| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
Other Original Articles |
The Sir Quinton Hazel Research Center for Molecular Medicine, Department of Biological Sciences, University of Warwick (E.K., H.S.R., D.K.G., E.W.H.), Coventry, United Kingdom CV4 7AL; Center for Reproductive Sciences, University of California (R.B.J.), San Francisco, California 94143
Address all correspondence and requests for reprints to: Prof. E. W. Hillhouse, Department of Biological Sciences, University of Warwick, Coventry, United Kingdom CV4 7AL. E-mail: eh{at}dna.bio.warwick.ac.uk
Abstract
Hormones produced by the fetal adrenal regulate fetal growth,
steroidogenic activity, and intrauterine homeostasis, which are
essential for the maintenance of pregnancy and the preparation of the
fetus for extrauterine life. There is a functional interaction between
CRH and the fetal adrenal, as CRH increases dehydroepiandrosterone
sulfate production in cultured fetal adrenal cells. Moreover, in a
rodent model administration of orexin A induced corticosterone
production. To examine this relationship in more detail we measured the
expression of the different subtypes of CRH and orexin receptors and
their specific coupling to G protein 
-subunits upon activation with
CRH and orexin A, respectively. Using RT-PCR and fluorescent in
situ hybridization analysis, we demonstrated the presence of
CRH receptors 1 and 2, and orexin type 2 receptor mRNA. None of
the other CRH receptor variants or orexin type 1 receptor were
detected. Immunofluorescent analysis and Western blotting confirmed the
protein expression of both receptors, which also bind
fluo-CRH and fluo-orexin with high
affinity. Immunoblotting analysis confirmed the expression of
prepro-orexin and orexin A in fetal adrenals. Using photoaffinity
labeling, we determined which G proteins are coupled to the CRH and
orexin receptors in fetal adrenals when challenged with CRH or orexin.
Treatment of fetal adrenal membranes with CRH (100 nM)
increased the labeling of Go and, to a lesser extent,
Gs, but not Gi and Gq, whereas
treatment with orexin A (100 nM) increased the labeling of
Gs and Gi, but not Go and
Gq. These findings provide new insights into the components
of the signal transduction machinery in human fetal adrenals and
demonstrate for the first time the presence of functional orexin
receptors outside of the CNS in humans.
THE ORIGIN OF the signal for the onset of labor is poorly understood, whether pregnancy ends at term or prematurely. In sheep the onset of labor depends upon an intact fetal-hypothalamo-pituitary adrenal axis, indicating that the fetus has a major role in influencing the length of gestation (1). The decrease in sheep placental progesterone toward term is due to the rise in fetal cortisol secretion, which stimulates the placental enzyme P450 C17 lyase, thereby converting progesterone to E (2). Although human fetal cortisol increases toward term, the human placenta lacks P450 C17 lyase, leading to normal production of progesterone in late human gestation (3, 4).
In humans, maternal plasma CRH concentrations increase exponentially as pregnancy advances, reaching levels as high as 800 pg/ml during the third trimester and becoming undetectable within 24 h of delivery (5). The major source of this CRH that is secreted into both the maternal and fetal circulation is the placenta (6). It has been proposed that this process is analogous to a placental clock, which triggers the onset of parturition after a predetermined length of gestation, and that the maternal plasma CRH is an indicator of the rate of progress toward this event (7).
As pregnancy progresses, circulating fetal concentrations of CRH reach levels of 200–300 pg/ml (5). This placenta-derived CRH stimulates dehydroepiandrosterone sulfate (DHEAS) production by the fetal adrenal complex (8) both directly and indirectly via stimulation of fetal pituitary ACTH. DHEAS is converted to E by the placenta, stimulating effectors of labor such as gap junctions, PGs, oxytocin, and the oxytocin receptor in the maternal myometrium, events necessary for successful uterine contractions and parturition (8).
