(Hypertension. 1997;30:1274-1278.)
© 1997 American Heart Association, Inc.
Articles |
Impaired Cortisol Binding to Glucocorticoid Receptors in Hypertensive Patients
From the Department of Medicine and Experimental Oncology, University of Turin, Italy (P.M., D.S., A.R., G.M., L.C., F.V.), and the Departments of Clinical Biochemistry (M.P.) and Medicine (C.J.K.), University of Edinburgh, UK.
Correspondence to Paolo Mulatero, MD, Cattedra Medicina Interna, Ospedale San Vito, Strada San Vito 34, 10133 Torino, Italy.
 |
Abstract |
|---|
 Top Abstract IntroductionMethodsResultsDiscussionReferences |
|---|
Abstract We compared glucocorticoid receptor binding characteristics and glucocorticoid responsiveness of human mononuclear leukocytes (HML) from hypertensive patients and matched normotensive volunteers. We also considered associations of these variables with plasma renin activity, aldosterone, cortisol, corticotropin, and electrolyte concentrations. We calculated binding affinity (Kd; nmol/L) and capacity (Bmax; sites/cell) for dexamethasone and cortisol from homologous and heterologous competition curves for specific [3H]dexamethasone binding sites on HML isolated from the blood of normotensive volunteers and subjects with essential hypertension. Glucocorticoid responsiveness of HML was evaluated as IC50 values (nmol/L) for dexamethasone and cortisol for the inhibition of lysozyme release. We measured plasma hormones by radioimmunoassay. Kd values (mean±SE) for cortisol in HML of hypertensive patients were higher than in control subjects (24.6±2.4 versus 17.5±1.7 nmol/L, P<.04). Binding capacity (4978±391 versus 4131±321 sites/cell), Kd values for dexamethasone (6.7±0.5 versus 5.7±0.3 nmol/L), and IC50 values for dexamethasone (3.4±0.3 versus 3.1±0.2 nmol/L) and cortisol (12.2±1.6 versus 9.5±0.3 nmol/L) were not significantly different. Patients with renin values less than 0.13 ng angiotensin I/L per second were markedly less sensitive to cortisol than those with higher values. Both Kd (30.3±2.5 versus 19.2±2.4 nmol/L) and IC50 values (15.5±1.8 versus 8.9±1.2 nmol/L) for cortisol were significantly higher in patients with lower renin values (P<.03). Other variables, including plasma hormone and electrolyte values and binding characteristics for dexamethasone, were not different. These data suggest that cortisol binding to glucocorticoid receptor is slightly impaired in patients with essential hypertension. In vivo, this could lead to inappropriate binding of cortisol to mineralocorticoid receptors. Hence, decreased sensitivity to cortisol is associated with renin suppression. This hypothesis is supported by evidence of hypertension and low renin activity, which others have described in patients with primary glucocorticoid resistance due to mutations of the glucocorticoid receptor.
Key Words: glucocorticoid receptors • hypertension • cortisol
|
Introduction |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
Glucocorticoid hormones play a key role in the control of blood pressure and are associated with hypertension in patients with Cushing's syndrome.1 Increases in blood pressure following cortisol or corticotropin administration are often associated with sodium and fluid retention, hypokalemia, and suppression of plasma renin activity, which are indicative of excess MR activity.2 It is also clear, however, from studies with synthetic steroids with negligible MR properties, that glucocorticoid hormones can raise blood pressure acting via type 2 adrenocorticosteroid receptors.3 The mechanisms of this glucocorticoid-induced hypertension are poorly understood but are known to involve modifications of vascular responsiveness to vasoconstrictors and vasodilators; the distribution of electrolytes between intracellular and extracellular compartments is also affected.4
Despite the fact that glucocorticoid hormones have potent effects on blood pressure, evidence that they are involved in the etiology of essential hypertension is equivocal. Two studies have demonstrated increased urinary excretion of the principal metabolites of cortisol in patients with essential hypertension.5 6 Numerous other studies have failed to demonstrate that corticosteroid production is excessive and, when abnormal circulating levels are present, they do not seem to be high enough for the elevated blood pressure. However, more recent molecular studies of processes regulating hormone access to receptor as well as postreceptor events have indicated a number of sites that potentially could alter sensitivity to glucocorticoid hormones without altering systemic hormone concentrations.7 If essential hypertension is a multifactorial, polygenic disease, then glucocorticoid hormones, which regulate the expression of so many of the genes controlling blood pressure, are likely to be involved secondarily.
