Hyperreninemic Hypoaldosteronism Research Articles

Non-canonical Wnt signaling triggered by WNT2B drives adrenal aldosterone production.

The steroid hormone aldosterone, produced by the zona glomerulosa (zG) of the adrenal gland, is a master regulator of plasma electrolytes and blood pressure. While aldosterone control by the renin-angiotensin system is well understood, other key regulatory factors have remained elusive. Here, we replicated a prior association between a non-coding variant in WNT2B and an increased risk of primary aldosteronism, a prevalent and debilitating disease caused by excessive aldosterone production. We further show that in both mice and humans, WNT2B is expressed in the mesenchymal capsule surrounding the adrenal cortex, in close proximity to the zG. Global loss of Wnt2b in the mouse results in a dysmorphic and hypocellular zG, with impaired aldosterone production. Similarly, humans harboring WNT2B loss-of-function mutations develop a novel form of Familial Hyperreninemic Hypoaldosteronism, designated here as Type 4. Additionally, we demonstrate that WNT2B signals by activating the non-canonical Wnt/planar cell polarity pathway. Our findings identify WNT2B as a key regulator of zG function and aldosterone production with important clinical implications.

Loss of LGR4/GPR48 causes severe neonatal salt wasting due to disrupted WNT signaling altering adrenal zonation.

Disorders of isolated mineralocorticoid deficiency, which cause potentially life-threatening salt-wasting crisis early in life, have been associated with gene variants of aldosterone biosynthesis or resistance; however, in some patients no such variants are found. WNT/β-catenin signaling is crucial for differentiation and maintenance of the aldosterone-producing adrenal zona glomerulosa (zG). Herein, we describe a highly consanguineous family with multiple perinatal deaths and infants presenting at birth with failure to thrive, severe salt-wasting crises associated with isolated hypoaldosteronism, nail anomalies, short stature, and deafness. Whole exome sequencing revealed a homozygous splice variant in the R-SPONDIN receptor LGR4 gene (c.618-1G>C) regulating WNT signaling. The resulting transcripts affected protein function and stability and resulted in loss of Wnt/β-catenin signaling in vitro. The impact of LGR4 inactivation was analyzed by adrenal cortex-specific ablation of Lgr4, using Lgr4fl/fl mice mated with Sf1:Cre mice. Inactivation of Lgr4 within the adrenal cortex in the mouse model caused decreased WNT signaling, aberrant zonation with deficient zG, and reduced aldosterone production. Thus, human LGR4 mutations establish a direct link between LGR4 inactivation and decreased canonical WNT signaling, which results in abnormal zG differentiation and endocrine function. Therefore, variants in WNT signaling and its regulators should systematically be considered in familial hyperreninemic hypoaldosteronism.

OR04-2 WNT2B Deficiency Results in Hyperreninemic Hypoaldosteronism in Humans and Mice

Abstract Proper development and zonation of the adrenal cortex is intimately connected with its lifelong capacity to produce steroid hormones. Both adrenocortical development and homeostasis are mediated in part by paracrine WNT/β-catenin signaling, an essential pathway for zonal maintenance and aldosterone production. Patients harboring homozygous or compound heterozygous loss-of-function (LOF) mutations in the WNT ligand WNT2B present with congenital diarrhea and require parenteral nutrition. Despite evidence for euvolemia, WNT2B-null patients exhibit markedly elevated plasma renin levels with no corresponding increase in aldosterone, suggesting a primary adrenal defect in aldosterone synthesis. To test this hypothesis, we generated both global and conditional Wnt2b knockout mouse models. In the mouse adrenal, Wnt2b is expressed exclusively in the capsule, the outer compartment of mesenchymal cells that overlay and signal to the subcapsular zona glomerulosa (zG), the adrenocortical zone that harbors aldosterone-producing cells and critical long-term progenitor cells. Global loss of Wnt2b from early mouse development results in a near-complete absence of the histological zG. Moreover, Wnt2b-null mice exhibit significantly increased plasma renin but normal aldosterone levels compared to wild-type controls. These data suggest that WNT2B-null patients indeed have an adrenocortical phenotype caused by apparent zG hypofunction. To further define the mechanism(s) by which Wnt2b LOF leads to zG hypofunction, we temporally deleted Wnt2b in the adrenal capsule of adult mice. Wnt2b conditional knockout (cKO) adrenals exhibit a zG-restricted decrease in Wnt/β-catenin signaling as determined by decreased β-catenin activity and target gene expression. Moreover, Wnt2b cKO mice demonstrated a disorganized zG and disrupted adrenocortical zonation. To determine the contribution of WNT2B to aldosterone production, we administered a sodium-deficient diet to control and Wnt2b cKO mice to activate the renin-angiotensin-aldosterone system. Indeed, while control mice exhibited the expected increase in both plasma renin and aldosterone, Wnt2b cKO mice showed marked elevation of renin despite normal aldosterone compared to controls, consistent with hyperreninemic hypoaldosteronism. Together, our work supports a WNT2B-dependent mechanism for adrenal zG development and maintenance in mice and humans and provides relevant models to study the consequences of WNT2B deficiency within the zG. Presentation: Saturday, June 11, 2022 11:45 a.m. - 12:00 p.m.

