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Biomedical subjects

A Racadot

Publications and source records attributed to A Racadot.

At least 19 recordsLinked to original sources
PubMed2000

Bone ultrasonometry and turnover markers in primary hyperparathyroidism.

Quantitative ultrasound (QUS) of bone and new markers of bone remodeling have been poorly investigated in mild primary hyperparathyroidism (PHPT). In this study 26 patients (20 females and 6 males) were evaluated. BUA and SOS were measured by QUS at the heel. Markers of bone remodeling assessed were bone alkaline phosphatase (BAP), osteocalcin (OC), procollagen type I N- and C-terminal propeptides (PINP et PICP), and procollagen type I C-terminal telopeptide in blood and urine (ICTP and CTX). Bone mineral density (BMD) was measured at the lumbar spine (LS), femoral neck (FN), and Ward's triangle (WT). The control group comprised 35 sex- and age-matched subjects. The statistically significant variables between the two groups were (P < 0.05) BUA, BMD(LS), BMD(FN), BMD(WT), BAP, and OC. Corresponding z-scores were -0.55 +/- 0.75, -0.66 +/- 0.77, -0.66 +/- 0.71, -0.67 +/- 0.52, 1.87 +/- 3.87, and 1.93 +/- 3.53, respectively. Although PICP and PINP levels were higher in PHPT patients as compared with controls, the difference was not significant. Several markers of bone turnover were moderately correlated with both QUS (r = -0.39 to -0.55) and BMD (r = -0.48 to 0.63). In conclusion QUS seems to be a relevant tool in the assessment of bone status for patients with mild PHPT.

Absorptiometry, Photon↗
PubMed1999

Quantitative analysis of human serum corticosterone by high-performance liquid chromatography coupled to electrospray ionization mass spectrometry.

An original method based upon high-performance liquid chromatography coupled to electrospray ionization mass spectrometry has been developed for corticosterone (B) quantification in human serum. After extraction by diethyl ether using triamcinolone (T) as an internal standard, solutes are separated on a C18 microbore column (250 X 1.0 mm, I.D.), using acetonitrile-water-formic acid (40:59.9:0.1, v/v/v) as the mobile phase (flow-rate 40 microl/min). Detection is performed on an API 1 single quadrupole mass spectrometer equipped with a ESI interface and operated in positive ionization mode. Corticosterone quantifications were realized by computing peak area ratios (B/T) of the serum extracts analyzed in SIM mode (m/z 347 and m/z 395 for B and T. respectively), and comparing them with the calibration curve (r=0.998).

Calibration↗
PubMed1999

Transient pseudo-hypoaldosteronism following resection of the ileum: normal level of lymphocytic aldosterone receptors outside the acute phase.

Pseudo-hypoaldosteronism (PHA) is due to mineralocorticoid resistance and manifests as hyponatremia and hyperkalemia with increased plasma aldosterone levels. It may be familial or secondary to abnormal renal sodium handling. We report the case of a 54-year-old woman with multifocal cancer of the colon, who developed PHA after subtotal colectomy, ileal resection and jejunostomy. She was treated with 6 g of salt daily to prevent dehydration, which she stopped herself because of reduced fecal losses. One month later she was admitted with signs of acute adrenal failure, i.e. fatigue, severe nausea, blood pressure of 80/60 mmHg, extracellular dehydration, hyponatremia (118 mmol/l); hyperkalemia (7.6 mmol/l), increased blood urea nitrogen (BUN) (200 mg/dl) and creatininemia (2.5 mg/dl), and decreased plasma bicarbonates level (HCO3-: 16 mmol/l; N: 27-30). However, the plasma cortisol was high (66 microg/100 ml at 10:00 h; N: 8-15) and the ACTH was normal (13 pg/ml, N: 10-60); there was a marked increase in plasma renin activity (>37 ng/ml/h; N supine <3), active renin (869 pg/ml; N supine: 1.120), aldosterone (>2000 pg/ml; N supine <150) and plasma AVP (20 pmol/l; N: 0.5-2.5). The plasma ANH level was 38 pmol/l (N supine: 5-25). A urinary steroidogram resulted in highly elevated tetrahydrocortisol (THF: 13.3 mg/24h; N: 1.4+/-0.8) with no increase in tetrahydrocortisone (THE: 3.16 mg/24h; N: 2.7+/-2.0) excretion, and with low THE/THF (0.24; N: 1.87+/-0.36) and alpha THF/THF (0.35; N: 0.92+/-0.42) ratios. The number of mineralocorticoid receptors in mononuclear leukocytes was in the lower normal range for age, while the number of glucocorticoid receptors was reduced. Small-bowel resection in ileostomized patients causes excessive fecal sodium losses and results in chronic sodium depletion with contraction of the plasma volume and severe secondary hyperaldosteronism. Nevertheless, this hyperaldosteronism may be associated with hyponatremia and hyperkalemia suggesting PHA related to the major importance of the colon for the absorption of sodium. In conclusion, this case report emphasizes 1) the possibility of a syndrome of acquired PHA with severe hyperkalemia after resection of the ileum and colon responding to oral salt supplementation; 2) the major increase in AVP and the small increase in ANH; 3) the strong increase in urinary THF with low THE/THF and alpha THF/THF ratios; 4) the normal number of lymphocytic mineralocorticoid receptors outside the acute episode.