Normally, plasma cortisol concentrations are maintained by negative-feedback control of pituitary corticotropin secretion, which is mediated via adrenocorticosteroid receptors. Exposure to excess cortisol could arise, therefore, only if receptor function were altered in a general or tissue-specific manner. For example, a point mutation in the glucocorticoid receptor gene causes primary glucocorticoid resistance with high corticotropin and cortisol levels in the absence of clinical features of Cushing's syndrome.8 This condition is associated with hypertension because, although type 2 adrenocorticosteroid function is impaired and feedback control of corticotropin secretion is lost, cortisol is able to exert MR-like effects via type 1 receptors.9 A case of hypersensitivity to cortisol has also been described, again caused by a mutation of the glucocorticoid receptor gene.10 This is associated with the symptoms of Cushing's syndrome but not hypertension (hypertension is not invariably present in Cushing's syndrome).
Such mutations of the glucocorticoid receptor gene are rare events and could not be expected to account for essential hypertension. More recently, a common polymorphism of the glucocorticoid receptor gene has been analyzed in a population study of the genetic determinants of hypertension.11 One of the allelic variants of the receptor gene was found to be more common in individuals with a familial disposition to develop hypertension. In the same group of individuals, plasma angiotensinogen (a glucocorticoid-dependent variable) and cortisol concentrations were slightly elevated. Although it has yet to be proven that this polymorphism alters receptor genotype, the concept that glucocorticoid function modulates blood pressure is established.
In the present study, we compare glucocorticoid binding properties and glucocorticoid responsiveness in white blood cells of patients with essential hypertension with those of normotensive control subjects. These values are considered in relation to plasma hormone values to determine whether receptor binding affects the pituitary-adrenal axis and to determine whether overall glucocorticoid activity secondarily affects MR activity.
|
Methods |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
Subjects
Eleven normotensive healthy volunteers (6 women and 5 men) age 25 to 45 years and 17 essential hypertensive subjects (10 women and 7 men) were sampled. All women were evaluated during the follicular phase, whereas hypertensive subjects were studied after screening to exclude known causes of secondary hypertension. None of the hypertensive subjects had evidence of cardiac, renal, or hepatic failure and diabetes mellitus. Alcohol and nicotine abuse were excluded. Antihypertensive therapy was discontinued for at least 21 days before the study.
All subjects were admitted between 8:00 A.M. and 9:00 A.M., and blood samples were collected after the subjects had been lying down for at least 30 minutes. Blood pressure was measured by conventional methods twice on the same occasion in each individual, supine and after standing for at least 5 minutes. The mean of the two readings was used for analysis. Height and weight were measured to calculate the BMI from the formula BMI=weight(kg)/height2(m). Venous blood was then drawn for routine biochemical and hormonal measurement and HML separation. A 24-hour urine specimen was obtained before visit to the clinic.
Cell Preparation
Peripheral blood obtained from fasting individuals
was collected into citrate, and platelet-rich plasma was removed by
low-speed centrifugation (600g for 5
minutes). The remaining cells were diluted 1:3 with PBS (0.85% NaCl
and 6.7 mmol/L phosphate, pH 7.2) and fractionated on a
Ficoll-Hypaque gradient according to the method of
Boyum.21 The layer of mononuclear cells was removed and
washed three times with PBS at room temperature by
centrifugation and resuspension to reduce platelet
contamination. The final pellet was resuspended in RPMI-1640 medium
containing 10% fetal calf serum, 1% penicillin, 1% streptomycin, and
1% glutamine. The cell viability was consistently higher than
95%, as evaluated by trypan blue dye exclusion. There were no changes
in cell number or viability during any incubation procedure.