CRH exerts its actions by binding to two different families of
CRH receptors, termed CRH-R1 and CRH-R2 (9, 10). The
CRH-R1 receptor is 415 amino acids in length and has several
variants: CRH-R1ß, which contains an additional 29 amino acids in the
first intracellular loop (9); CRH-RC, which has a 40-amino
acid deletion in the N-terminal domain of the receptor
(11); and CRH-R1D (12), which has a 14-amino
acid deletion within the seventh transmembrane domain. There are three
known forms of the CRH-R2 receptor, CRH-R2 (13, 14),
CRH-R2ß (13), and CRH-R2
(15), each of
which has a different N-terminus generated by 5'-differential exon
splicing.
Recently, two novel orexogenic agents, termed orexins A and B, have been cloned from the rat hypothalamus and shown to be up-regulated during fasting (16). These orexins exert their actions via two different G protein-coupled receptors, namely orexin 1 (OX1R) and orexin 2 (OX2R) receptors, which display 64% homology at the amino acid level in humans (16). OX2R is a nonselective receptor for both peptides, whereas OX1R is selective for orexin A. In a rodent model, both orexin A and orexin B raised basal corticosterone secretion by adrenocortical cells through activation of adenylate cyclase (17). Moreover, the rise in corticosterone secretion independent of ACTH stimulation in starved rats (18) supports a direct regulatory function for the adrenal in energy homeostasis.
In this study we tested the hypothesis that there is a direct functional interaction of CRH and orexin at the fetal adrenal level by determining the expression of the different subtypes of CRH and orexin receptors and their signal transduction characteristics in human fetal adrenals.
Subjects and Methods
Total RNA preparation and cDNA synthesis
Human fetal adrenal glands were obtained from second trimester fetuses after elective termination of pregnancy by dilatation and evacuation. Samples were washed in PBS and immediately snap-frozen in liquid nitrogen. Total RNA was prepared from individual samples using the RNeasy Total RNA Kit (QIAGEN, Crawley, UK) according to the manufacturer’s guidelines. First strand cDNA synthesis was performed using ribonuclease reverse transcriptase (Life Technologies, Inc., Paisley, UK).
PCR
All PCR reactions were carried out using Taq DNA
polymerase (Life Technologies, Inc.) with 200 ng cDNA for
each amplification, as previously described (19).
Similarly, four different sets of primers were used for the detection
of the CRH-R2 (20), using human pregnant myometrium
cDNA as a positive control. The set of primers for amplification of the
OX2R was 5'-TAGTTCCTCAGCTGCCTATC-3' and 5'-CGTCCTCATGTGGTGGTTCT-3'. The
set of primers for the amplification of the orexin type-1 receptor was
5'-CCTGTGCCTCCAGACTATGA-3' and 5'-ACACTGCTGCATTCCATGAC-3'. Ten
microliters of the reaction mixture were subsequently electrophoresed
on a 1.2% agarose gel and visualized by ethidium bromide, using a 1-kb
DNA ladder (Life Technologies, Inc.) to estimate the band
sizes. As a negative control for all of the reactions, distilled water
was used in place of the cDNA. The resultant PCR products were
sequenced in an automated DNA sequencer, and the sequence data were
analyzed using Blast Nucleic Acid Database Searches from the National
Center for Biotechnology Information.
Fluorescent in situ hybridization (FISH)
Paraffin-embedded sections of human fetal adrenals were dewaxed and dehydrated by successive washes through ethanol, then air-dried. Specific 40-mer synthetic oligonucleotide probes with fluorescein conjugated at their 5'-ends were used in this study. Hybridization solution (100 µl) containing 1 ng/µl probe was allowed to hybridize at 37 C overnight. Slides were then placed in preheated (45 C) 2 x SSC (standard saline citrate) buffer, in which they were washed twice, followed by another 10-min immersion in 0.1 x SSC (45 C). The tissue sections were rinsed with PBS for 5 min, and the cell nuclei were visualized by applying the DNA-specific dye 4,6-diamido-2-phenylindole at a final concentration of 1 µg/ml.
