| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
Original Studies |
Department of Internal Medicine III, University of Leipzig, 04103 Leipzig; Medical Faculty Carl Gustav Carus TU Dresden (M.B.), Dresden; and Diabetes Research Institute, University of Duesseldorf (W.A.S.), Duesseldorf, Germany; the Department of Pathology, National Cancer Institute (J.G.), and the Developmental Endocrinology Branch, National Institute of Child Health and Human Development (G.P.C., S.R.B.) National Institutes of Health, Bethesda, Maryland 20892
Address all correspondence and requests for reprints to: Dr. A. Glasow, Medizinische Klinik und Poliklinik III, University of Leipzig, Philipp-Rosenthal Strasse 27, 04103 Leipzig, Germany. E-mail: ges90apg{at}studserv.uni-leipzig.de
 |
Abstract |
|---|
 Top Abstract IntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
In conclusion, this is the first report identifying functional leptin receptor in human adrenal tissue and showing a differential action of leptin on human adrenocortical and chromaffin hormone production. This peripheral action of leptin on the adrenal gland provides an additional important link between the human stress response and body weight regulation.
|
Introduction |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
The adrenal gland contains the steroid-producing cortex and the catecholamine-producing medulla under a common capsule. Cortex and medulla influence each other’s secretory activity in a paracrine fashion (26, 27). Thus, glucocorticoids stimulate the expression of catecholamine enzymes, whereas products of the medulla stimulate steroidogenesis (28, 29, 30, 31). It is possible that leptin influences this interaction directly through specific receptors similar to these isolated in the central nervous system (CNS) (32, 33, 34). Recent studies demonstrated important peripheral actions of leptin in humans, including modulation of insulin action on liver cells (35), suppression of insulin secretion by pancreatic ß-cells (36), stimulation of hematopoietic stem cells (43, 44, 45, 46), and inhibition of estradiol secretion by the ovaries (37). Here, we performed the first comprehensive study on the potential direct role of leptin in human adrenal function.
We analyzed the expression and distribution of leptin receptors in normal human adrenal tissue. As cortical and chromaffin adrenal tissues are markedly interwoven in humans, we used the novel technique of laser capture microdissection (LCM) to select, under direct microscopic visualization, appropriate cell populations (38, 39). We achieved a clear separation of cortical and chromaffin cells for messenger ribonucleic acid (mRNA) expression studies and examined the effect of leptin on basal and ACTH-stimulated steroid secretion by normal primary human adrenal cell cultures. In addition, we examined the effect of leptin on basal catecholamine release from cultured chromaffin cells. As leptin was previously found in peripheral tissues other than fat, such as the human placenta and rat skeletal muscle (40, 41, 42), we also investigated the expression of leptin in the adrenal glands.
|
Materials and Methods |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
Unless otherwise indicated, all reagents were purchased from Sigma Chemical Co.
Tissue processing
Eight normal human adrenals from patients who had been unilaterally nephrectomized for renal carcinoma were analyzed in this study. Immediately after surgery, the adrenals were transferred to prechilled phosphate-buffered saline and kept on ice until further treatment for RT-PCR, Western blotting, and in vitro studies. The age of the donors varied between 32–75 yr. The study was approved by the ethical committee of the University of Leipzig.
Immunohistochemical procedures
Immunostaining was performed by the labeled streptavidin-biotin-technique (Dako Corp., Hamburg, Germany). Eight formalin-fixed normal adrenals were sectioned, deparaffinized, and unmasked by heat treatment in sodium citrate buffer (pH 6, 10 mM) at 95C for 15 min before blocking endogenous peroxidase with 0.3% H2O2 for 15 min. Following the manufacturer’s protocol, the sections were preincubated with 2% normal swine serum and exposed for 30 min to the 1:50 dilution of the polyclonal goat antihuman leptin receptor antibody (Ob-R; C-20, Santa Cruz Biotechnology, Inc., Santa Cruz, CA). The antibody is raised against a peptide corresponding to amino acids 1146–1165 mapping the carboxyl-terminus of the full-length Ob-R. As a negative control the human Ob-R antibody was replaced by goat IgG (Dianova-Immunotech, Hamburg, Germany), and no nonspecific staining was observed. After incubation with biotinylated link antibody for 15 min and peroxidase-labeled streptavidin for 15 min, visualization was achieved by immersion of the sections for 10 min in 3-amino-9-ethyl-carbazole (Dianova). Slides were counterstained with hematoxylin for 1 min, rinsed for 10 min in water, and mounted with glycerin gelatin. Hypothalamus was used as a positive tissue control (data not shown).
Immunostaining for leptin was performed on five adrenals in the same way using a rabbit antihuman leptin antibody (Ob; Y-20 RDI Research Diagnostics, Inc., Flanders, NJ) suitable for Western blotting and immunohistochemistry. Negative controls with nonimmune rabbit serum were performed and showed no nonspecific staining. Formalin-fixed, paraffin-embedded human fat tissue was successfully stained as a positive tissue control.