Whole-Cell GR Assay
GR binding characteristics were measured by homologous and
heterologous competition for specific
[3H]dexamethasone-binding sites under
steady-state conditions.22 Briefly, 
3x106
HML resuspended in RPMI-1640 (supplemented with 1% glutamine) were
equilibrated with 2 nmol/L
[3H]dexamethasone and a range of
concentrations of unlabeled dexamethasone (0 to 150
nmol/L) and cortisol (0 to 600 nmol/L) by incubation for
3 hours at 24°C. Nonspecific binding was measured by incubating the
cells with a 1000-fold excess of unlabeled dexamethasone.
HML were harvested on Whatman GF/C filter paper and washed with
ice-cold PBS containing polyethylenimine (1 g/L) using a
Titertek cell harvester (Flow). Filters were treated with 1% Triton
X-100, and the radioactivity from lysed cells was measured by a liquid
scintillation spectrometer ( Beckman LS 1801).
Binding constants [Kd and binding capacity (Bmax)] were calculated from Scatchard plots that were fitted using the computer program Ligand.23 The data were compatible with a single-site model.
Lysozyme Assay
In vitro glucocorticoid responsiveness was measured by
inhibition of lysozyme synthesis by dexamethasone and
cortisol as previously described by Panarelli et al.24
Briefly, aliquots of cell suspensions (0.5 to 1x106 cells)
were cultured in a 96-well tissue culture plate at 37°C in 5%
CO2 for 72 hours in the presence of increasing
concentrations of dexamethasone (0 to 150 nmol/L)
and cortisol (0 to 600 nmol/L). After we centrifuged the
plates, we removed a 100-µL aliquot of supernatant from each
incubation well and stored it at -70°C. Lysozyme activity in the
supernatant was measured photometrically (Beckaman DU20) by the lysis
of Micrococcus lysodeikticus using human recombinant
lysozyme as a standard. Each sample was assayed in triplicate. For each
subject, the concentration of hormone that inhibits 50% of basal
production of lysozyme (IC50) was calculated.
Biochemical and Hormonal Measurement
Routine serum and urine measurements were carried out by
automated analyzer. A specific radioimmunoassay kit was used
for the determination of plasma cortisol (INCSTAR, Sorin Biomedica),
aldosterone (Sorin Biomedica), renin activity (Sorin
Biomedica), whereas plasma corticotropin was determined by specific
immunoradiometric assay (INCSTAR, Sorin Biomedica). Routine
hematological profiles were carried out by the cytofluorimetric
method.
Statistical Analysis
The mean±SEM for each variable were calculated. Linear
regression and correlation were calculated, and Student's t
test was used for the comparison of variables.
|
Results |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
The clinical and laboratory results are summarized in Table 1
. Serum uric acid,
cholesterol, and triglyceride were
significantly higher in the hypertensive group compared with the
normotensive group. Although serum creatinine was slightly
higher and urinary Na+/K+ ratio was lower in
the hypertensive group compared with the normotensive group, the
differences were not statistically significant. BMI, serum
electrolytes, hormonal levels, and hematological variables were
similar in the two groups.
|
Binding characteristics for dexamethasone and cortisol are
represented in Fig 1, and the
IC50 values for the inhibitory effects of
dexamethasone and cortisol on lysozyme activity in HML are
summarized in Fig 2. Both
dexamethasone and cortisol showed
Kd, but not Bmax, values
that positively correlated with the IC50 values for the
effects of the corresponding hormone on lysozyme activity
(R2=.8, P<.001 for
dexamethasone; R2=.9,
P<.001 for cortisol). Neither Kd nor
Bmax for dexamethasone and cortisol
correlated with either cortisol or corticotropin plasma
concentrations.
|
|
Dissociation constant values for cortisol in HML from hypertensive subjects were significantly higher than control subjects (24.6±2.4 versus 17.5±1.7 nmol/L, P<.04). Binding capacity (4978±391 versus 4131±321 sites/cell), Kd values for dexamethasone (6.7±0.5 versus 5.7±0.3 nmol/L), and IC50 values for dexamethasone (3.4±0.3 versus 3.1±0.2 nmol/L) and cortisol (12.2±1.6 versus 9.5±0.3 nmol/L) were not statistically different.