Imuunofluorescence
Paraffin-embedded sections of fetal adrenals were dewaxed and dehydrated using the same procedure as that used for FISH, described above. The primary goat polyclonal CRH-R1/2 and OX2R antibodies (Santa Cruz Biotechnology, Inc., Santa Cruz, CA) were used at a 1:100 dilution. All dilutions were made in 3% BSA in PBS. Specimens were incubated with primary antibody for 60 min and then washed three times with PBS, 5 min each time, before incubation with antigoat IgG-fluorescein isothiocyanate-conjugated secondary antibody (Santa Cruz Biotechnology, Inc.) for the CRH-R1/2 for 45 min. Similarly, a Texas Red antigoat IgG secondary antibody was used for the detection of OX2R. The tissue sections were thoroughly rinsed with PBS, and the cell nuclei were visualized by applying the DNA-specific dye 4,6-diamido-2-phenylindole at a final concentration of 1 µg/ml.
Binding studies using fluo-CRH and fluo-orexin
Paraffin-embedded tissue sections were dewaxed and dehydrated as described above. After dehydration, tissue sections were incubated with isotonic buffer containing 50 mM Tris-HCl (pH 7.4), 10 mM MgCl2, 1% BSA (wt/vol), and 1 mg/ml bacitracin for 10 min at room temperature. The isotonic buffer was then aspirated, and the sections were incubated with 40 nM fluo-CRH (NEN Life Science Products, Boston, MA) and Fluo-orexin (Phoenix Pharmaceuticals, Inc., Belmont, CA) in the same isotonic buffer at room temperature for 2 h in a dark humidified chamber. Nonspecific binding was assessed by including a 100-fold excess of unlabeled CRH/orexin in parallel incubations. After incubation, the tissue sections were rapidly washed for 1 min in rinsing buffer containing 50 mM Tris-HCl (pH 7.4) and 10 mM MgCl2 at 4 C, then air-dried under a cool stream of air. This procedure was repeated four times. After thorough washes, coverslips were mounted onto the slides using 90% glycerol/PBS. The slides were then examined using a Nikon Microphot FX microscope (Melville, NY) using specific density filters for fluorescein.
Western blotting
Fetal adrenal membranes (100 µg) were centrifuged at 13,000 rpm for 15 min at 4 C. The supernatant was then discarded, and the resultant pellets were solubilized with Laemmli buffer (5 M urea, 0.17 M SDS, 0.4 M dithiothreitol, and 50 mM Tris-HCl, pH 8.0), mixed, placed in a boiling water bath for 5 min, and allowed to cool at room temperature.
Samples were separated on an SDS-10% polyacrylamide gel, and the proteins were electrophoretically transferred to a nitrocellulose filter at 250 mA for 16–18 h in a transfer buffer containing 20 mM Tris, 150 mM glycine, and 20% methanol. The filter was then blocked in PBS containing 0.1% Tween 20 and 5% dried milk powder (wt/vol) for 2 h at room temperature. After three washes with PBS-0.1% Tween, the nitrocellulose filters were incubated with primary antibody for CRH-R1/2, OX2R (Santa Cruz Biotechnology, Inc.), and OR-A (Phoenix Pharmaceuticals, Inc.). The primary antiserum was used at a 1:1000 dilution in PBS-0.1% Tween for 1 h at room temperature. The filters were washed thoroughly for 30 min with PBS-0.1% Tween before incubation with the secondary antirabbit horseradish peroxidase-conjugated Ig (1:2000) for 1 h at room temperature and further washing for 30 min with PBS-0.1% Tween. Antibody complexes were visualized as previously described (21).
Synthesis of [-32P]GTP-azidoanilide
([-32P]GTP-AA) and photoaffinity labeling of
-subunits
GTP-AA was synthesized using a method previously described (12). Fetal adrenal membranes (150–200 µg) were incubated for 3 min at 30 C with CRH and orexin A (100 nM) in buffer C (50 mM HEPES, 30 mM KCl, 10 mM MgCl2, 1 mM benzamidine, and 0.1 mM EDTA), followed by the addition of 5 µM GDP and 6 µCi GTP-AA. After incubation for 3 min at 30 C in a darkened room, membranes were placed on ice and collected by centrifugation at 13,000 rpm for 15 min at 4 C. The supernatant was carefully removed, and the membrane pellet was resuspended in 120 µl modified buffer C (1.6 mg DTT in 5 ml buffer C). Samples were vortexed and irradiated for 5–10 min at 4 C with a UV light (254 nm) from a distance of 5 cm to cross-link the GTP-AA to the G proteins. Immunoprecipitation using 10 µl undiluted G protein antiserum was then carried out as previously described (21).