Western blot analysis
To isolate protein from adrenal and fat, 100 mg tissue were disrupted on ice by grinding in a sintered glass Dounce-type homogenizer (Potter S, B. Braun, Melsungen, Germany) in 0.1 mol/L sucrose and subsequently homogenized on ice twice for 5 s each time (20 kHz) using an Ultrasonic Processor (B. Braun). After centrifugation, the protein concentration in the supernatant was determined by the Bradford protein assay. Between 75–112 µg protein from each sample were mixed with 0.2 vol 5 x SDS-mercaptoethanol-glycerol solution (43), boiled for 5 min, and separated in a SDS-15% polyacrylamide gel electrophoresis at 30 mA for 1 h. The samples were electroblotted (Bio-Rad Laboratories, Inc., Munich, Germany) onto nitrocellulose membranes at 15 V (Bio-Rad Laboratories, Inc.) for 1.5 h, processed, and incubated with Tween-TBS containing 1:100 rabbit antihuman leptin antibody (Ob; Y-20 RDI Research Diagnostics). They were analyzed by chemiluminescence according to a standard protocol (ECL, Amersham, Germany). Low range marker (Bio-Rad Laboratories, Inc.) was used to calculate protein weight after Ponceau red staining.
Laser capture microdissection (LCM)
Frozen tissue sections were fixed in 70% alcohol and stained in hematoxylin and eosin. Sections were dehydrated in graded alcohols and then in xylene and were air-dried for 5 min before LCM. The optically transparent thin film caps were placed on top of tissue sections, and the tissue-film sandwich was viewed in an inverted microscope (model CK2, Olympus Corp., Tokyo, Japan). Using a photodiode laser beam (Arcturus, Mountain View, CA), medullary and cortical cells were separated by melting film and target tissue and removing both from the surrounding area. Then total RNA was extracted from cells adhered to the film cap according to the RNA microisolation protocol (Stratagene, La Jolla, CA).
RNA isolation and complementary DNA (cDNA) synthesis
Total RNA was isolated from 2 x 106 cultured cells or 100 mg adrenal tissue by a silica gel-based membrane method using the RNeasy kit (Quiagen, Hilden, Germany) according to the manufacturer’s protocol. RNA content and quality were determined photometrically. The RNA was digested with ribonuclease-free deoxyribonuclease A (Boehringer Mannheim, Mannheim, Germany) and 1 U/µg RNA in 20 mmol/L Tris-HCl, pH 8.0, and 2.5 mmol/L MgCl for 10 min at 27 C. The reaction was stopped by incubation at 65 C for 10 min and addition of 5% (vol/vol) ethylenediamine tetraacetate (EDTA; 20 mmol/L). To control complete digestion of DNA, a glyceraldehyde-3-phosphate dehydrogenase GAPDH PCR was performed using RNA as template. Five micrograms of RNA were taken to synthesize cDNA using the cDNA single-strand synthesis kit with oligo(deoxythymidine) primers (Pharmacia Biotech, Freiburg, Germany). The quality of the templates was confirmed by GAPDH PCR (44).
PCR experiments
PCR was performed in a GeneAmp 9600 thermal cycler (Perkin Elmer, Uberlingen, Germany) using 5'Cy5-labeled, intron-spanning
primer pairs for the full-length human leptin receptor (Ob-R), for the
short isoforms (Ob-R219.1-Ob-R219.3), and for human leptin (Table 1
). The cDNA was amplified in 25 µL
containing 1 x PCR buffer with 1.5 mmol/L MgCl, 200 µmol/L
deoxy-NTPs, 10 pmol each of forward and reverse primers, and 0.5 U
Expand high fidelity polymerase (Boehringer Mannheim). To amplify Ob-R
mRNA and leptin mRNA, an initial denaturation step at 94 C for 2 min
was followed by 36/40 cycles: denaturation at 94 C for 30 s,
annealing at primer-specific temperature for 30 s (Table 1), and
elongation 72 C for 40 s. The final elongation step was prolonged
to 7 min. In all PCR experiments, amplification in the absence of cDNA
was performed as a negative control. The human hepatocellular carcinoma
cell line, HepG2, and adrenal peripheral adipose tissue cDNA were used
as a positive control for Ob-R and Ob mRNA (45, 46, 47, 48).
|
Cell culture experiments
Normal human adrenals (n = 6) were dissected mechanically, digested enzymatically, and cultured as previously described (49). In addition, erythrocytes were removed before seeding the cells by treatment with erythrocyte lysis buffer (0.15 mol/L NH4Cl, 0.1 mmol/L Na2EDTA, and 12 mmol/L NaHCO3) at 37 C for 3 min. The lysis was stopped by adding ice-cold phosphate-buffered saline and subsequent centrifugation.