The hypertensive group was divided in two subgroups according to plasma
renin activity: (1) lower renin activity (n=8) defined as a basal
plasma renin activity <0.13 ng angiotensin I/L per second
and a plasma renin activity after 4 hours of walking of less than the
upper limit of 1 SD of the normal basal value; and (2) normal high
renin (n=9). Table 2 compares biochemical
and hormonal values in the two subgroups. The dissociation constant and
IC50 for dexamethasone and cortisol in these
two subgroups of hypertensive subjects are summarized in Figs 3 and 4. The
lower-renin hypertensive subgroup was markedly less sensitive, in
vitro, to cortisol compared with the subgroup with higher renin levels.
Both Kd (30.3±2.5 versus 19.2±2.4
nmol/L) and IC50 (15.5±1.8 versus 8.9±1.2
nmol/L) for cortisol were significantly high in the lower-renin
subgroup (P<.03). The binding capacity,
Kd, and IC50 for
dexamethasone were not significantly different between the
two subgroups. Although plasma corticotropin and cortisol were slightly
higher and the urinary Na+/K+ ratio was
decreased in the lower-renin subgroup, the differences were not
statistically significant (see Table 2).
|
|
|
|
Discussion |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
Endogenous GR are bound with similar affinities to MR and GR receptors, although access to MR in key tissues is restricted by enzymes that metabolize cortisol.12 13 Excess cortisol can cause hypertension by activation of GR and, after overcoming the enzyme barrier that protects MR, by promoting sodium retention and plasma volume expansion.2 Normally, however, feedback inhibition of pituitary corticotropin secretion by cortisol would reduce adrenal steroidogenesis to maintain homeostatic control of circulating concentrations of glucocorticoid hormones. It follows that cortisol might be expected to influence blood pressure if (1) the amount of added cortisol exceeds the compensatory capacity of the adrenal gland, (2) enzymes that metabolize cortisol are deficient, or (3) if GR binding properties are abnormal. In previous studies addressing the second possibility, a deficiency of 11ß-hydroxysteroid dehydrogenase has been shown to cause the syndrome of apparent MR excess.14 15 The deficiency is characterized by high ratios of cortisol to cortisone metabolites. In the patients with essential hypertension, although overt signs of MR excess are not apparent, there have been several reports suggesting abnormalities of cortisol metabolism.5 6 16 The present study has addressed the third possibility by measuring GR binding properties and by assessing glucocorticoid responsiveness of patients with essential hypertension and of normotensive control subjects.
Although the synthetic glucocorticoid dexamethasone is used most often in these types of tests, in our earlier experience with a rat genetic model of hypertension we noted that differences between Milan hypertensive and normotensive strains in binding for endogenous ligands (corticosterone and aldosterone) were greater than that for dexamethasone.17 Accordingly, we considered both dexamethasone and cortisol in measurements of steroid binding properties and in steroid-induced inhibition of white blood cell lysozyme synthesis. When comparing the normotensive group with the entire hypertensive group, we noted that affinity for cortisol, but not dexamethasone, was lower in hypertensive subjects than in control subjects. The reason cortisol, but not dexamethasone, binding affinities were affected is not clear. Although in vivo cortisol is metabolized more readily than dexamethasone, this cannot account for the present in vitro observations.18 In previous unpublished studies, we incubated white blood cells from normal volunteers with cortisol for periods up to 72 hours (ie, the time course for lysozyme assay). When cells and medium were extracted and analyzed chromatographically at the end of this time, only the parent compound was recovered. It follows that if metabolism does not affect cortisol activity in cells from normal individuals, a metabolic deficiency cannot account for the discrepancy between affinities for dexamethasone and cortisol in hypertensive subjects. It is possible that there are also minor differences in dexamethasone binding but that like the Milan rats, the magnitude is much lower for higher-affinity ligands.
