Mol. Hum. Reprod. Advance Access originally published online on October 22, 2004
Molecular Human Reproduction 2004 10(12):935-939; doi:10.1093/molehr/gah124
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Progesterone inhibits insulin-like growth factor binding protein-1 (IGFBP-1) production by explants of the Fallopian tube
Maternal, Fetal and Neonatal Physiology, Developmental Origins of Health and Disease Division, University of Southampton, Level F (815), Princess Anne Hospital, Coxford Road, Southampton SO16 5YA, UK
1 To whom correspondence should be addressed. Email: mcr2{at}soton.ac.uk
 |
Abstract |
|---|
 Top Abstract IntroductionMaterials and methodsResultsDiscussionReferences |
|---|
The Fallopian tube provides the environment for early embryo growth, a process which is influenced by insulin-like growth factors (IGFs) in the tubal fluid. Whether the bioavailability of tubal IGFs is modulated by locally produced IGF-binding protein (IGFBP-1) is not clear. An explant culture system from human Fallopian tube mucosa was, therefore, developed enabling the potential for IGFBP-1 production by this tissue to be examined directly. Initial characterization of the system established that the explants maintained responsiveness to steroids. Thus, oviduct-specific glycoprotein production, a major product of the oviduct in vivo, continued to be made via an estrogen-sensitive pathway in the culture. The presence of mRNA for IGFBP-1 was established within the explants by the use of quantitative RT–PCR and IGFBP-1 protein was measured by enzyme-linked immunosorbent assay. Although insulin and estradiol had no consistent effect on IGFBP-1, addition of progesterone had a significant inhibitory effect on IGFBP-1 production, both at the mRNA and protein levels. A dose-range of progesterone revealed an incremental inhibitory effect of progesterone on IGFBP-1 output (maximal effect, 25–50 nmol/l), consistent with physiological inhibition of this process during the luteal phase. We suggest that progesterone might, therefore, play a role in controlling the bioavailability of IGFs to the embryo during early development within the Fallopian tube.
Key words: Fallopian tube/IGFBP-1/oviduct-specific glycoprotein/progesterone
|
Introduction |
|---|
|
TopAbstractIntroductionMaterials and methodsResultsDiscussionReferences |
|---|
The Fallopian tube provides an environment for fertilization and early embryo development. This specific milieu is the result of activity by the tubal epithelium involving transfer and secretion of nutrients and other factors into the tubal fluid, the composition of which varies according to the phase of the menstrual cycle (reviewed by Leese et al., 2001
). It is well established that growth factors within tubal fluid have the potential to influence embryo growth and development (Kane et al., 1997). In particular, insulin-like growth factor-1 (IGF-1) has been detected in human tubal fluid, appropriate receptors have been demonstrated on human preimplantation embryos, and effects of this peptide have been measured in terms of increased survival to the blastocyst stage and greater numbers of cells developing within the inner cell mass lineage (Lighten et al., 1998). Changes in the allocation of cells to the inner cell mass of embryos (perhaps mediated through alterations in growth factors within the tubal environment) have also been demonstrated following decreased maternal nutrition in early pregnancy (Kwong et al., 2000). Furthermore, this dietary perturbation also led to later changes in blood pressure in the offspring. Taken together, these findings suggest a crucial role for growth factor availability during early embryonic life with implications for later development.
It is clear that the bioavailability of IGFs within tissues is very much influenced by the presence of the IGF-binding proteins (IGFBPs) (Rajaram et al., 1997). In this regard, many authors have stressed the particular importance of IGFBP-1, which is dynamically regulated by the action of insulin (and, therefore, indirectly influenced by diet) and is generally inhibitory to IGF action (Lee et al., 1997; Fowler et al., 2000). However, available evidence relating to the concentrations of IGFBP-1 in tubal fluid and the potential synthesis of this binding protein by the tubal mucosa is conflicting. For example, a study by Giudice et al. (1992), although demonstrating mRNA for IGFBP-2, -3 and -4 in the Fallopian tube, found that mRNA for IGFBP-1 was barely detectable, and that cultures of tubal epithelial cells did not produce observable IGFBP-1 protein as measured by Western analysis. In contrast, a study relying on immunohistochemical analysis (Pfeifer and Chegini, 1994) showed the presence of IGFBPs 1–4 in the Fallopian tube, with immunostaining greatest for IGFBP-1.