CIRMI—a new term for a concept worthy of further exploration: a narrative review

Background and ObjectiveCritical illness-related corticosteroid insufficiency (CIRCI) describes hypothalamic-pituitary-axis impairment during critical illness associated with three major pathophysiological events; dysregulation of the hypothalamic-pituitary-axis, altered cortisol metabolism, and tissue corticosteroid resistance. Similar changes are evident with regard to mineralocorticoid dysfunction in critical illness. Hyperreninemic hypoaldosteronism describes a sub-population of critically ill patients with an impaired adrenal aldosterone response to increased levels of renin. In the light of the recent demonstration of significant mortality improvements associated with adjunctive glucocorticoid treatment in combination with fludrocortisone in septic shock, and the suggestion that angiotensin II is effective in treating vasodilatory shock, the clinical relevance of mineralocorticoid dysfunction in critical illness requires further exploration. This interpretative review considers hyperreninemic hypoaldosteronism, a concept worth re-examining in the light of the potential mortality benefit of mineralocorticoid supplementation in critical illness. We compare the pathophysiological and clinical characteristics of CIRCI and hyperreninemic hypoaldosteronism, two syndromes that represent corticosteroid and mineralocorticoid dysfunction in critical illness. We highlight gaps in the literature and give novel insights into the limitations of assessment, diagnosis and treatment.MethodsEnglish language abstracts and articles published before June 2021 were identified through PubMed and Google Scholar. Randomized trials, observational studies, basic sciences studies, systematic and narrative reviews were considered. Reference lists of articles were searched for further relevant material.Key Content and FindingsDifficulties are encountered in interpreting measures of gluco- and mineralo-corticoid activity in critical illness. Aldosterone levels, like cortisol, have been shown to be increased in sepsis and hemorrhagic shock. The finding of hyperreninemia and hyperaldosteronism with an aldosterone/plasma renin activity ratio below 2 should prompt consideration of hyperreninemic hypoaldosteronism, a finding, which likely signifies the loss of negative feedback control of the renin-angiotensin-aldosterone system.ConclusionsAs there is evidence to suggest that in acute critical illness, hyperreninemic hypoaldosteronism, is associated with poor outcomes, co-administration of hydrocortisone with fludrocortisone in patients with septic shock should be considered. In keeping with the concept of CIRCI, we suggest the term critical illness-related mineralocorticoid insufficiency as a more appropriate description of the impaired aldosterone response to increased levels of renin seen in this group of patients.

Mineralocorticoid Dysfunction during Critical Illness: A Review of the Evidence.

The recent demonstration of the significant reduction in mortality in patients with septic shock treated with adjunctive glucocorticoids combined with fludrocortisone and the effectiveness of angiotensin II in treating vasodilatory shock have renewed interest in the role of the mineralocorticoid axis in critical illness. Glucocorticoids have variable interactions at the mineralocorticoid receptor. Similarly, mineralocorticoid receptor-aldosterone interactions differ from mineralocorticoid receptor-glucocorticoid interactions and predicate receptor-ligand interactions that differ with respect to cellular effects. Hyperreninemic hypoaldosteronism or selective hypoaldosteronism, an impaired adrenal response to increasing renin levels, occurs in a subgroup of hemodynamically unstable critically ill patients. The suggestion is that there is a defect at the level of the adrenal zona glomerulosa associated with a high mortality rate that may represent an adaptive response aimed at increasing cortisol levels. Furthermore, cross-talk exists between angiotensin II and aldosterone, which needs to be considered when employing therapeutic strategies.

Sugar or salt? The relative roles of the glucocorticoid and mineralocorticoid axes in traumatic shock