Colectomy↗
PubMed1998

Urinary cortisol metabolites in the assessment of peripheral thyroid hormone action: overt and subclinical hypothyroidism.

UNLABELLED: Biological assessment of peripheral thyroid hormone action may be important in subclinical hypothyroidism, where decision-making is often difficult. The impairment of urinary cortisol metabolites in overt hypothyroidism reflects an acquired 11 beta hydroxysteroid dehydrogenase (11 beta OHSD) deficiency, and is assessed in terms of a reduction in the tetrahydrocortisone (THE)/tetrahydrocortisol (THF) ratio or THE/THE + alpha THF ratio; the alpha THF/THF ratio reflects 5 beta reductase activity. The aim of this study was to determine if urinary cortisol metabolite ratios are a good index of peripheral thyroid hormone action in subclinical hypothyroidism. MATERIALS AND METHODS: the THE/THF, THE/THF + alpha THF and alpha THF/THF ratios were measured in 24 h urine samples from 3 groups of subjects: 1) 18 euthyroid subjects; 2) 25 patients with elevated serum TSH and low FT4 levels (overt hypothyroidism); and 3) 25 patients with increased serum TSH and normal FT4 levels (subclinical hypothyroidism. RESULTS: 7/25 overtly and 5/25 subclinically hypothyroid patients had a THE/THF + alpha THF ratio below the mean control value -2 SD, while respectively 20/25 and 11/25 patients had a THE/THF ratio below the mean control value -2 SD. The mean THE/THF + alpha THF, THE/THF and alpha THF/THF ratios were significantly different among the 3 groups (ANOVA) and were lower in the overtly hypothyroid group than in the other two groups (Fisher's test); daily urine sodium output was also significantly different between the three groups and lower in the overtly and subclinically hypothyroid groups than in the control group (Fisher's test). FT3 and FT4 both correlated with THE/THF + alpha THF in the overtly hypothyroid patients (r = 0.43; p < 0.05 and r = 0.40; p < 0.05, respectively). In the subclinically hypothyroid patients, TSH correlated with THE/THF + alpha THF (r = 0.44; p < 0.05) and THE/THF (r = 0.43; p < 0.05). FT3, FT4 and TSH levels correlated with THE/THF + alpha THF (p < 0.001), THE/THF (p < 0.001), alpha THF/THF (p < 0.001) and daily natriuresis (p < 0.05) in the whole population (patients + controls). In conclusion, urinary cortisol metabolites, although impaired in overt hypothyroidism, are not an accurate index of peripheral thyroid hormone deficiency in subclinical hypothyroidism. We also identified an increase in the alpha THF/THF ratio in overt hypothyroidism, which may be related to 5 beta reductase disturbances.

11-beta-Hydroxysteroid Dehydrogenases↗
PubMed1998

Hypocalcemia following thyroid surgery: incidence and prediction of outcome.