The potential effects of ovarian steroids on tubal production of IGFBP-1 compared to that in the endometrium are intriguing. In endometrial stromal cells, there is a well-established induction of IGFBP-1 production by progesterone concomitant with decidualization (reviewed by Fowler et al., 2000). Apparent localization of IGFBP-1 to the epithelial cells in the tubal mucosa, demonstrated by in situ hybridization (Julkunen et al., 1990) and immunohistochemistry (Pfeifer and Chegini, 1994; Qiu et al., 2003), points to a different cell type as the origin of IGFBP-1 in this tissue, perhaps indicating different mechanisms of control. Indeed, survival advantage to the embryo would be afforded by decreasing IGFBP-1 in the tubal environment during the time of higher circulating progesterone in the luteal phase.
The aim of the present study was to establish an explant culture system for human Fallopian tubal mucosa, which would allow the study of the effects of ovarian steroids on IGFBP-1 production. Responsiveness to steroids was characterized by the measurement of oviduct-specific glycoprotein (OGP), a major product of the oviduct, which is synthesized through an estrogen-sensitive pathway (Arias et al., 1994). Sensitive RT–PCR and enzyme-linked immunosorbent assay (ELISA) methods for detection of IGFBP-1 mRNA and protein enabled a clear demonstration that this binding protein is synthesized by the human Fallopian tube mucosa and is subject to control by ovarian steroids.
|
Materials and methods |
|---|
|
TopAbstractIntroductionMaterials and methodsResultsDiscussionReferences |
|---|
Patients
Fallopian tubes were obtained from women undergoing total abdominal hysterectomy and bilateral salpingo-oophorectomy for benign disease. Informed consent was obtained for the procedure according to a protocol approved by the local ethics committee. The age range of the women was 29–47 years (mean, 39.7 years). Histology of endometrial tissue obtained at the time of operation dated the luteal samples as being four proliferative phase and three secretory phase. Inspection of the data obtained for both OGP and IGFBP-1 output showed no consistent differences between proliferative and secretory phase samples. Consequently, values for both groups of samples were combined and averaged to obtain the data displayed.
Preparation and culture of tubal explants
The tubes were cut longitudinally to expose the mucosal folds and small ‘snips’ (0.5–1 mm in length) of these folds were taken with scissors and put into culture as explants to give approximately 60 mg of tissue per well. These were maintained in ‘Netwells’ (pore size, 74 µm; Corning Costar, High Wycombe, UK) using a mixture (50:50) of Dulbecco's modified Eagle's medium (DMEM) and Ham's F12 supplemented with glutamine (2 mmol/l), penicillin (50 mg/l), streptomycin (60 mg/l), transferrin (6.25 mg/l), selenite (6.25 µg/l) and insulin (100 ng/ml; except where omission specified). Additions were made of estradiol (E2) (10 nmol/l) and progesterone (12.5–100 nmol/l) according to experimental designs described in the figure legends. The E2 concentration was chosen after preliminary dose–response experiments found that maximal OGP production was at this concentration. The maximal progesterone concentration was the same as that used in our laboratory for work on IGFBP-1 production in decidualized endometrium (Anthony et al., 2003). Residual quantities of ethanol resulting from the original, ethanolic solutions of the steroids were <0.001% in the final culture medium, an amount which was without an effect on the parameters examined. The culture media were changed daily and stored at –20°C for later analysis. After 3 days, the explants were snap-frozen in liquid nitrogen and stored at –80°C. Representative explant samples were also taken for histology, which involved embedding in wax, the preparation of 5 µm sections, and staining with haematoxylin and eosin (Figure 1).