In the case of Milan rats, there are a number of differences in the coding region of the GR gene that may be associated with low-affinity binding. In humans, mutations that cause reduced steroid binding are relatively rare. The few glucocorticoid resistance cases that have been reported appear to have variable etiologies and side effects.8 19 20 A more common mutation affecting approximately 10% of a healthy population has been described, but this is associated with increased not decreased sensitivity.
For both dexamethasone and cortisol, the IC50 values for steroid-induced inhibition of lysozyme release correlated with Kd values for receptor binding studies. As might be expected, therefore, there were no significant differences in lysozyme release between control subjects and hypertensive patients. For cortisol, IC50 values (in line with Kd values) were 25% higher in the hypertensive than in the normotensive group, but this difference was not statistically significant.
Among patients with essential hypertension, a significant subgroup with lower plasma renin but normal aldosterone concentrations has been identified. Working on the premise that MR excess is characterized by suppression of renin activity, many groups have focused on novel steroid hormones with potent MR activity to explain these low renin values. As outlined above, however, low renin values might also be a consequence of cortisol acting on MR. In the present context, impaired GR binding leads to reduced feedback inhibition of corticotropin secretion and raised plasma cortisol concentrations which, acting on MR in transporting epithelia, could cause an antinatriuresis, renin suppression, and hypertension. When comparing all hypertensive patients with the control group, there were no differences in plasma renin activity. However, when patients with high- and low-renin groups were analyzed separately, it became apparent that hypertensive subjects in the lower-renin group had higher Kd values and showed reduced sensitivity to cortisol-induced lysozyme release compared with the high/normal–renin subgroup; the latter group had white blood cells that showed similar steroid binding properties and steroid-sensitive lysozyme release to those from normotensive control subjects.
One would predict, theoretically, that if GR impairment causes MR activation, then this should be mediated by raised plasma cortisol concentrations which, in turn, should be driven by increased corticotropin secretion. No such differences in plasma cortisol and corticotropin were observed. It could be argued, however, that a single-point measurement of cortisol and corticotropin does not reflect the complex circadian control of the hypothalamus-pituitary-adrenal axis. A test using low-dose cortisol (not dexamethasone) to suppress corticotropin would be required that should also take account of the influence of the 11ß-hydroxysteroid dehydrogenase enzymes.
The association of GR binding and suppression of renin activity might also suggest that electrolyte metabolism could be affected. Hypokalemia was not seen in patients with lower renin values, but there was a tendency for the urinary sodium/potassium ratio to be decreased. This lack of a significant effect is not surprising because no attempt was made in the present investigations to control dietary intake of electrolytes. Others have also failed to show a link of urinary or plasma electrolytes and blood pressure in patients with essential hypertension.
An alternative view of the present results is that changes in plasma renin activity and receptor binding characteristics are a consequence rather than a contributory cause of hypertension. Although there are considerable data to indicate that expression of steroid hormone receptors and, therefore, binding capacity might be regulated, there is no evidence that receptor affinity and specificity are regulated other than via steroid-metabolizing enzymes. Although there is evidence in vivo of altered steroid metabolism in patients with essential hypertension,5 6 16 it does not seem to apply to our in vitro studies of receptor binding and glucocorticoid-dependent inhibition of lysozyme release. We are unaware of any mechanism whereby blood pressure or the consequences of hypertension could account for our findings.
In contrast to our present findings, Walker et al25 report increased peripheral glucocorticoid sensitivity in vivo associated with higher affinity of GR for dexamethasone in vitro in subjects predisposed to high blood pressure. Although these results seem contradictory, it should be remembered that glucocorticoid hormones, independent of MR-like actions, increase blood pressure.4 It follows that increased affinity of GR for the ligand would potentiate glucocorticoid-dependent processes and therefore increase blood pressure. Taking these data together, therefore, a plot of blood pressure against GR should be U-shaped; one limb of the U should be associated with normal renin values and reduced plasma cortisol concentrations, and the other limb should be associated with low renin values and raised plasma cortisol concentration.