Postoperative hypocalcemia is a common and most often transient event after extensive thyroid surgery. It may reveal iatrogenic injury to the parathyroid glands and permanent hypoparathyroidism. We prospectively evaluated the incidence of hypocalcemia and permanent hypoparathyroidism following total or subtotal thyroidectomy in 1071 consecutive patients operated during 1990-1991. We then determined in a cross-sectional study which early clinical and biochemical characteristics of patients experiencing postoperative hypocalcemia correlated with the long-term outcome. Postoperative calcemia under 2 mmol/l was observed in 58 patients (5. 4%). In 40 patients hypocalcemia was considered severe (confirmed for more than 2 days, symptomatic or both). At 1 year after surgery five patients (0.5%) had persistent hypocalcemia. We found that patients carried a high risk for permanent hypoparathyroidism if fewer than three parathyroid glands were preserved in situ during surgery or the early serum parathyroid hormone level was </= 12 pg/ml, the delayed serum calcium levels </= 8 mg/dl, or the delayed serum phosphorus level >/= 4 mg/dl under oral calcium therapy. When one or more of these criteria are present, long-term follow-up should be enforced to check for chronic hypocalcemia and to avoid its severe complications by appropriate supplement therapy.

Cross-Sectional Studies↗
PubMed1998

Essential hypertension: first reason for persistent hypertension after unilateral adrenalectomy for primary aldosteronism?

BACKGROUND: Despite cure of primary aldosteronism by surgical resection, hypertension persists postoperatively in 30% to 50% of patients. The aim of this study was to determine factors influencing long-term outcome of blood pressure after unilateral adrenalectomy for primary aldosteronism. METHODS: Records of 100 patients who underwent unilateral adrenalectomy for primary aldosteronism from 1970 through 1997 were reviewed. Patients were distributed in 2 groups according to whether blood pressure was normal (criteria of World Health Organization). Clinical, biochemical, and pathologic data were compared. RESULTS: All patients were biochemically cured. Blood pressure was normal in 56 patients and improved in 44 (mean follow-up, 69 and 59 months). Persistent hypertension correlated with age, known duration and seriousness of preoperative hypertension, family history of hypertension, no preoperative response to spironolactone, and contralateral adrenal hypertrophy. Gender, surgical approach, and pathologic findings were not predictive factors of blood pressure outcome. The prevalence of hypertension was almost the same in these postoperative patients as the prevalence of essential hypertension in a random population of the same age. CONCLUSIONS: Early unilateral adrenalectomy allows cure or improvement of hypertension in all patients with primary aldosteronism induced by unilateral excessive source of aldosterone secretion regardless of the pathologic findings. Persistent hypertension suggests that coexisting essential hypertension is present.

Adolescent↗
PubMed1998

Localization of abnormal parathyroid glands with jugular sampling for parathyroid hormone, and subtraction scanning with sestamibi or tetrofosmine.

BACKGROUND: Accurate pre-operative localization of abnormal parathyroid glands is an essential prerequisite for elective surgical approaches such as the unilateral approach for treatment of primary hyperparathyroidism. METHODS: In 175 patients undergoing a bilateral neck exploration for primary hyperparathyroidism, localization of abnormal parathyroid glands was performed with jugular venous sampling for parathyroid hormone (PTH, n = 75), subtraction scan with iodine 123 and technetium-99m-sestamibi (MIBI, n = 50), or tetrofosmine (TTF, n = 50). The results of these localization studies were compared with operative findings. RESULTS: The sensitivity of PTH, MIBI, and TTF was 41, 63, and 71%, respectively. The specificity was 90, 98, and 98% and the positive predictive value was 85%, 82%, and 87%, respectively. The smallest abnormal parathyroid that was correctly detected weighed 110 mg with PTH, 118 mg with MIBI, and 70 mg with TTF. Subtraction scan (MIBI and TTF) detected mediastinal glands in five cases out of six. In patients with multiglandular disease, the results of all three studies were severely impaired. CONCLUSIONS: Subtraction scanning with MIBI or TTF, but not jugular sampling for PTH, appeared to be useful for localization of abnormal parathyroid glands in patients with primary hyperparathyroidism. Nevertheless, an elective unilateral approach guided by the localization studies would not have allowed the excision of all abnormal parathyroid glands in patients with multiglandular disease.

Female↗
PubMed1997

Serum alpha-inhibin levels in polycystic ovary syndrome: relationship to the serum androstenedione level.