|
Preparation and culture of human endometrial stromal cells
Endometrial stromal cells were prepared according to a method previously described (Anthony et al., 2003
). Briefly, endometrial samples were dispersed with collagenase/dispase. Stromal cells were separated by filtration, adjusted to 5 x 105 cells/ml, and cultured in 6-well plates in DMEM/Ham's F12 supplemented with 2% (v/v) charcoal-stripped fetal calf serum. Decidualization was induced by exposure of the cultures to progesterone (100 nmol/l) for 10–14 days and indicated by transition of the cells to a larger, rounded phenotype and by the output of increasing concentrations of prolactin and IGFBP-1. After a final 24 h culture in serum-free medium (as used for the explants), with and without insulin, the medium was removed and stored at –20°C and cultured cells were taken directly into the RNA extraction procedure.
Western analysis
The conditioned media were concentrated to 10-fold by using 6 ml Vivaspin concentrator tubes (5000 MW cut-off; Sartorius, Epsom, UK). Fifteen microlitres of sample was added to 5 µl sample buffer [0.25 mmol/l Tris; 10% (w/v) sodium dodecyl sulphate (SDS); 5% (w/v) sucrose; 0.1% (w/v) bromophenol blue, pH 6.8] and heated together for 5 min (95°C) and then added to wells of polyacrylamide gels (4% stacking, 7.5% resolving; Bio-Rad, Hemel Hempstead, UK). Seven microlitres of Kaleidoscope prestained markers (Bio-Rad) was added to the final well. The gels were run at 40 V for 10 min and then at 80 V until completion, using a Tris/glycine/SDS buffer. The protein was then transferred to polyvinylidene difluoride membranes using the Mini Trans-Blot Cell (Bio-Rad) and the membranes blocked in Tris-buffered saline with Tween [TBST; 0.05 mmol/l Tris–HCl, 0.15 mmol/l NaCl, 0.1% (w/v) Tween 20, pH 7.5] containing 10% (w/v) dried milk powder. After washing in TBST, blots were exposed for 90 min to an antibody to human OGP (1:10 000 dilution), which was a gift from Prof Harold Verhage (University of Illinois). Further washing was then followed by exposure to an anti-rabbit peroxidase-conjugated secondary antibody (Sigma, Poole, UK) and then development using the ECL-Plus system (Amersham, Little Chalfont, UK). Band intensities were measured using NIH image to quantify the level of OGP production. The immunoreactivity was seen to run to a position equivalent to approximately 120 kDa, with a double-banding pattern noticeable after E2 treatment. This multiple banding is consistent with previous work and may be attributed to differential glycosylation (Verhage et al., 1988). Where double bands of immunoreactivity were apparent on the blots, the combined intensities of both the bands were taken into the calculation for quantification.
RNA extraction
Explants or cultures were homogenized on ice in 500 µl of Tri-reagent® (a monophase solution of guanidine isothiocyanate and phenol; Sigma). To the solution, 100 µl of chloroform was added; the solution was then mixed and left on ice for 10 min. The samples were then centrifuged (12 000 g) for 15 min at 4°C. The upper phase of the resulting tri-phased solution was then removed and 20 µl of glycogen solution (2 µg/µl) was added as carrier. Isopropanol (220 µl) was added and the solution was centrifuged as before. The supernatant was removed and 500 µl of 75% (v/v) ethanol was added. After centrifugation, the supernatant was removed and the resulting RNA pellet was dried at room temperature and dissolved in 20 µl of ultra-pure water to form the RNA stock solution.