Glucocorticoid deficiency (GD) has been proposed as a key contributor to shock states, but the presence and role of acute mineralocorticoid deficiency may be of equal or greater significance. We sought to analyze the incidence and degree of acute mineralocorticoid deficiency and GD in an animal model of severe hemorrhage and shock. Fifty-seven swine underwent 35% volume-controlled hemorrhage followed by aortic cross-clamping for 50 minutes to induce truncal ischemia-reperfusion. Protocol-guided resuscitation was performed. Laboratory analysis included cortisol, aldosterone, and plasma renin activity. The aldosterone-to-renin ratio (ARR) was calculated at each time point, and changes were correlated to markers of perfusion. Mean baseline cortisol levels were 5.8 μg/dL. Following hemorrhage, there was a significant increase in mean cortisol to 9.2 μg/dL (p < 0.001). After 1 hour of reperfusion, there was no change in mean cortisol levels (9.8 μg/dL, p = 0.12). Mean baseline aldosterone was 13.3 pg/mL. Aldosterone levels before cross-clamp removal increased significantly to 115.1 pg/mL (p < 0.001) and then rapidly declined to 49.2 pg/mL (p < 0.001) after 1 hour of reperfusion. Conversely, baseline plasma renin activity was 0.75 ng/mL per hour and increased significantly before cross-clamp removal (1.8) and at 1 hour (8.9, both p < 0.001). The ARR at baseline was 96.1 and increased to 113.5 (p = 0.68) before cross-clamp removal but significantly declined following 1 hour of reperfusion to 7.6 (p < 0.001). Overall, this represented a 93% reduction in mean ARR following reperfusion. The degree of aldosterone deficiency correlated with degree of systemic shock as measured by arterial base deficit (r = 0.47, p = 0.04), while cortisol showed no correlation. Hemorrhagic shock with ischemia-reperfusion injury resulted in only modest impact on the glucocorticoid axis, but major dysfunction of the mineralocorticoid axis and severe hyperreninemic hypoaldosteronism. The degree of aldosterone deficiency may provide prognostic information or offer potential targets for pharmacologic intervention. Diagnostic study, level III.

A Case of Myotonic Dystrophy with Electrolyte Imbalance

Type 1 myotonic dystrophy (DM1) is an autosomal-dominant inherited disorder with a multisystem involvement, caused by an abnormal expansion of the CTG sequence of the dystrophic myotonia protein kinase (DMPK) gene. DM1 is a variable multisystem disorder with muscular and nonmuscular abnormalities. Increasingly, endocrine abnormalities, such as gonadal, pancreatic, and adrenal dysfunction are being reported. But, Electrolytes imbalance is a very rare condition in patients with DM1 yet. Herein we present a 42-yr-old Korean male of DM1 with abnormally elevated serum sodium and potassium. The patient had minimum volume of maximally concentrated urine without water loss. It was only cured by normal saline hydration. The cause of hypernatremia was considered by primary hypodipsia. Hyperkalemic conditions such as renal failure, pseudohyperkalemia, cortisol deficiency and hyperkalemic periodic paralysis were excluded. Further endocrine evaluation suggested selective hyperreninemic hypoaldosteronism as a cause of hyperkalemia.

高カルシウム尿症と一過性の腎性低尿酸血症と活性型ビタミンＤ高値を合併したＨｙｐｅｒｒｅｎｉｎｅｍｉｃ ｈｙｐｏａｌｄｏｓｔｅｒｏｎｉｓｍの２か月男児例

高カルシウム尿症と一過性の腎性低尿酸血症と活性型ビタミンＤ高値を合併したＨｙｐｅｒｒｅｎｉｎｅｍｉｃ ｈｙｐｏａｌｄｏｓｔｅｒｏｎｉｓｍの２か月男児例

Endocrine Response After Severe Subarachnoid Hemorrhage Related to Sodium and Blood Volume Regulation

Hyponatremia is often associated with, and worsens, the prognosis of severe aneurysmal subarachnoid hemorrhage (SAH). Several possible endocrine perturbations of variable severity and variable sodium and water intake have been described in SAH. However, a comprehensive study of the different hormonal systems involved in sodium and water homeostasis and circulating blood volume modifications is still needed. Our aim was to assess water and sodium regulation after severe SAH by investigating blood volume and several hormonal regulatory systems in the context of hyponatremia prevention by controlled sodium intake. Nineteen mechanically ventilated patients with severe SAH, were prospectively studied. Replacement of sodium was at least 4.5 mmol x kg(-1) x d(-1) and adjusted on natriuresis. Hormones involved in electrolyte and water homeostasis: vasopressin, renin, angiotensin, aldosterone, and natriuretic peptides were assessed every 3 days for 12 days. Red blood cell volume was measured by the isotopic method (technetium-labeled red blood cells), in the first 48 h after admission and at day 7. Cardiac function was assessed using electrocardiogram, transthoracic echocardiography, and troponin Ic (cTnI). Outcome was assessed at 3 mo. After SAH onset, hyponatremia, but not decreased circulating blood volume, was prevented by high sodium and water infusion adapted to renal excretion. The hormonal profiles were characterized by an increase in renin, angiotensin II, natriuretic peptide concentrations associated with increased troponin Ic, stable low levels of vasopressin, and the absence of increased aldosterone concentrations. There were no correlations between hormone concentrations and natriuresis. After severe SAH, in the context of multiple clinical interventions, increased natriuresis and low blood volume are consistent with cerebral salt wasting syndrome, probably related to the sequence of severe SAH, highly increased sympathetic tone, hyperreninemic hypoaldosteronism syndrome, and increased natriuretic peptides release.