Stimulation experiments
Human adrenal primary cells were cultured in 24-well dishes (150,000 cells/well) for 3 days. After washing with serum-free medium containing ascorbic acid (10-7 mol/L), transferrin (0.001% wt/vol), and bacitracin (0.01%, wt/vol), cells were incubated in serum-free medium containing human recombinant leptin at concentrations ranging from 0.01–1000 ng/mL (TEBU, Frankfurt, Germany) with or without 10-10 mol/L ACTH (Synacten, Ciba-Geigy, Wehr, Germany). Bacitracin was used as a protease inhibitor to protect leptin from proteolytic degradation. The concentration of leptin in the presence of bacitracin was measured at the beginning and after 24 h of stimulation. No loss of leptin was detected.
For catecholamine measurements, cells were incubated in 250 µL medium for 15, 30, and 90 min with 100 ng/mL leptin. Supernatants of four wells were pooled, 10% (vol/vol) preservative buffer (0.027 mmol/L Na2EDTA and 0.57 mmol/L ascorbic acid) was added, and samples were kept at -80 C until extraction and measurement.
Hormone measurements
Hormone concentrations in the incubation medium were measured by RIA, using the following kits: cortisol RIA (Biermann, Bad Nauheim, Germany; sensitivity, 5.5 nmol/L; cross-reactivity: cortisol, 100%; prednisolone, 76%; 11-deoxycortisol, 11.4%; prednisone, 2.3%; other steroids, <1%; intra- and interassay variations, 5.1% and 6.4%, respectively); Active dehydroepiandrosterone (DHEA; Diagnostic Systems Laboratories, Webster, TX; sensitivity, 0.07 ng/mL; cross-reactivity: DHEA, 100%; other steroids, <0.88%; intra- and interassay variations, 10.6% and 10.2%, respectively); leptin RIA (DRG Instruments GmbH, Marburg, Germany; sensitivity, 0.5 ng/mL; intra- and interassay variations, 8.3% and 6.2%); and aldosterone RIA (Biermann; sensitivity, 16 pg/mL; cross-reactivity: aldosterone, 100%; other steroids, <0.003%; intra- and interassay variations, 5% and 10.4%). Norepinephrine and epinephrine were measured by high performance liquid chromatography according to the manufacturer’s protocol for plasma levels (Chromosystems, Munich, Germany; sensitivity, 10 pg/mL; intra- and interassay variations, 5.6% and 5.9%). Catecholamines were detected with the Waters 460 electrochemical detector (Waters Associates, Milford, MA), and the evaluation of the chromatogram was performed using Millenium 2000 software (Millipore Corp., Milford, MA).
Northern blot analysis
Messenger RNA (mRNA) was isolated from 2 x 106 cortical cells/experiment using a Dynabeads mRNA direct kit (Dynal, Oslo, Norway). Isolated mRNA was fractionated by electrophoresis through a 1.2% agarose gel containing 0.61 mol/L formaldehyde under denaturing conditions and transferred to uncharged nylon membranes (Qiagen).
Human cytochrome P45017
cDNA (courtesy of M. R.
Waterman, Nashville, TN) was labeled with digoxigenin (Dig)-UTP using
the Dig-RNA labeling kit (SP6/T7) from Boehringer Mannheim by in
vitro transcription. The human Dig-labeled GAPDH RNA probe was
provided by Dr. U. Anderegg, Department of Dermatology, University of
Leipzig (Leipzig, Germany). Hybridization and chemiluminescence
detection were performed as previously described (49). Hybridization
signals in the blots were normalized with GAPDH and analyzed
quantitatively by densitometric scanning. Sense probes were used to
confirm the specificity of the antisense cytochrome
P45017 RNA probe.
Proliferation and viability assay
We studied the effect of leptin on the viability of adrenal primary cell culture by the WST-1 assay (Boehringer Mannheim). Cells were cultured on 24-well plates for 3 days. On day 4, cells were incubated with different leptin concentrations in the stimulation medium for 24 h, as described above. After this period, 10% (vol/vol) WST-1 reagent was added. After 50 min, absorbance of the samples was measured against a background control (stimulation medium containing 10% WST-1) at 450 nm following the manufacturer’s protocol. To correlate absorbance with cell number, various numbers of cells (50,000–400,000) were employed.