cDNA synthesis and real-time PCR
Two microlitres of RNA (
1 µg) was added to 0.8 µl of random primers (500 µg/ml; Promega, Southampton, UK) and 12.2 µl of ultra-pure water. This was heated to 70°C for 5 min before being cooled on ice. The RNA was converted to cDNA using 10 µl of master mix containing reverse transcriptase (200 µg/µl M-MLV RT) and a standard nucleotide and RNase inhibitor mix. The cDNA from the reverse transcription (RT) reaction was amplified and evaluated for IGFBP-1 expression by a standard real-time PCR technique. Two microlitres of the RT reaction samples, standards or controls were assayed with a universal PCR mix (Applied Biosytems, Warrington, UK), a forward primer 5'-GGGACGCCATCAGTACCTATG-3' reverse primer 5'-GGCAGGGCTCCTTCCATTT-3' and probe 5'-FAM-CTCGAAGGCTCTCCATGTCACCAACAT-TAMRA-3' (Eurogentec, Romsey, UK) together with 2.5 µl of 18S ribosomal RNA (rRNA) mix with VIC label (Applied Biosystems). Real-time PCR was performed on an ABI Prism® 770 sequence detector (PE Biosystems, Cambridge, UK). The cycle of detection at threshold was plotted against relative RNA concentrations and IGFBP-1 was expressed relative to 18S rRNA expression.
In order to control potential contamination of cDNA with genomic DNA, two approaches were used. Firstly, the reverse primer was designed to correspond to the end of exon 2 and the beginning of exon 3 of the IGFBP-1 gene and, therefore, did not react with the genomic IGFBP-1 gene sequence containing the intervening intron. Secondly, negative controls (with no RT enzyme) were run for the RT reaction, which gave a zero reading on subsequent analysis after PCR. We conclude, therefore, that the measurement of the IGFBP-1 mRNA in this study was not influenced by contaminating genomic DNA.
ELISA for IGFBP-1
An ELISA for IGFBP-1 was developed using the ‘Duoset’ reagents supplied by R&D Systems (Abingdon, UK). Briefly, 96-well plates were coated overnight at room temperature with capture antibody [100 µl/well of a 4 µg/ml solution of mouse anti-human IGFBP-1 reconstituted in phosphate-buffered saline (PBS)] and then blocked with a solution of 5% (v/v) Tween 20 and 5% (w/v) sucrose in PBS containing 0.05% (w/v) sodium azide.
Standards were prepared using serial dilution in reagent diluent [5% (v/v) Tween 20 in PBS] to give a range of 125–4000 pg IGFBP-1/ml. One hundred microlitre aliquots of conditioned media (10 times concentrated as described for the Western analysis) or standards were added in duplicate wells and the plates were incubated at room temperature for 2 h. Following the addition of detection antibody (100 µl of 400 ng/ml biotinylated goat anti-human IGFBP-1 in reagent diluent), the plates were incubated for a further 2 h. Colour was developed using a streptavidin–horse-radish peroxidase conjugate with subsequent addition of hydrogen peroxide/tetramethylbenzidine substrate solution (R&D Systems). After stabilization of the colour with 2 M H2SO4, optical densities were read using a plate reader set at 450 nm with correction wavelength at 540 nm. The following factors at 50 ng/ml were assayed and exhibited no cross-reactivity or interference: IGF-1, IGF-2, IGFBP-2, -3, -4, -5, -6. The intra- and inter-assay variation was approximately 6 and 12%, respectively, and the limit of detection was about 60 pg/ml. After the concentration step, average levels of IGFBP-1 in control media (i.e. after culture without steroids or insulin) were approximately 1500 pg/ml, and were thus within the dynamic range of the assay.
Statistical analysis
Results from these experiments underwent statistical analysis using analysis of variance and subsequent comparison using the Student's t-test.
|
Results |
|---|
|
TopAbstractIntroductionMaterials and methodsResultsDiscussionReferences |
|---|
Explant culture system and OGP production
The explant culture system was characterized firstly through morphological assessment, which showed good preservation of cellular organization after 3 days of culture (Figure 1). Further characterization was carried out through the measurement in culture media of OGP providing an indication of the retention of function and specifically estrogen responsiveness by the culture system (Figure 2). By comparing the intensities of bands attributed to OGP after Western analysis, an estimate of OGP production was obtained for each treatment. The addition of E2 led to a significant increase in OGP production compared to control (P<0.01). The addition of progesterone alone (100 nmol/l) did not influence OGP output, but suppressed the stimulatory effect of E2. The effect of E2 with progesterone was not significantly different from control.
