of the type II activin receptor gene in the human placenta.

Activin has been suggested to be an autocrine/paracrine regulator in the human placenta. In the present study, we examined the expression of the gene encoding activin type II receptor (ActRII) in this tissue. Using primers corresponding to the published sequence of human ActRII, a 456bp fragment was obtained from cDNAs prepared from the placenta, as well as the ovary and brain, by polymerase chain reaction (PCR). Southern blot hybridization of the PCR products and DNA cloning and sequencing confirmed that the product is the authentic ActRII. Trophoblast cells prepared from both first trimester and term placentae expressed the ActRII gene. When trophoblast cells from term placenta were separated into syncytiotrophoblast- and cytotrophoblast-enriched fractions and incubated for 1-6 days, ActRII gene expression was observed in both cell preparations, with the syncytiotrophoblast-enriched fraction having higher levels of expression at days 1, 3, and 4. These results provide the first direct evidence that the activin type II receptor mRNA is present in human trophoblast cells and strengthen the hypothesis that activin is an autocrine/paracrine regulator of placental function. To our knowledge, this is also the first report that the ActRII gene is expressed in the human brain and ovary.

Human peripheral blood mononuclear cells express gonadotropin-releasing hormone (GnRH), GnRH receptor, and interleukin-2 receptor gamma-chain messenger ribonucleic acids that are regulated by GnRH in vitro.

The hypothalamic decapeptide, GnRH, plays a critical role in human reproduction. In addition to the well known effects of GnRH on pituitary cells, there is evidence supporting the presence of GnRH-binding sites in tissues other than pituitary cells, including lymphocytes. In addition, a GnRH-like substance has been found to be secreted from lymphoid cells. However, the precise nature of GnRH secretion and binding in immune cells has not been fully established. In this study, we used the RT-PCR method to examine the expression and regulation of GnRH, GnRH receptor (GnRHR), and interleukin-2 receptor gamma-chain messenger ribonucleic acids (mRNAs) in human peripheral blood mononuclear cells. It was found that human mononuclear cells expressed GnRH and GnRHR mRNAs. Nucleotide sequences of these mRNAs are identical to their hypothalamic and pituitary counterparts, respectively. In addition, GnRH and GnRHR mRNA expressions in peripheral blood mononuclear cells are regulated by GnRH and its synthetic analogs in vitro. Treatment with various concentrations of GnRH (10(-5)-10(-11) mol/L) increased GnRHR mRNA expression in a dose-dependent manner (maximal level is 158% of the untreated control value at 10(-8) mol/L GnRH; P < 0.05), but reduced GnRH mRNA levels to 69% of the untreated control value at 10(-9) mol/L GnRH (P < 0.05). Cotreatment of GnRH with a GnRH antagonist blocked these regulatory effects, indicating the receptor-mediated nature of the GnRH action. Both GnRH and GnRH agonist stimulated interleukin-2 receptor gamma-chain mRNA in a dose-dependent manner, indicating that GnRH may be involved in lymphocyte activation. In summary, these observations suggest that mRNAs encoding the pituitary form of GnRHR and the hypothalamic form of GnRH are also expressed in human peripheral blood mononuclear cells. The endogenous production of GnRH by lymphocytes may act as an autocrine or paracrine factor to regulate immune functions. Because of the presence of GnRHR on lymphocytes, exogenous GnRH analog therapy may have an impact on the immune system through these receptors.

Molecular cloning of the full-length cDNA encoding the human calbindin-D9k.

The full-length cDNA encoding the human calbindin-D9k (CaBP-9k) has been cloned using reverse transcription/PCR methodology with rat- and bovine-derived primers and intestinal RNA. A core product, and both a 5' and 3' product encompassing the full-length cDNA were obtained. The clones include coding region for 79 amino acids, 57 nucleotides 5'-and 159 nucleotides 3'-non-coding region, and a poly(A) tail. The deduced protein sequence is homologous to other mammalian CaBPs. Northern analysis revealed the mRNA in human duodenum to be about 600 nucleotides in length. Expression levels in adult human tissue were substantially lower than in child, rat or porcine intestine.

Calbindin-D9k gene expression during pregnancy and lactation in the rat.