In conclusion, our results show that in patients with essential hypertension, there is a subgroup that exhibits slightly impaired glucocorticoid binding. This effect is specific to cortisol and not dexamethasone and leads to reduced glucocorticoid responsiveness of white blood cells in vitro. This difference in steroid binding may secondarily increase MR activity and therefore could be a contributory cause of low renin values and higher blood pressure in these patients. The molecular mechanism underlying this difference in receptor binding remains to be elucidated.
|
Selected Abbreviations and Acronyms |
|---|
|
Received February 10, 1996; first decision March 17, 1996; accepted June 2, 1997.
|
References |
|---|
|
TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
1. Fraser R, Davies DL, Connell JMC. Hormones and hypertension. Clin Endocrinol. 1989;31:701-746.[Medline] [Order article via Infotrieve]
2. Connell JMC, Whitworth JA, Davies DL. Effects of ACTH and cortisol administration on blood pressure, electrolyte metabolism, atrial natriuretic peptide and renal function in normal man. J Hypertens. 1987;5:425-433.[Medline] [Order article via Infotrieve]
3. Tonolo G, Fraser R, Connell JMC, Kenyon CJ. Chronic low-dose infusion of dexamethasone in rats: effects on blood pressure, body weight and plasma atrial natriuretic peptide. J Hypertens. 1988;6:25-31.[Medline] [Order article via Infotrieve]
4. Kenyon CJ, Morton JJ. Experimental steroid-induced hypertension. In: Swales JD, ed. Textbook of Hypertension. Oxford, UK: Blackwell Scientific Publications; 1993:494-500.
5.
Kornel L, Starnes WR, Hill Jr SR, Hill A.
Studies on steroid conjugates. VI. Quantitative paper
chromatography of urinary
corticosteroids in essential hypertension.
J Clin Endocrinol Metab. 1969;29:1608-1617.
6.
Soro A, Ingram MC, Tonolo G, Glorioso N, Fraser
R. Evidence of co-existing changes in 11ß-hydroxysteroid
dehydrogenase and 5ß-reductase activity in subjects with untreated
essential hypertension. Hypertension. 1995;25:67-70.
7.
Bamberger CM, Schulte HM, Chrousos GP.
Molecular determinants of glucocorticoid receptor function and tissue
sensitivity to glucocorticoids. Endocr Rev. 1996;17:245-261.
8. Chrousos GP, Vingerhoed A, Brandon D, Eil C, Pugeat M, De Vroede M, Loriaux DL, Lipsett MB. Primary cortisol resistance in man. A glucocorticoid receptor-mediated disease. J Clin Invest. 1982;69:1261-1269.
9. Lamberts SWJ, Koper JW, Biemond P, de Holder FH, de Jong FH. Cortisol receptor resistance: the variability of its clinical presentation and response to treatment. J Clin Endocrinol Metab. 1992;74:313-321.[Abstract]
10. Lamberts SWJ, Molijn GJ, Huizenga NTM, de Jong FH, Koper JW. The glucocorticoid receptor in health and disease. J Endocrinol. 1994;143(suppl 1):O1.
11. Watt GCM, Harrap SB, Foy CJW, Holton DW, Edwards HW, Davidson HR, Connor JM, Lever AF, Fraser R. Abnormalities of glucocorticoid metabolism and the renin-angiotensin system: a four corner approach to the identification of the genetic determinants of blood pressure. J Hypertens. 1992;10:473-482.[Medline] [Order article via Infotrieve]
12. Edwards CRW, Burt D, McIntyre MA, de Kloet ER, Stewart PM, Brett LP, Sutanto WS, Monder C. Localization of 11ß-hydroxysteroid dehydrogenase-tissue specific protector of the mineralocorticoid receptor. Lancet. 1989;ii:986-989.
13.
Funder JW, Pearce PT, Smith R, Smith AL.
Mineralocorticoid action: target tissue specificity is enzyme not
receptor mediated. Science. 1988;242:583-585.
14. Stewart PM, Corrie JET, Shackleton CHL, Edwards CRW. Syndrome of apparent mineralocorticoid excess: a defect in the cortisol-cortisone shuttle. J Clin Invest. 1998;82:340-349.