|
IGFBP-1 production
Figure 3 shows the progressive inhibitory effect of increasing progesterone concentrations on the output of IGFBP-1 from the tubal explant cultures, contrasted with the dramatic induction of IGFBP-1 by this steroid in the endometrial stromal cells. Figure 4 shows IGFBP-1 production by explants exposed to ovarian steroid treatments, with and without the addition of insulin to the culture medium. Measurements of IGFBP-1 protein using ELISA (Figure 4B) showed no significant effect of E2 with or without insulin, but a significant inhibitory effect by progesterone both alone and in the presence of E2 (P<0.005). This effect of progesterone was also evident when tissue concentrations of IGFBP-1 mRNA were compared (Figure 4A). There was no consistent effect of insulin on IGFBP-1 production by the explants.
|
|
The relative amounts of IGFBP-1 mRNA in the tubal explants compared with decidualized endometrial stromal cells are shown in Table I. A high expression of mRNA for IGFBP-1 is seen in the decidualized endometrial cells (cultured in the absence of insulin) when shown as a ratio with 18S RNA, and this was dramatically reduced in the presence of insulin as expected (Figure 3). Even in the absence of insulin, the expression of mRNA for IGFBP-1 was about 4-fold lower in the tubal explants compared with the insulin-suppressed level in the endometrial cells. Addition of insulin to the explant cultures of the Fallopian tube led to a marginal fall in the expression of IGFBP-1 consistent with the data in Figure 4A.
|
|
Discussion |
|---|
|
TopAbstractIntroductionMaterials and methodsResultsDiscussionReferences |
|---|
The explant culture system developed in the present study showed a number of features that recommended it for the study of human Fallopian tube function in vitro. Firstly, the good histological preservation of tissue structure after culture suggested that degenerative changes during the short-term explant culture were minimal. Secondly, a major glycoprotein product of the Fallopian tube in vivo, namely OGP, was shown to be synthesized by the explant system in an estrogen-dependent manner. These data are consistent with previous work on OGP where estrogen-dependency has been inferred from the increased level of OGP production observed in the late follicular phase in women (Verhage et al., 1988
; Arias et al., 1994) and from the marked induction of mRNA for OGP in estrogen-treated baboons (Arias et al., 1994). Our observed molecular weight (120 kDa) for OGP is similar to that previously reported (Verhage et al., 1988). The concentration of E2 used in our study (10 nmol/l) was determined by initial dose–response experiments, which showed that this concentration elicited the maximum OGP response. The observation that a physiological concentration of progesterone (100 nmol/l) was able to negate the stimulatory effect of estrogen on OGP output represents, to our knowledge, a novel finding. However, negative effects of progesterone on tubal fluid secretion have been noted previously by several authors (reviewed by Leese et al., 2001). Also, progesterone inhibits E2-maintained oviductal wet weight in rhesus monkeys (Slayden and Brenner, 1994), an effect inhibited by the progesterone antagonist, RU486. Taken together, this previous work points to a marked and generalized negative effect of progesterone on oviduct function, which is opposite to the positive effect of progesterone on endometrial function, a divergence which is amply demonstrated by the work of Slayden and Brenner (1994), where responses to progesterone of both tissues were examined within the same model. The inhibitory effect of progesterone on OGP output observed in the present study may, therefore, be a reflection of a more generalized phenomenon within the oviduct.