Statistical analysis
Results are expressed as the mean ± SEM. Statistical significance was determined by ANOVA simple multifactorial analysis using the software package SPSS for Windows, version 6.0. Differences were considered significant at P < 0.05. All experiments for hormone measurements were repeated for a minimum of three different cell preparations (n) using quadruplicate determinations.
|
Results |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
As in human adrenal glands the two endocrine cell systems are
highly intermingled, we applied LCM to separate both tissues. Medullary
cells were transfered from the adrenal sections via an adhesive film
layer in RNA isolation buffer to produce cDNA exclusively from
chromaffin cells. After specific removal of medullary cells, only
cortical tissue remained on the slide (Fig. 1, A and B).
|
After laser dissection of adrenal tissue, the mRNA of the active
long form of the Ob-R could be detected in both adrenocortical and
adrenomedullary tissue (Fig. 2A). In
addition, the mRNA of the isoforms Ob-R 219.1–3, lacking a part of the
intracellular domain, were observed in normal human adrenal cell
cultures (HAC) and adrenal tissues (Fig. 2, B–D). Amplification with
the HepG2 cell line and human adipose tissue cDNA template served as
positive controls (45, 47, 48).
|
The full-length Ob-R was detected by immunostaining in the cortex
of normal human adrenals (Fig. 3A). Dense
and even labeling was demonstrated in all three zones, with no
significant differences in the intensity of staining (Fig. 3, B and C).
In contrast, there was only a very weak signal for the Ob-R in the
adrenal medulla (m). However, the cortical cell islets within the
medulla were strongly stained for the Ob-R, demonstrating the high
degree of intermingling between the two endocrine tissues (Fig. 3, A
and C). A similar pattern of labeling, independent from sex and age,
was found in each of the eight adrenals.
|
By RT-PCR, no leptin mRNA was detectable in three different
adrenal cell cultures. In human adrenal tissue only a minimal amount of
leptin mRNA was detected in one of four adrenals studied, probably
because of contaminating periadrenal fat tissue. In human adipose
tissue, used as a positive control (46), we could show leptin mRNA
expression resulting in a 366-bp product (Fig. 4).
|
Effect of leptin on hormone secretion
Leptin led to a dose-dependent decrease in ACTH-stimulated
adrenocortical steroid secretion in HAC in a range of 0.01–1000 ng/mL.
The ACTH-stimulated aldosterone secretion was decreased by 29.1 ±
5.1% (P < 0.001), whereas cortisol and
DHEA secretion decreased by 16.0 ± 2.7%
(P < 0.001) and 15.0 ± 4.3% (P
< 0.01; n = 3; mean ± SEM) after exposure to
leptin (1000 ng/mL; Fig. 5, A–C). The
basal levels of steroid hormone concentration (cortisol, 9.40 ±
0.58 nmol/mL; aldosterone, 92.6 ± 4.02 pmol/L; DHEA,
1.28 ± 0.26 ng/mL) remained unchanged.
|
Northern analysis was performed to determine whether the inhibiting
effect of leptin on steroid hormone synthesis was mediated by its
action on the expression of mRNA of steroid enzymes (Fig. 5
, D and E).
Treatment of human adrenal primary cell cultures with ACTH
(10-9 mol/L) increased cytochrome P45017
mRNA expression to 169 ± 4.3% (n = 2) of the basal level.
Coincubation with 100 ng/mL leptin for 24 h led to a significant
decrease of 50% in ACTH-stimulated mRNA expression. Hybridization with
the cytochrome P450 side-chain cleavage DNA probe, however,
demonstrated no significant effect of leptin on cytochrome P450
side-chain cleavage mRNA expression (data not shown).
Cell viability and proliferation experiments
The proliferation assay (WST-1 test) proved that leptin had no influence on the viability and proliferation rate of adrenal cells in primary culture. After incubation with 100 and 1000 ng/mL leptin, basal levels of adsorbance (0.428 ± 0.026 ng/mL; n = 2) did not significantly change.
|
Discussion |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
The leptin receptor occurs in a long form, predominantly expressed in the hypothalamus (32), and as several other shorter isoforms. Three membrane-bound isoforms, Ob-R 219.1–3, were characterized in human fetal liver (52, 53). Using the new technique of laser microdissection we were able to separate medullary and cortical adrenal cells. By RT-PCR we have demonstrated the mRNA expression of the long form Ob-R in both endocrine tissues. Furthermore, all of the Ob-R 219.1–3 isoforms were expressed in the human adrenal. The physiological meaning of the Ob-R isoforms is not exactly known. Interestingly, all of the receptor isoforms contain the box 1 motif, which is critical for Jak2 binding and intracellular signaling (53, 54) but lack the box 3 motif, which mediates signal transduction via STAT1 (signal transducer and activator of transcription) and STAT3 (55). It has been shown that the short receptor isoforms transduce some, but not all, genes affected by activation of the long form receptor and may modulate the function of the full-length Ob-R by competitive effects (53).
The Ob-R protein expression was detected in all zones of the adrenal
cortex, suggesting a potential role for leptin in several adrenal
cortical functions. The low density of Ob-R protein in the adrenal
medulla implies that leptin has no or a minor direct effect on the
catecholamine-producing cells. Several pieces of evidence suggest that
the mild, but significant, inhibition of adrenal steroidogenesis by
leptin is of physiological relevance. Incubation of cortical cells with
leptin led to a dose-dependent reduction of ACTH-stimulated steroid
release. The concentrations of leptin used in the stimulation
experiments are within the in vivo range of this hormone (8, 56). A strong inhibitory effect of leptin on adrenal steroid hormone
release, however, required higher concentrations than those in plasma.