To date, only one study has demonstrated increased serum inhibin levels in women with polycystic ovary syndrome (PCOS). Moreover, no relationship between serum inhibin and either FSH or androgen levels has been noted. This lack of data could be due to 1) the heterogeneity of PCOS and the small sample size of previous studies, and/or 2) the complexity of circulating inhibin molecular forms, which hinders the precise evaluation of bioactive inhibin. In the present study, alpha-inhibin levels were assayed in the serum of 61 healthy women and 72 PCOS patients by means of an alpha-alpha enzyme-linked immunosorbent assay. Serum alpha-inhibin levels together with LH and androstenedione (A) levels were significantly increased in PCOS women (mean +/- SD, 1.45 +/- 0.55 vs. 0.94 +/- 0.36 U/mL in controls; P < 0.001). Moreover, simple and partial regression analysis demonstrated that serum A levels were positively and independently correlated to serum alpha-inhibin (r = 0.32; P < 0.01) and LH levels (r = 0.48; P < 0.001) in PCOS. The respective influences of alpha-inhibin and LH on A variability were 20% and 80%, as determined by multiple regression analysis. In conclusion, in agreement with recent in vitro data, our in vivo results argue for a role of inhibin in the hyperandrogenism of PCOS together with, but independently from, that of LH. Further studies are needed to determine whether this effect is produced by inhibin A and/or B.

Adolescent↗
PubMed1997

How useful are bone turnover markers in rheumatoid arthritis? Influence of disease activity and corticosteroid therapy.

UNLABELLED: Rheumatoid arthritis is associated with osteopenia possibly related to increased bone resorption. Until recently, the markers used to evaluate bone turnover lacked specificity, and as a result studies were difficult to interpret. OBJECTIVES: To study bone remodeling in patients with rheumatoid arthritis, with special attention to the effects of corticosteroid therapy. PATIENTS AND METHODS: Forty-eight patients (36 women and 12 men) with a mean age of 54.6 +/- 11.6 years and a mean disease duration of 11 +/- 9 years were studied. Thirty-nine patients (81%) had positive tests for rheumatoid factors, and 21 (43.7%) were under corticosteroid therapy, with a mean treatment duration of 4.5 +/- 2.9 years and a mean daily dosage of 9.4 +/- 2.5 mg prednisone. A group of age- and sex-matched controls was also studied. Serum levels of procollagen Type I C-terminal propeptide (PINP), procollagen Type I N-terminal propeptide (PINP), and procollagen type I C-terminal telopeptide (ICTP) were determined in all patients and controls. The first two markers reflect bone formation and the last bone resorption. Other tests performed in each patient were the erythrocyte sedimentation rate, serum C-reactive protein, serum total alkaline phosphatase, serum osteocalcin, 24-hour urinary hydroxyproline excretion, and calcium/creatinine ratio in a morning urine sample. Several clinical parameters were used to evaluate disease activity and severity in the rheumatoid arthritis patients. RESULTS: ICTP levels were significantly elevated in the patients as compared with the controls (6.6 +/- 3.9 ng/ml versus 3.1 +/- 1.2 ng/ml, P = 0.0001), whereas no significant differences were found for PICP or PINP. Similar results were found when the analysis was confined to nonsteroid-medicated patients. Conversely, PICP levels were higher in steroid-medicated patients than in controls (P = 0.0132) and were correlated with steroid therapy duration (r = 0.436). ICTP levels were correlated with age (r = 0.3), Lee's index (r = 0.585), the Health Assessment Questionnaire score (r = 0.391), and the erythrocyte sedimentation rate (r = 0.442). Urinary hydroxyproline excretion was elevated in 41.6% of the patients. CONCLUSION: Our data suggest that rheumatoid arthritis is associated with increased bone resorption, and that steroid therapy further accelerates bone remodeling in this disease.

Adrenal Cortex Hormones↗
PubMed1997

Plasma levels of atrial natriuretic peptide at peak exercise: a prognostic marker of cardiovascular-related death and heart transplantation in patients with moderate congestive heart failure.