15. Obeyesekere VR, Ferrari P, Andrews RK, Wilson RC, New ML, Funder JW, Krozowski ZS. The R337C mutation generates a high Km 11ß-hydroxysteroid dehydrogenase type II enzyme in a family with apparent mineralocorticoid excess. J Clin Endocrinol Metab. 1995;80:3381-3383.[Abstract]
16. Walker BR, Stewart PM, Shackleton CHL, Padfield PL, Edwards CRW. Deficient inactivation of cortisol by 11ß-hydroxysteroid dehydrogenase in essential hypertension. Clin Endocrinol. 1993;39:221-227.[Medline] [Order article via Infotrieve]
17. Panarelli M, Holloway CD, Fraser R, Kenyon CJ. Evidence of an impaired glucocorticoid receptor in Milan hypertensive rats. J Endocrinol. 1994;140(suppl):P21.
18.
Walker BR, Williams BC, Edwards CRW. Regulation
of 11ß-hydroxysteroid dehydrogenase activity by the
hypothalamic-pituitary-adrenal axis in the rat. J
Endocrinol. 1994;141:467-472.
19. Arai K, Chrousos GP. Glucocorticoid resistance. Bailliere's Clin Endocrinol Metab. 1994;8:317-331.[Medline] [Order article via Infotrieve]
20. Panarelli M, Fraser R. The glucocorticoid receptor and hypertension. Endocr Res. 1994;20:101-106.[Medline] [Order article via Infotrieve]
21. Boyum A. Isolation of mononuclear cells and granulocytes from human blood. Isolation of mononuclear cells by one centrifugation and of granulocytes by combining centrifugation and sedimentation at 1G. Scand J Clin Lab Invest. 1968;21(suppl):77-89.
22. Schlechte JA, Ginsberg BH, Sherman BM. Regulation of the glucocorticoid receptor in human lymphocytes. J Steroid Biochem. 1982;16:69-74.[Medline] [Order article via Infotrieve]
23. Munson PJ, Rodbard D. Ligand: a versatile computerized approach for characterization of ligand-binding systems. Anal Biochem. 1980;107:220-239.[Medline] [Order article via Infotrieve]
24. Panarelli M, Holloway CD, Mulatero P, Fraser R, Kenyon CJ. Inhibition of lysozyme synthesis by dexamethasone in human mononuclear leukocytes: an index of glucocorticoid sensitivity. J Clin Endocrinol Metab. 1994;78:872-877.[Abstract]
25. Walker BR, Noon JP, Panarelli M, Best R, Holton DW, Edwards HV, Edwards CRW, Watt GCM, Webb DJ. Increased glucocorticoid receptor affinity and sensitivity in subjects predisposed to high blood pressure. J Hypertens. 1996;14(suppl 1):P655.
This article has been cited by other articles:
 |
|
 |
|
  B. Chamarthi, N. S. Kolatkar, S. C. Hunt, J. S. Williams, E. W. Seely, N. J. Brown, L. J. Murphey, X. Jeunemaitre, and G. H. Williams Urinary Free Cortisol: An Intermediate Phenotype and a Potential Genetic Marker for a Salt-Resistant Subset of Essential Hypertension J. Clin. Endocrinol. Metab., April 1, 2007; 92(4): 1340 - 1346. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 W Shamim, M Yousufuddin, D P Francis, P Gualdiero, J W Honour, S D Anker, and A J S Coats Raised urinary glucocorticoid and adrenal androgen precursors in the urine of young hypertensive patients: possible evidence for partial glucocorticoid resistance Heart, August 1, 2001; 86(2): 139 - 144. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. A. Whitworth, G. J. Mangos, and J. J. Kelly Cushing, Cortisol, and Cardiovascular Disease Hypertension, November 1, 2000; 36(5): 912 - 916. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. C. Y. Lin, W. Y. S. Wang, and B. J. Morris Association and Linkage Analyses of Glucocorticoid Receptor Gene Markers in Essential Hypertension Hypertension, December 1, 1999; 34(6): 1186 - 1192. [Abstract] [Full Text] [PDF]
|
|
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||