The potential importance of the IGFs in embryo development and the inconsistent reports surrounding the role of IGFBP-1 in modulating IGF bioavailability in the Fallopian tube have already been discussed in the Introduction. Using sensitive methods for the detection of mRNA for IGFBP-1 in tubal epithelium and IGFBP-1 in culture, we now firmly establish the ability of the Fallopian tube to contribute to IGFBP-1 concentrations within the tubal environment. Our data are consistent with a recent study demonstrating the presence in human oviduct of mRNA for IGFBP-1 by a semi-quantitative RT–PCR method and IGFBP-1 protein by immunohistochemistry (Qui et al., 2003). The finding that the level of IGFBP-1 production is many-fold lower in the tubal epithelium when compared with decidualized endometrial stromal cells (Table I) is not surprising if we consider that decidualization imparts a specialized ability to produce high concentrations of IGFBP-1. The lack of a marked inhibition by insulin of tubal IGFBP-1 production (Figure 4) contrasts with the inhibition by insulin of IGFBP-1 production by endometrial stromal cells (Table I), an inhibitory effect of insulin which is generally accepted for the main IGFBP-1 production sites in the body (Fowler et al., 2000). Clearly, the control of IGFBP-1 production in the oviduct is quite different from that in the endometrium, pointing to a fundamentally different mode of secretion from the two distinct stromal and epithelial cell types involved (see Introduction).
The finding that progesterone severely limited the capacity of the tubal explants to produce IGFBP-1, both at the mRNA and secreted protein level (Figure 4) shows a further remarkable difference between the response of tubal mucosa to this steroid and that of the endometrial stromal cells where progesterone induces a large increase in IGFBP-1 production as part of the decidualization process (Lane et al., 1994; present data Figure 3). The inhibitory effect of progesterone on tubal production of IGFBP-1 may form part of a physiological mechanism operative during the luteal phase whereby increasing concentrations of circulating progesterone (typically reaching 40–60 nmol/l) would result in reduced IGFBP-1 in the tubal environment, higher amounts of bioavailable IGF and hence potentially positive effects for embryo growth. A range of adverse effects of maternally administered, exogenous progesterone on embryo development (Barnes, 2000) are also likely to involve effects on tubal function.
As discussed earlier, progesterone has a range of inhibitory actions on oviduct function (see Leese et al., 2001), which can be reversed by RU486 in rhesus monkeys (Slayden and Brenner, 1994). A recent study (Qui et al., 2003) now extends this work on RU486 to the human oviduct and has shown that the antagonist increases the expression of IGFBP-1, a finding that is clearly consistent with the present study showing the opposite, inhibitory effect of progesterone itself. The weight of evidence thus points to a wide-ranging inhibitory effect of progesterone on oviduct function (including inhibition of IGFBP-1 production), which can be reversed by the progesterone antagonist, RU486.
An additional point of interest relevant to the present results is that IGFBP-1 tends to encourage implantation through attachment of the Arg-Gly-Asp tripeptide in IGFBP-1 with the trophoblastic integrin (Jones et al., 1993). One might speculate, therefore, that reduced synthesis of IGFBP-1 by progesterone might decrease the likelihood of tubal implantation, while increased synthesis in endometrial stroma would increase attachment at this site.
In conclusion, we have demonstrated IGFBP-1 production within the Fallopian tube and its suppression by progesterone. We suggest that this suppression might confer an advantage to the developing embryo by increasing the availability of IGF peptides within the tubal environment, thereby promoting early growth and development.
|
Acknowledgements |
|---|
We gratefully acknowledge that SD was supported by a grant to the University of Southampton from the Solent Subfertility Trust.
|
References |
|---|
|
TopAbstractIntroductionMaterials and methodsResultsDiscussionReferences |
|---|
Anthony FW, Mukhtar DD, Pickett MA and Cameron IT (2003) Progesterone upregulates WT1 mRNA and protein, and alters relative expression of WT1 transcripts in cultured endometrial stromal cells. J Soc Gynecol Investig 10, 509–516.[CrossRef][Web of Science][Medline]
Arias EB, Verhage HG and Jaffe RC (1994) Complementary deoxyribonucleic acid cloning and molecular characterization of an estrogen-dependent human oviductal glycoprotein. Biol Reprod 51, 685–694.[Abstract]
Barnes FL (2000) The effects of the early uterine environment on the subsequent development of embryo and fetus. Theriogenology 53, 649–658.[CrossRef][Web of Science][Medline]
Fowler DJ, Nicolaides KH and Miell JP (2000) Insulin-like growth factor binding protein-1 (IGFBP-1): a multifactorial role in the human female reproductive tract. Hum Reprod Update 6, 495–504.