Calbindin-D9k (CaBP-9k) is a calcium binding protein expressed in mammalian intestine, uterus and placenta. It is believed to be involved in transepithelial calcium transport in intestine and placenta and regulation of cytosolic calcium concentration in uterus. CaBP-9k mRNA levels were measured by Northern blot analysis in maternal duodenum, uterus, placenta and fetal/neonatal duodenum during pregnancy and lactation. In maternal duodenum a maximal increase occurred at day 15 of lactation (2.3-fold) and 20 days post-lactation levels decrease to 30.3% of non-pregnant controls. In non-pregnant uterus a 10-fold variation of CaBP-9k mRNA levels was observed between individual animals despite a uniform expression of beta-actin. During pregnancy high CaBP-9k expression is found, averaging about 20% of duodenal levels, which abruptly drops below detection during early lactation. At late lactation CaBP-9k mRNA levels are again subject to great variation ranging from no expression to maximal levels found in the non-pregnant uterus. Placental CaBP-9k is maximally expressed at the end of pregnancy (day 20) reaching about 2.5% of duodenal levels. Fetal intestinal CaBP-9k mRNA was detectable in 20 micrograms total RNA at day 18 of pregnancy and rose sharply in early lactation reaching about 50% of adult duodenal levels at day 20 lactation. The profound changes of uterine CaBP-9k mRNA in non-pregnant (cycling), pregnant, and lactating rats indicate a rapid hormonal regulation of gene expression, most likely involving 17 beta-estradiol.

Calbindin-D9k mRNA is tightly regulated during the estrous cycle in the rat uterus.

Calbindin-D9k (CaBP-9k) is a cytosolic calcium binding protein with a molecular weight of 9000. CaBP-9k is mainly expressed in intestine, uterus and placenta, with intestinal levels controlled by vitamin D and uterine levels controlled by estrogens. CaBP-9k mRNA levels were measured in rat uterus throughout the estrous cycle. On the morning of proestrus, estrus and diestrus animals were sacrificed. Serum 17 beta-estradiol concentrations were determined using a radioimmunoassay. Whole uterus was used for preparation of total RNA. Northern blot analysis was performed to quantify CaBP-9k and beta-actin mRNA. CaBP-9k levels were highest at proestrus, dropped 10-fold at estrus and were not detectable at diestrus. beta-Actin levels did not change significantly throughout the estrous cycle. Peak 17 beta-estradiol concentrations coincided with maximum CaBP-9k mRNA expression at proestrus. Despite minimal concentrations of 17 beta-estradiol at estrus, CaBP-9k mRNA was still present at 10% of the proestrus level. At diestrus, CaBP-9k mRNA was not detectable despite increasing 17 beta-estradiol. It is concluded that CaBP-9k is subject to 17 beta-estradiol regulation during the estrous cycle. Correlation between CaBP-9k mRNA and 17 beta-estradiol levels indicates a lag period for CaBP-9k induction in diestrus following a rise in steroid hormone levels.

The human gonadotropin-releasing hormone (GnRH) receptor gene: cloning, genomic organization and chromosomal assignment.

The cDNA encoding the gonadotropin-releasing hormone (GnRH) receptor has recently been cloned and characterized in several species, including human. To determine the structure of the gene encoding the human GnRH receptor, we have screened a human genomic library and isolated seven positive clones, using cDNA probes derived from a human pituitary cDNA library. The isolated genomic clone contains the entire protein coding region of the GnRH receptor which is distributed between three exons and spans over 18.9 kb. Sequence analysis and restriction endonuclease mapping revealed the presence of two introns of 4.2 and 5.0 kb, respectively, both located within the open reading frame, designating the human GnRH receptor gene to the intron-containing class of the G-protein coupled receptor superfamily. Genomic Southern blot analysis indicated the presence of a single copy of the gene encoding for the GnRH receptor within the human genome. Using DNA from human-hamster somatic hybrid cell lines, the GnRH receptor gene was assigned to human chromosome 4, by means of PCR. The present study represents the first report on the GnRH receptor gene and its partial characterization should facilitate further investigation of the mechanisms by which expression of this gene is regulated.