These concentrations were similar to those inhibiting FSH-stimulated
estradiol release from human ovary cells (57) and correspond to those
of other established inhibitors of human adrenocortical
steroidogenesis, such as atrial natriuretic factor, dopamine, and
transforming growth factor-ß1 (58, 59, 60). Of note is that the adrenal
gland is naturally embedded in adipose tissue, potentially leading to
higher local concentrations of leptin. In addition, endogenously
produced leptin undergoes posttranslational modification and can be
more potent than recombinant leptin (61, 62). Finally, the fact that
leptin led to a 50% decrease in ACTH-stimulated cytochrome P450 mRNA
expression provides further evidence for the biological importance of
this effect on adrenal steroidogenesis. This effect was most pronounced
on the expression of 17-hydroxylase, which is a major regulatory
enzyme that responds rapidly to ACTH (63). Indirect effects of leptin
on cell metabolism and proliferation were excluded by viability and
proliferation analyses using the WST-1 test.
In both rats and humans, there is a strict reciprocal diurnal relation between leptin and cortisol levels (64, 65). In fact, leptin may explain this relation by involving both CNS and peripheral mechanisms that influence cortical secretion (27, 28). To date, it is not fully understood how leptin regulates the functioning of the HPA axis at the level of hypothalamus. Recent data in rodents suggest that leptin inhibits stress-induced activation of CRH neurons, whereas it may stimulate CRH neurons that mediate the anorectic effects of CRH (6, 13, 25, 66, 67). A peripheral inhibition of adrenal glucocorticoid production and a chronic inhibition of steroid enzyme expression are in accordance with these findings and appear to be a teleologically appropriate property for an adipostatic hormone. Stromal cells in human adipose tissue develop the characteristic feature of adipocytes after stimulation with glucocorticoids (20, 68). Glucocorticoids produce the biochemical features of visceral fat syndrome, including obesity, insulin resistance, dyslipidemia, and hypertension (10, 12).
The decrease in human steroid hormone secretion by leptin incubation could be part of a feedback regulation similar to the mechanism previously described for insulin regulation (69, 70). Thus, increased leptin secretion, as observed in obesity, diabetes type II, and Cushing’s syndrome (21, 71, 72), may constitute a counterregulatory attempt to limit glucocorticoid-induced hyperphagia and weight gain.
Interestingly, the most pronounced receptor-mediated inhibitory effect of leptin was found on aldosterone biosynthesis. A decrease in mineralocorticoid secretion leads to a fall in blood pressure. An acute leptin infusion in the rat results in increased SS/AM system activity, but does not alter arterial pressure or heart rate, suggesting other actions of leptin that oppose sympathetically mediated vasoconstriction (22). Chronic leptin infusion, on the other hand, clearly increased arterial pressure in rats. At the same time the plasma concentrations of aldosterone and corticosterone tended to decrease, whereas renin levels were unchanged (73). Therefore, our data may indicate a counterregulatory function of leptin in hypertension through inhibition of aldosterone secretion by the adrenal gland. In accordance with these findings, it was shown that infusion of leptin caused natriuresis and diuresis (74). Suppression of adrenal aldosterone production may have other important clinical implications. In addition to its role in obesity-related hypertension, the hyperleptinemia that occurs in critically ill patients (75) may contribute to the primary hypoaldosteronism that is found in a substantial percentage of these patients (76).
Although leptin activates the sympathetic nervous system via CNS action (22, 77), it was not known whether this hormone had a direct effect on human adrenal catecholamine production. Immunohistochemical studies in rats demonstrated that the short form of the leptin receptor was abundant in the medulla, particularly on epinephrine-secreting cells (78). In mice, the long form of the Ob-R was detected by RT-PCR in the adrenal medulla (79). In human adrenal medulla, however, there was only a weak staining of the Ob receptor protein. As the human adrenal medulla is frequently speckled with cortical cells, a clear separation of chromaffin cells from cortical tissue was achieved by LCM, providing isolation of RNA for RT-PCR studies exclusively from chromaffin cells. Applying this method and PCR, we detected the expression of the mRNA for the long form of the leptin receptor on adrenomedullary cells.
Even though leptin increases the activity of central sympathetic neurons, peripheral sympathetic outflow, and norepinephrine turnover in brown adipose tissue (80), we found no significant direct effect of this hormone on adrenomedullary catecholamine release. This is in line with the weak expression of leptin receptor protein in the medulla and possibly part of the known dissociation between the systemic sympathetic nervous and adrenomedullary system (81).