BACKGROUND: Conflicting data have been published concerning exercise performance and hormonal activation. Previous studies have demonstrated the prognostic information of plasma levels of neurohormones at rest in patients with congestive heart failure. No study has examined the prognostic information of plasma levels of hormones at peak exercise. METHODS: Fifty-five consecutive ambulatory patients with stable moderate congestive heart failure (New York Heart Association class II to III) performed a maximal symptom limited cardiopulmonary exercise test with the determination of peak oxygen consumption. Blood samples were drawn at rest and at peak exercise for the determination of plasma levels of atrial natriuretic peptide, aldosterone, and plasma renin activity. RESULTS: Hormonal activation was present at rest, and exercise significantly increased hormonal values. There was no correlation between exercise parameters and hormonal values either at rest or at peak exercise. After a median follow-up period of 724 days, in univariate and multivariate Cox analysis, the most significant independent prognostic marker was the plasma level of atrial natriuretic peptide at peak exercise. Patients with a plasma level of atrial natriuretic peptide > 38 pmol/L had an event rate of 48% compared with an event rate of 14.8% in the other subgroup (p < 0.01). CONCLUSIONS: In patients with stable moderate congestive heart failure, exercise increased hormonal values, but there was no relationship between hormonal activation and exercise performance. Plasma level of atrial natriuretic peptide at peak exercise was the most significant independent marker of cardiovascular-related death and of cardiovascular-related death and heart transplantation.

Adult↗
PubMed1996

[Family of inhibins and activins: from endocrine to paracrine action].

Inhibins and activins are structurally-related dimeric proteins mainly produced by the gonads (Sertoli cells and granulosa cells) under the stimulation of pituitary FSH. Inhibins are 32-kD glycoproteins consisting of an alpha subunit and one of two beta subunits (beta A or beta B) leading to inhibin A or B, respectively. Activins are made of two beta subunits either identical (activin A or B) or not (activin AB). These regulatory peptides are involved in an endocrine feedback loop: inhibins decrease and activins stimulate the biosynthesis and release of pituitary FSH selectively. Beside their endocrine action that has led to the discovery of these peptides, we report main experimental data showing that activins and inhibins may act as paracrine and autocrine factors within the gonads on an antagonistic mode. Inhibins and activins seem to be involved in the regulation of spermatogenesis in males and in follicular maturation in females. Potential involvements of inhibins and activins in the pathophysiology of reproduction are discussed.

Activin Receptors↗
PubMed1995

Plasma levels of endothelin-1 at rest and after exercise in patients with moderate congestive heart failure.

Plasma levels of endothelin-1 are increased in patients with severe congestive heart failure related to various etiologies. However, conflicting data have been published in patients with moderate congestive heart failure. Moreover, the effect of exercise on plasma levels of endothelin-1 is not precisely known. We determined the plasma levels of endothelin-1 in a homogenous group of patients with idiopathic dilated cardiomyopathy in stage II of the New York Heart Association functional classification at rest and at peak exercise. In this group of patients, plasma levels of endothelin-1 were increased compared to a control group (2.9 +/- 0.27 vs. 1.96 +/- 0.24 pmol/l, P < 0.01, mean +/- S.E.M.), as were plasma levels of atrial natriuretic peptide (26.3 +/- 6.3 vs. 2.95 +/- 0.7 pmol/l, P < 0.001), plasma renin activity (12.6 +/- 2.98 vs. 1.75 +/- 0.23 ng/ml per h, P < 0.001) and plasma levels of aldosterone (217 +/- 29.3 vs. 154 +/- 18.8 pg/ml, P < 0.05). In contrast to the other hormones, exercise did not increase plasma levels of endothelin-1. There was no correlation between plasma levels of endothelin-1 and plasma levels of atrial natriuretic peptide, and no correlation between left ventricular ejection fraction, peak oxygen consumption and hormonal values. In conclusion, plasma levels of endothelin-1 are increased in a homogeneous group of patients with idiopathic dilated cardiomyopathy and moderate congestive heart failure. Endothelin-1 could participate in the progression of heart failure. Exercise did not increase the plasma levels of endothelin-1 in contrast to the other hormones.

Adult↗
PubMed1995

Neointimal thickening after balloon denudation is enhanced by aldosterone and inhibited by spironolactone, and aldosterone antagonist.