Statistical analysis
Data are shown as the mean ± SEM of each measurement. In each case results were evaluated between groups using two-tailed t test, with significance determined at the level of P < 0.05. Statistical ANOVA was also performed measuring the intensity of immunoreactive staining using a scanning densitometer (Scion Image, Frederick, MD).
Results
PCR and sequence analysis
Using primers that reverse transcribe the full-length CRH-1
subtype together with each of the type 1 receptor splice variants, we
amplified a DNA fragment of 1.3 kb from the fetal adrenal samples (Fig. 1
, A, panel I). We were unable to detect
any of the splice variants in this tissue. Nested PCR amplification
using specific primers for the CRH type 2 receptor subtypes resulted in
the detection only of CRH-R2 in the fetal adrenals (Fig. 1, A, panel
II). None of the other type 2 receptor subtypes were detected. These
primers were able to detect the CRH-R2 in human pregnant myometrium,
which was used as a positive control.
|
, panel III), but were unable to identify any transcript
for the OX1R. Neither of the orexin receptors was present in human
reproductive tissues: placenta, myometrium (nonpregnant and pregnant),
amnion, or chorion. Sequence analysis confirmed the identity of all PCR
products. Western blotting analysis
To determine the apparent mol wt of the membrane-bound CRH-Rs in
fetal adrenals, SDS-PAGE of membrane proteins was performed using an
antibody raised against a peptide corresponding to amino acids 425–444
in the C-terminus of the human CRH-R1/2 precursor. Given the homology
of the region, this particular antibody cannot distinguish between the
different receptor subtypes. A protein with an apparent molecular mass
of 52–54 kDa was detected in preparations from fetal adrenals (Fig. 1B). The specificity of the response was confirmed by preincubation of
the CRH-R1/2 antibody with the blocking peptide.
Protein expression of OX2R in human fetal adrenal membrane preparations
was also confirmed by immunoblotting using a specific goat polyclonal
antibody raised against a peptide mapping at the amino-terminus of the
OX2R of human origin (Fig. 1C). The detected protein has a molecular
mass of approximately 38 kDa, although a band with an apparent
molecular mass of 46 kDa was also detectable. To determine whether
orexin is expressed in adrenal tissues, we used immunoblotting with a
specific antibody capable of recognizing both prepro-orexin A and the
mature peptide. We confirmed the presence of both prepro-orexin (15
kDa) and the cleaved orexin A (3.5 kDa) in fetal adrenal glands,
raising the possibility of an autocrine action of the peptide (Fig. 1D).
FISH and immunofluorescence analysis
Next, we used FISH to localize the cellular distribution of the
CRH-R1 and OX2R in fetal adrenals. The signal was dispersed
throughout the fetal zone (Fig. 2, C–F).
Similar results were obtained for the expression of the CRH-R2 (data
not shown). No specific staining was detected when a sense
oligonucleotide probe was used.
|
, G–J). Binding study using fluo-peptides
Intense dispersed staining was visualized when fetal adrenal cells
were incubated with fluo-CRH and fluo-orexin
(Fig. 2, A and B). No staining was visualized when excess nonlabeled
CRH or orexin was added (data not shown).
Photoaffinity labeling with GTP-AA
To determine which G proteins are coupled to the CRH-Rs in
human fetal adrenals, we used GTP-AA to label G protein -subunits
activated by CRH (100 nM). Fetal adrenal membranes were
labeled with GTP-AA in the presence or absence of CRH, and the
-subunits of various G-proteins (i.e.