Finally, leptin is ancestrally related to cytokines, and the leptin receptor is a member of the class I cytokine receptor superfamily that includes the gp130 subunit of the interleukin-6 receptor (32). Interleukin-6 receptor and other cytokines, such interleukin-1 and tumor necrosis factor (82, 83, 84), and major histocompatibility complex class II molecules are expressed in the inner adrenocortical zones, which also show a high density of resident macrophages (85). As leptin has been demonstrated to regulate immune function, including lymphopoiesis and phagocytic capacity of macrophages, it will be of interest to define its role in immune-adrenal interactions (27).
Paracrine or autocrine effects of leptin are not be suspected to be involved in the regulation of steroid or catecholamine release within the adrenals, as we detected no signal for leptin by Western analysis or immunohistochemical staining. The small amount of leptin mRNA in one of the four studied adrenals may be due to residual periadrenal fat tissue and does not seem to be of physiological relevance.
In conclusion, 1) we detected all forms of Ob receptors in the normal human adrenal cortex; 2) leptin itself was not expressed in human adrenal; and 3) leptin had a differential effect on hormonal functions of the adrenal. Although the adrenomedullary catecholamine secretion was not affected by this hormone, diminishing a potential direct role of leptin in energy metabolism through epinephrine regulation, it inhibited ACTH-stimulated steroid release by all three zones of the adrenal cortex. This adipo-adrenal interaction mediated by leptin may further underscore the close link of metabolism and stress regulation in humans.
|
Acknowledgments |
|---|
|
Footnotes |
|---|
Received May 8, 1998.
Revised August 6, 1998.
Accepted August 11, 1998.
|
References |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
messenger ribonucleic acid:
evidence for paracrine control of adrenal function. J Clin
Endocrinol Metab. 81:807–813.[Abstract]
This article has been cited by other articles:
 |
|
 |
|
  S. Aquila, V. Rago, C. Guido, I. Casaburi, S. Zupo, and A. Carpino Leptin and leptin receptor in pig spermatozoa: evidence of their involvement in sperm capacitation and survival Reproduction, July 1, 2008; 136(1): 23 - 32. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 I. H. Trevenzoli, M. M. R. Valle, F. B. Machado, R. M. G. Garcia, M. C. F. Passos, P. C. Lisboa, and E. G. Moura Neonatal hyperleptinaemia programmes adrenal medullary function in adult rats: effects on cardiovascular parameters J. Physiol., April 15, 2007; 580(2): 629 - 637. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S-N Wang, S-C Chuang, Y-T Yeh, S-F Yang, C-Y Chai, W-T Chen, K-K Kuo, J-S Chen, and K-T Lee Potential prognostic value of leptin receptor in hepatocellular carcinoma J. Clin. Pathol., December 1, 2006; 59(12): 1267 - 1271. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 H.-T. Hsu, Y.-C. Chang, Y.-N. Chiu, C.-L. Liu, K.-J. Chang, and I.-C. Guo Leptin Interferes with Adrenocorticotropin/3',5'-Cyclic Adenosine Monophosphate (cAMP) Signaling, Possibly through a Janus Kinase 2-Phosphatidylinositol 3-Kinase/Akt-Phosphodiesterase 3-cAMP Pathway, to Down-Regulate Cholesterol Side-Chain Cleavage Cytochrome P450 Enzyme in Human Adrenocortical NCI-H295 Cell Line J. Clin. Endocrinol. Metab., July 1, 2006; 91(7): 2761 - 2769. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 P. H. Jethwa, K. L. Smith, C. J. Small, C. R. Abbott, S. J. Darch, K. G. Murphy, A. Seth, N. M. Semjonous, S. R. Patel, J. F. Todd, et al. Neuromedin U Partially Mediates Leptin-Induced Hypothalamo-Pituitary Adrenal (HPA) Stimulation and Has a Physiological Role in the Regulation of the HPA Axis in the Rat Endocrinology, June 1, 2006; 147(6): 2886 - 2892. [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]
|
|
|
|
 |
|