OBJECTIVE: The aim was to examine the effects of aldosterone and of an aldosterone antagonist, spironolactone, on neointimal thickening in a rabbit model of balloon injury. METHODS: Eighteen rabbits underwent aortic and iliac balloon injury and were randomised to subcutaneous infusion of aldosterone (70 micrograms.kg-1.d-1) or vehicle solution for 28 d. Eighteen other rabbits were randomised to receive daily subcutaneous injections of spironolactone (50 mg.kg-1.d-1) or of vehicle for 7 d before injury and for 28 d after the procedure. All animals were then killed just after measurement of plasma renin activity and of arterial pressure. Vessels were fixed and five cross sections were analysed per rabbit (three aortic; two from iliac artery). Mean values of neointimal area and of the neointimal area/medial area ratio were calculated. RESULTS: Aldosterone treatment was associated with a decrease in renin activity and a non-significant increase in mean arterial pressure. Aldosterone significantly augmented the neointimal thickening in the iliac artery [0.42(SEM 0.07) v 0.24(0.03) mm2, P < 0.05] but not in the aorta [0.63(0.08) v 0.59(0.12) mm2, NS]. Spironolactone significantly inhibited intimal thickening, both in the iliac artery [0.09(0.02) v 0.29(0.01) mm2, P < 0.001] and in the aorta [0.31(0.03) v 0.59(0.06) mm2, P < 0.001]. Spironolactone administration was associated with an increase in renin activity and a decrease in mean arterial blood pressure. CONCLUSIONS: Aldosterone administration enhances neointimal thickening after injury and spironolactone, an aldosterone antagonist, is a potent inhibitor of neointimal thickening in the same model. This suggests a role for aldosterone in the pathophysiology of neointimal proliferation after balloon injury and for aldosterone antagonists in its prevention.

Aldosterone↗
PubMed1994

Response of atrial natriuretic factor to surgical pericardial drainage in patients with chronic pericardial effusion.

Previous studies have demonstrated the importance of atrial transmural pressure in the secretion of atrial natriuretic peptide. These studies have been performed in patients with pericardial effusion and hemodynamic compromise. The response of atrial natriuretic peptide to the drainage of chronic pericardial effusion without clinical evidence of tamponade is unknown. We studied 13 patients with chronic abundant pericardial effusion but without hemodynamic compromise. Blood samples for hormonal determinations were drawn before and after surgical pericardiocentesis. Right atrial pressure was measured during the procedure. Drainage induced a significant increase of atrial natriuretic peptide (from 12 +/- 3.9 to 105 +/- 22.8 pmol/l, P < 0.001, mean +/- S.E.M.), correlated with the fall in right atrial pressure (from 7.65 +/- 1.18 to 4.31 +/- 1.46 mmHg, P < 0.05, r = 0.68, P = 0.01). This increase was inversely correlated with the rise of mean blood pressure after surgery (from 84 +/- 2.37 to 100 +/- 5.3 mmHg, P < 0.05, r = 0.65, P < 0.02). Plasma renin activity decreased after drainage (from 8.12 +/- 2.57 to 3.27 +/- 0.65 ng/ml/h, P < 0.05). Surgery induced an increase of plasma levels of aldosterone (from 811 +/- 241 to 1199 +/- 249 pmol/l, P < 0.05), which were reduced after pericardiocentesis (371 +/- 102 pmol/l, P < 0.02). In patients with chronic abundant pericardial effusion, surgical pericardiocentesis induced a significant increase of atrial natriuretic peptide, correlated with a fall in right atrial pressure. The increase of atrial natriuretic peptide was similar than in patients with tamponade, despite a moderate fall in right atrial pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

[11 beta-Hydroxysteroid dehydrogenase (11-beta-OHSD): physiology and lack of action in pathology].

The 11 beta OHSD is an ubiquitous enzyme which inactivates cortisol to cortisone by transforming the hydroxyl group at the 11-carbon to a keto group. Therefore, it confers to mineralocorticoid receptors their selectivity toward their ligand and may constitute an important mechanism of regulation tissue-specific of the access of ligand toward its receptors. More widely the 11 beta OHSD would modulate glucocorticoid activity to their own receptor. There is no possibility to measure directly this enzyme and its deficiency is indirectly evaluated by enhancement of the quotient (THF + alpha THF)/THE after analysis of urinary steroid metabolites. Such enzymatic deficits may be congenital and are observed in childhood where they give an apparent mineralocorticoid excess (AME) syndrome (type 1). Sometimes acquired and reversible, they are due to licorice intoxication, hypothyroidism, chronic alcoholism and may be involved in the genesis of some cases of hypertension.

11-beta-Hydroxysteroid Dehydrogenases↗