Gs, Gq,
Gi, and Go) were
immunoprecipitated. A significant amount of GTP-AA was incorporated
into -subunits even in the absence of agonist. Treatment of fetal
adrenal membranes with CRH increased the labeling of
Gs and Go, but not
Gi and Gq (Fig. 3). Quantification of the amount of
radioactivity bound by immunoprecipitated -subunits is shown in Fig. 3. The exact second messenger mechanism by which OX2R exerts its
actions is not fully understood. To determine which G proteins are
coupled to the OX2R in fetal adrenal membranes, we used GTP-AA to label
G protein -subunits activated by orexin A (100
nM). Using this nonhydrolysable analog GTP-AA, we
demonstrated for the first time that OX2R can couple to multiple G
proteins in fetal adrenals when challenged with orexin A. Treatment of
fetal adrenal membranes with orexin A increased the labeling of
Gs and, to a lesser degree
Gi, but not Gq and
Go (Fig. 4).
|
|
The results presented in this study confirm that human fetal
adrenal cells express CRH receptors (8) and extend these
observations to show that only the subtypes, 1 and 2, are
expressed at the mRNA and protein levels. Moreover, the data presented
here provide conclusive evidence for the presence of orexin A and OX2R
receptors, but not OX1R, in human fetal adrenals. Our results are
consistent with a recent study that has demonstrated the expression of
OX2R, but not OX1R, in the rat adrenal gland (22).
The apparent molecular mass of fetal adrenal CRH receptors (55 kDa) in
our study, as determined by Western blotting, is comparable to that
proposed for the human, monkey, and rat cerebral cortex receptor (
58
kDa) (23) and is less than that reported for the rat
pituitary and human myometrium (24). The difference in
molecular mass of CRH receptors is thought to be due mainly to the
extent of glycosylation or to the expression of different mRNAs. In
addition, the detected OX2R protein has a molecular mass of about 38
kDa. However, an additional product was detected at an apparent
molecular mass of 46 kDa, raising the possibility of posttranslational
modification of the receptor.
Previous studies have suggested a unique role for CRH in regulating fetal adrenal function via coupling to phospholipase C and induction of P450 C17 and DHEAS (8, 25). Treatment of human fetal adrenal cells with CRH induces inositol phosphate accumulation, but not cAMP production (25), whereas orexins induced cAMP production in rat adrenocortical cells in a dose-dependent manner (17).
Our results indicate that both CRH and orexin receptors in fetal adrenals can interact with multiple G proteins. Treatment with CRH increased GTP-AA labeling of Go and, to a lesser degree, Gs, but not Gi or Gq. The fact that the receptor is weakly coupled to Gs may explain the observation that no cAMP was produced (25). Alternatively, coupling of the receptor with the PTX-insensitive (26) Gz inhibitory protein (unpublished observations) may also account for low levels of cAMP production, as Gz can replace Gi in mediating inhibition of cAMP accumulation, but not in the stimulation of phospholipase C (27, 28). Our finding that the CRH-R did not activate Gq is of interest and suggests a novel role for Go, since in Xenopus oocytes Go is specifically capable of coupling to muscarinic receptors and directly stimulating the inositol triphosphate pathway via activation of phospholipase C (29).
The exact second messenger mechanisms by which OX2R can exert its actions have not been fully elucidated. Initial reports indicate that both orexin A and B evoke a dose-dependent increase in intracellular calcium (16), whereas in rat adrenocortical cells orexins appear to activate the adenylate cyclase/PKA-dependent signaling pathway (17).
In the present study we report for first time that OX2R can couple to two G proteins in human fetal adrenals when challenged with orexin A. Treatment with orexin A increased the labeling of Gs and Gi in fetal adrenal membranes. The physiological significance of this differential coupling remains to be elucidated.