 M. Misra, K. K. Miller, K. Kuo, K. Griffin, V. Stewart, E. Hunter, D. B. Herzog, and A. Klibanski Secretory dynamics of leptin in adolescent girls with anorexia nervosa and healthy adolescents Am J Physiol Endocrinol Metab, September 1, 2005; 289(3): E373 - E381. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. Mazzocchi, P. Rebuffat, A. Ziolkowska, G. P. Rossi, L. K. Malendowicz, and G. G. Nussdorfer G Protein Receptors 7 and 8 Are Expressed in Human Adrenocortical Cells, and Their Endogenous Ligands Neuropeptides B and W Enhance Cortisol Secretion by Activating Adenylate Cyclase- and Phospholipase C-Dependent Signaling Cascades J. Clin. Endocrinol. Metab., June 1, 2005; 90(6): 3466 - 3471. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 K. Yuan, T.-M. Hong, J. J. W. Chen, W. H. Tsai, and M. T. Lin Syndecan-1 up-regulated by ephrinB2/EphB4 plays dual roles in inflammatory angiogenesis Blood, August 15, 2004; 104(4): 1025 - 1033. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Misra, K. K. Miller, C. Almazan, K. Ramaswamy, A. Aggarwal, D. B. Herzog, G. Neubauer, J. Breu, and A. Klibanski Hormonal and Body Composition Predictors of Soluble Leptin Receptor, Leptin, and Free Leptin Index in Adolescent Girls with Anorexia Nervosa and Controls and Relation to Insulin Sensitivity J. Clin. Endocrinol. Metab., July 1, 2004; 89(7): 3486 - 3495. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Ishikawa, J. Kitayama, and H. Nagawa Enhanced Expression of Leptin and Leptin Receptor (OB-R) in Human Breast Cancer Clin. Cancer Res., July 1, 2004; 10(13): 4325 - 4331. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. Salzmann, M. Otis, H. Long, C. Roberge, N. Gallo-Payet, and C.-D. Walker Inhibition of Steroidogenic Response to Adrenocorticotropin by Leptin: Implications for the Adrenal Response to Maternal Separation in Neonatal Rats Endocrinology, April 1, 2004; 145(4): 1810 - 1822. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. Mazzocchi, L. K. Malendowicz, F. Aragona, R. Spinazzi, and G. G. Nussdorfer Cholecystokinin (CCK) Stimulates Aldosterone Secretion from Human Adrenocortical Cells via CCK2 Receptors Coupled to the Adenylate Cyclase/Protein Kinase A Signaling Cascade J. Clin. Endocrinol. Metab., March 1, 2004; 89(3): 1277 - 1284. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M C Henson, K F Swan, D E Edwards, G W Hoyle, J Purcell, and V D Castracane Leptin receptor expression in fetal lung increases in late gestation in the baboon: a model for human pregnancy Reproduction, January 1, 2004; 127(1): 87 - 94. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 X. Hu, S. C. Juneja, N. J. Maihle, and M. P. Cleary Leptin--A Growth Factor in Normal and Malignant Breast Cells and for Normal Mammary Gland Development J Natl Cancer Inst, November 20, 2002; 94(22): 1704 - 1711. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Weise, G. Eisenhofer, and D. P. Merke Pubertal and Gender-Related Changes in the Sympathoadrenal System in Healthy Children J. Clin. Endocrinol. Metab., November 1, 2002; 87(11): 5038 - 5043. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. Charmandari, M. Weise, S. R. Bornstein, G. Eisenhofer, M. F. Keil, G. P. Chrousos, and D. P. Merke Children with Classic Congenital Adrenal Hyperplasia Have Elevated Serum Leptin Concentrations and Insulin Resistance: Potential Clinical Implications J. Clin. Endocrinol. Metab., May 1, 2002; 87(5): 2114 - 2120. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. Loffler, G. Aust, U. Kohler, and K. Spanel-Borowski Evidence of leptin expression in normal and polycystic human ovaries Mol. Hum. Reprod., December 1, 2001; 7(12): 1143 - 1149. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Glasow, W. Kiess, U. Anderegg, A. Berthold, A. Bottner, and J. Kratzsch Expression of Leptin (Ob) and Leptin Receptor (Ob-R) in Human Fibroblasts: Regulation of Leptin Secretion by Insulin J. Clin. Endocrinol. Metab., September 1, 2001; 86(9): 4472 - 4479. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Glasow, L.-C. Horn, S. E. Taymans, C. A. Stratakis, P. A. Kelly, U. Kohler, J. Gillespie, B. K. Vonderhaar, and S. R. Bornstein Mutational Analysis of the PRL Receptor Gene in Human Breast Tumors with Differential PRL Receptor Protein Expression J. Clin. Endocrinol. Metab., August 1, 2001; 86(8): 3826 - 3832. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
N. Cherradi, A. M. Capponi, R. C. Gaillard, and F. P. Pralong Decreased Expression of Steroidogenic Acute Regulatory Protein: A Novel Mechanism Participating in the Leptin-Induced Inhibition of Glucocorticoid Biosynthesis Endocrinology, August 1, 2001; 142(8): 3302 - 3308. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Lacroix, N. N'Diaye, J. Tremblay, and P. Hamet Ectopic and Abnormal Hormone Receptors in Adrenal Cushing's Syndrome Endocr. Rev., February 1, 2001; 22(1): 75 - 110. [Abstract] [Full Text]
|
|
|
|
|
|