Giudice LC, Dsupin BA, Irwin JC and Eckert RL (1992) Identification of insulin-like growth factor binding proteins in human oviduct. Fertil Steril 57, 294–301.[Web of Science][Medline]
Jones JI, Gockerman A, Busby WH, Wright G and Clemmons DR (1993) Insulin-like growth factor binding protein-1 stimulates cell migration and binds to the alpha5beta1 integrin by means of its arg-gly-asp sequence. Proc Natl Acad Sci USA 90, 10553–10557.
Julkunen M, Koistinen R, Suikkari AM, Seppala M and Janne OA (1990) Identification by hybridization histochemistry of human endometrial cells expressing mRNAs encoding a uterine beta-lactoglobulin homologue and insulin-like growth factor-binding protein-1. Mol Endocrinol 4, 700–707.
Kane MT, Morgan PM and Coonan C (1997) Peptide growth factors and pre-implantation development. Hum Reprod Update 3, 137–157.
Kwong WY, Wild AE, Roberts P, Willis AC and Fleming TP (2000) Maternal undernutrition during the pre-implantation period of rat development causes blastocyst abnormalities and programming of postnatal hypertension. Development 127, 4195–4202.[Abstract]
Lane B, Oxberry W, Mazella J and Tseng L (1994) Decidualization of endometrial stromal cells in vitro: effects of progestin and relaxin on the ultrastructure and production of decidual secretory proteins. Hum Reprod 9, 259–266.
Lee PDK, Giudice LC, Conover CA and Powell DR (1997) Insulin-like growth factor binding protein-1: recent findings and new directions. Proc Soc Exp Med 216, 319–357.
Leese HJ, Tay JI, Reischl J and Downing SJ (2001) Formation of Fallopian tubal fluid: role of a neglected epithelium. Reproduction 121, 339–346.[Abstract]
Lighten AD, Moore GE, Winston RML and Hardy K (1998) Routine addition of human insulin-like growth factor-1 could benefit clinical in vitro fertilization culture. Hum Reprod 13, 3144–3150.
Pfeifer TL and Chegini N (1994) Immunohistochemical localization of insulin-like growth factor (IGF-1), IGF-1 receptor, and IGF binding proteins 1–4 in human Fallopian tube at various reproductive stages. Biol Reprod 50, 281–289.[Abstract]
Qui X, Sun X, Christow A, Stabi B and Gemsell-Danielsson K (2003) Action of mefepristone on the expression of insulin-like growth factor binding protein-1 mRNA and protein during the early luteal phase in the human oviduct. Fertil Steril 80 (Suppl. 2), 776–782.
Rajaram S, Baylink DJ and Mohan S (1997) Insulin-like growth factor-binding proteins in serum and other biological fluids: regulation and functions. Endocr Rev 18, 801–831.
Slayden OD and Brenner RM (1994) RU486 action after estrogen priming in the endometrium and oviducts of rhesus monkeys (Macaca mulatta). J Clin Endocrinol Metab 78, 440–448.[Abstract]
Verhage HG, Fazleabas AT and Donnelly K (1988) The in vitro synthesis and release of proteins by the human oviduct. Endocrinology 122, 1639–1645.
Submitted on August 23, 2004; resubmitted on October 1, 2004; accepted on October 4, 2004.
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  M A Fenwick, S Llewellyn, R Fitzpatrick, D A Kenny, J J Murphy, J Patton, and D C Wathes Negative energy balance in dairy cows is associated with specific changes in IGF-binding protein expression in the oviduct Reproduction, January 1, 2008; 135(1): 63 - 75. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||