This is the first time that conclusive evidence is given for the presence of OX2R in human fetal adrenals. In dispersed rat zona fasciculata-reticularis cells, both orexin A and orexin B can induce corticosterone production (17). Our data are in agreement with a recent study in which it was demonstrated that orexins stimulate glucocorticoid secretion from adult human adrenocortical cells (30). Moreover, CRH has been shown to exert similar effects, stimulating DHEAS secretion (8) and cortisol production by cultured fetal zone and neocortical zone cells (31). In addition, expression of CRH and its receptors has been demonstrated in cortical and chromaffin cells in human adult adrenals (32). However, the morphological and functional differentiation of the fetal adrenal gland varies, with catecholamines being produced and secreted from the late second trimester onwards (33). Moreover, in a recent developmental study of fetal adrenals, the average volume of medullary cells increased between 24–39 wk, indicating substantial tissue differentiation at the latest stages of intrauterine life (34). In our study paraffin-embedded fetal adrenals from very early second trimester were used, and therefore, we were unable to distinguish any specific binding of fluo-CRH to any neuronal elements at this particular stage of development.
We hypothesize, therefore, that the presence of the OX2R in human fetal adrenals could provide a link between orexins and steroidogenesis in the human fetus. We suggest that orexins, acting synergistically with CRH, can play a novel role in the human fetus, maintaining fetal nutrition and maturation of essential organ systems via adrenal steroidogenesis. Moreover, in fetuses, orexin may play a key role in development by influencing its feeding behavior and nutritional status in preparation of the fetus for extrauterine life. This may have implications in the link between fetal nutrition and adult diseases.
In summary, our findings strongly suggest that OX2R, orexin A,
CRH-R1, and CRH-R2 are present in human fetal adrenals. The
concept that both peptides acting via their receptors in the human
fetal adrenal play a role in steroidogenesis and energy balance is
attractive.
Acknowledgments
Footnotes
This work was supported by the Research and Development Department of Walsgrave Hospital National Health Service Trust and NIH Grant H008478 (to R.B.J.).
1 E.K. and H.S.R. should be considered first coauthors. 
Abbreviations: CRH-R1, CRH receptor type 1; CRH-R2, CRH receptor type 2; DHEAS, dehydroepiandrosterone sulfate; FISH, fluorescent in situ hybridization; GTP-AA, GTP-azidoanilide; OX1R, orexin type 1 receptor; OX2R, orexin type 2 receptor.
Received November 22, 2000.
Accepted May 10, 2001.
References
receptor. Mol Endocrinol 12:1077–1085 and the
CRH-C variant receptor. J Clin Endocrinol Metab 83:1376–1379-hydroxylase/17,20-lyase in human fetal adrenal cells via protein
kinase C. J Clin Endocrinol Metab 84:3732–3738 subunit Gz
couples neurotransmitter receptors to ion channels in sympathetic
neurons. Neuron 21:1201–1212[CrossRef][Medline]
This article has been cited by other articles:
 |
|
 |
|
  J. Wenzel, N. Grabinski, C. A. Knopp, A. Dendorfer, M. Ramanjaneya, H. S. Randeva, M. Ehrhart-Bornstein, P. Dominiak, and O. Johren Hypocretin/orexin increases the expression of steroidogenic enzymes in human adrenocortical NCI H295R cells Am J Physiol Regulatory Integrative Comp Physiol, November 1, 2009; 297(5): R1601 - R1609. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Ramanjaneya, A. C Conner, J. Chen, P. Kumar, J. E P Brown, O. Johren, H. Lehnert, P. R Stanfield, and H. S Randeva Orexin-stimulated MAP kinase cascades are activated through multiple G-protein signalling pathways in human H295R adrenocortical cells: diverse roles for orexins A and B J. Endocrinol., August 1, 2009; 202(2): 249 - 261. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Ramanjaneya, A. C. Conner, J. Chen, P. R. Stanfield, and H. S. Randeva Orexins Stimulate Steroidogenic Acute Regulatory Protein Expression through Multiple Signaling Pathways in Human Adrenal H295R Cells Endocrinology, August 1, 2008; 149(8): 4106 - 4115. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 P. Silveyra, V. Lux-Lantos, and C. Libertun Both orexin receptors are expressed in rat ovaries and fluctuate with the estrous cycle: effects of orexin receptor antagonists on gonadotropins and ovulation Am J Physiol Endocrinol Metab, October 1, 2007; 293(4): E977 - E985. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. Markovic, N. Papadopoulou, T. Teli, H. Randeva, M. A. Levine, E. W. Hillhouse, and D. K. Grammatopoulos Differential Responses of Corticotropin-Releasing Hormone Receptor Type 1 Variants to Protein Kinase C Phosphorylation J. Pharmacol. Exp. Ther., December 1, 2006; 319(3): 1032 - 1042. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. Voisin, A. E. Firar, V. Avondo, and M. Laburthe Orexin-Induced Apoptosis: The Key Role of the Seven-Transmembrane Domain Orexin Type 2 Receptor Endocrinology, October 1, 2006; 147(10): 4977 - 4984. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 E. W. Hillhouse and D. K. Grammatopoulos The Molecular Mechanisms Underlying the Regulation of the Biological Activity of Corticotropin-Releasing Hormone Receptors: Implications for Physiology and Pathophysiology Endocr. Rev., May 1, 2006; 27(3): 260 - 286. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R. Spinazzi, P. G. Andreis, G. P. Rossi, and G. G. Nussdorfer Orexins in the regulation of the hypothalamic-pituitary-adrenal axis. Pharmacol. Rev., March 1, 2006; 58(1): 46 - 57. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R. Sirianni, B. A. Mayhew, B. R. Carr, C. R. Parker Jr., and W. E. Rainey Corticotropin-Releasing Hormone (CRH) and Urocortin Act through Type 1 CRH Receptors to Stimulate Dehydroepiandrosterone Sulfate Production in Human Fetal Adrenal Cells J. Clin. Endocrinol. Metab., September 1, 2005; 90(9): 5393 - 5400. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. Spinazzi, M. Rucinski, G. Neri, L. K. Malendowicz, and G. G. Nussdorfer Preproorexin and Orexin Receptors Are Expressed in Cortisol-Secreting Adrenocortical Adenomas, and Orexins Stimulate in Vitro Cortisol Secretion and Growth of Tumor Cells J. Clin. Endocrinol. Metab., June 1, 2005; 90(6): 3544 - 3549. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. Karteris, R. J. Machado, J. Chen, S. Zervou, E. W. Hillhouse, and H. S. Randeva Food deprivation differentially modulates orexin receptor expression and signaling in rat hypothalamus and adrenal cortex Am J Physiol Endocrinol Metab, June 1, 2005; 288(6): E1089 - E1100. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R Gitau, D Adams, N M Fisk, and V Glover Fetal plasma testosterone correlates positively with cortisol Arch. Dis. Child. Fetal Neonatal Ed., March 1, 2005; 90(2): F166 - F169. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. Chen and H. S. Randeva Genomic Organization of Mouse Orexin Receptors: Characterization of Two Novel Tissue-Specific Splice Variants Mol. Endocrinol., November 1, 2004; 18(11): 2790 - 2804. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. Karteris, E. W. Hillhouse, and D. Grammatopoulos Urocortin II Is Expressed in Human Pregnant Myometrial Cells and Regulates Myosin Light Chain Phosphorylation: Potential Role of the Type-2 Corticotropin-Releasing Hormone Receptor in the Control of Myometrial Contractility Endocrinology, February 1, 2004; 145(2): 890 - 900. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. P. Kukkonen, T. Holmqvist, S. Ammoun, and K. E. O. Akerman Functions of the orexinergic/hypocretinergic system Am J Physiol Cell Physiol, December 1, 2002; 283(6): C1567 - C1591. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. S. Randeva, E. Karteris, D. Grammatopoulos, and E. W. Hillhouse Expression of Orexin-A and Functional Orexin Type 2 Receptors in the Human Adult Adrenals: Implications for Adrenal Function and Energy Homeostasis J. Clin. Endocrinol. Metab., October 1, 2001; 86(10): 4808 - 4813. [Abstract] [Full Text] [PDF]
|
|
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Endocrinology | Endocrine Reviews | J. Clin. End. & Metab. |
| Molecular Endocrinology | Recent Prog. Horm. Res. | All Endocrine Journals |