G. Mazzocchi, L. K. Malendowicz, L. Gottardo, F. Aragona, and G. G. Nussdorfer Orexin A Stimulates Cortisol Secretion from Human Adrenocortical Cells through Activation of the Adenylate Cyclase-Dependent Signaling Cascade J. Clin. Endocrinol. Metab., February 1, 2001; 86(2): 778 - 782. [Abstract] [Full Text]
|
|
|
|
|
|
K. Takekoshi, K. Ishii, Y. Kawakami, K. Isobe, T. Nanmoku, and T. Nakai Ca2+ Mobilization, Tyrosine Hydroxylase Activity, and Signaling Mechanisms in Cultured Porcine Adrenal Medullary Chromaffin Cells: Effects of Leptin Endocrinology, January 1, 2001; 142(1): 290 - 298. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. R. González, P. Caballero-Campo, M. Jasper, A. Mercader, L. Devoto, A. Pellicer, and C. Simon Leptin and Leptin Receptor Are Expressed in the Human Endometrium and Endometrial Leptin Secretion Is Regulated by the Human Blastocyst J. Clin. Endocrinol. Metab., December 1, 2000; 85(12): 4883 - 4888. [Abstract] [Full Text]
|
|
|
|
|
|
A. Bottner, A. Haidan, G. Eisenhofer, K. Kristensen, A. L. Castle, W. A. Scherbaum, H. Schneider, G. P. Chrousos, and S. R. Bornstein Increased Body Fat Mass and Suppression of Circulating Leptin Levels in Response to Hypersecretion of Epinephrine in Phenylethanolamine-N-Methyltransferase (PNMT)-Overexpressing Mice Endocrinology, November 1, 2000; 141(11): 4239 - 4246. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 P C Ng, C W K Lam, C H Lee, G W K Wong, T F Fok, E Wong, K C Ma, and I H S Chan Leptin and metabolic hormones in infants of diabetic mothers Arch. Dis. Child. Fetal Neonatal Ed., November 1, 2000; 83(3): 193F - 197. [Abstract] [Full Text]
|
|
|
|
|
|
M. Castellucci, R. De Matteis, A. Meisser, R. Cancello, V. Monsurro, D. Islami, R. Sarzani, D. Marzioni, S. Cinti, and P. Bischof Leptin modulates extracellular matrix molecules and metalloproteinases: possible implications for trophoblast invasion Mol. Hum. Reprod., October 1, 2000; 6(10): 951 - 958. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
F. Fend and M. Raffeld Laser capture microdissection in pathology J. Clin. Pathol., September 1, 2000; 53(9): 666 - 672. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. Alfer, F. Muller-Schottle, I. Classen-Linke, U. von Rango, L. Happel, K. Beier-Hellwig, W. Rath, and H. M. Beier The endometrium as a novel target for leptin: differences in fertility and subfertility Mol. Hum. Reprod., July 1, 2000; 6(7): 595 - 601. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Biason-Lauber, M. Zachmann, and E. J. Schoenle Effect of Leptin on CYP17 Enzymatic Activities in Human Adrenal Cells: New Insight in the Onset of Adrenarche Endocrinology, April 1, 2000; 141(4): 1446 - 1454. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S Curran, J A McKay, H L McLeod, and G I Murray Laser capture microscopy Mol. Pathol., April 1, 2000; 53(2): 64 - 68. [Abstract] [Full Text]
|
|
|
|
 |
|
 A. E. Green, J. S. O'neil, K. F. Swan, R. P. Bohm Jr., M. S. Ratterree, and M. C. Henson Leptin Receptor Transcripts Are Constitutively Expressed in Placenta and Adipose Tissue with Advancing Baboon Pregnancy Experimental Biology and Medicine, April 1, 2000; 223(4): 362 - 366. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. Jin, S. Zhang, B. G. Burguera, M. E. Couce, R. Y. Osamura, E. Kulig, and R. V. Lloyd Leptin and Leptin Receptor Expression in Rat and Mouse Pituitary Cells Endocrinology, January 1, 2000; 141(1): 333 - 339. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Caprio, A. M. Isidori, A. R. Carta, C. Moretti, M. L. Dufau, and A. Fabbri Expression of Functional Leptin Receptors in Rodent Leydig Cells Endocrinology, November 1, 1999; 140(11): 4939 - 4947. [Abstract] [Full Text]
|
|
|
|
|
|
F. P. Pralong, F. Gomez, L. Guillou, F. Mosimann, S. Franscella, and R. C. Gaillard Food-Dependent Cushing's Syndrome: Possible Involvement of Leptin in Cortisol Hypersecretion J. Clin. Endocrinol. Metab., October 1, 1999; 84(10): 3817 - 3822. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. Jin, B. G. Burguera, M. E. Couce, B. W. Scheithauer, J. Lamsan, N. L. Eberhardt, E. Kulig, and R. V. Lloyd Leptin and Leptin Receptor Expression in Normal and Neoplastic Human Pituitary: Evidence of a Regulatory Role for Leptin on Pituitary Cell Proliferation J. Clin. Endocrinol. Metab., August 1, 1999; 84(8): 2903 - 2911. [Abstract] [Full Text]
|
|
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| 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 |