A NovelCYP11B2Gene Mutation in an Asian Family with Aldosterone Synthase Deficiency

Three siblings of Pakistani origin presented neonatally with isolated hyperreninemic hypoaldosteronism and were well controlled on fludrocortisone therapy during childhood and adolescence. These individuals were reevaluated as adults after fludrocortisone withdrawal to investigate the biochemical and molecular basis of their disorder. When reassessed off fludrocortisone treatment, hyperreninemic hypoaldosteronism was confirmed in all subjects but with significant hyperkalemia in only one case. Profiling of urinary steroid metabolites showed a biochemical pattern (elevated tetrahydrocorticosterone to 18-hydroxytetrahydro-11-dehydrocorticosterone ratio but normal 18-hydroxytetrahydro-11-dehydrocorticosterone to tetrahydroaldosterone ratio) consistent with partial type 1 aldosterone synthase deficiency. Sequencing of the CYP11B2 gene showed that affected subjects were homozygous for a single nucleotide substitution (T925C) in exon 5, corresponding to a serine to proline mutation (S308P) in the predicted protein, with unaffected family members being heterozygous. Consistent with structural modeling showing that the mutated residue is located within the alpha-helix I, close to the hemebinding, active site of the enzyme, functional characterization of the S308P mutant protein in vitro showed complete loss of enzyme activity. However, administration of dexamethasone further reduced levels of circulating aldosterone and its urinary metabolites in affected subjects, suggesting that some mineralocorticoid biosynthesis occurs in vivo. We have identified the first CYP11B2 gene defect in a family of Asian origin, associated with a type 1 aldosterone synthase deficiency phenotype. Preservation of some aldosterone production suggests either residual mutant CYP11B2 enzyme activity in vivo or mineralocorticoid biosynthesis via an alternative pathway.

Hyperreninemic hypoaldosteronism syndrome, plasma concentrations of interleukin-6 and outcome in critically ill patients with liver cirrhosis

To investigate the relation between the adrenal production of gluco- and mineralocorticoids, the inflammatory status and the outcome in critically ill patients with liver cirrhosis. Prospective descriptive study. Medical intensive care unit (ICU) in a university hospital. Fifty consecutive patients with liver cirrhosis. A corticotropin stimulation test within 12h following ICU admission. Plasma cortisol concentration was measured before and after the test. Renin and aldosterone concentrations, as well as interleukin-6 (IL-6) level to assess the pro-inflammatory status, were measured only before the test. Impaired adrenal function was defined as cortisol response to the test less than 9microg/dl. Hyperreninemic hypoaldosteronism syndrome was defined as basal renin over aldosterone ratio (RRA) higher than 2. Forty-one (82%) patients had impaired adrenal function, and 26 patients (52%) presented with RRA > 2. Patients with RRA > 2 exhibited greater disease severity and organ dysfunction scores at baseline, higher levels of serum renin and IL-6, and a greater ICU mortality rate, but risk-adjusted mortality rates were not different between the two groups. Renin and IL-6 plasma concentrations were positively correlated. Finally, in a Cox regression analysis, independent predictors of 30-day mortality were hyperreninemic hypoaldosteronism syndrome, IL-6 higher than 400pg/ml and severe renal failure. Adrenal dysfunction was common in critically ill cirrhotic patients. Hyperreninemic hypoaldosteronism syndrome was related to a greater pro-inflammatory status and degree of acute organ failure, and was independently associated with a worse prognosis.

Aldosterone synthase deficiency and related disorders

Aldosterone’s main actions are to regulate intravascular volume and serum electrolytes by controlling sodium absorbtion and potassium excretion in the distal nephron. Inherited defects in aldosterone biosynthesis thus cause hypovolemia, hyponatremia and hyperkalemia. Defective aldosterone biosynthesis may be caused by congenital adrenal hyperplasia due to 21-hydroxylase (CYP21) deficiency, in which case cortisol biosynthesis is also affected, or as an isolated defect termed aldosterone synthase (corticosterone methyloxidase, CYP11B2) deficiency. Many mutations have been documented in each of these genes; in general enzymatic activity must be reduced to <1% of normal for aldosterone biosynthesis to be impaired. An additional form of familial hyperreninemic hypoaldosteronism has been described that is not due to mutations in CYP11B2, but its etiology remains to be elucidated.

Hyperreninemic hypoaldosteronism: a possible etiological factor of septic shock-induced acute renal failure.

Hyperreninemic hypoaldosteronism has been described in critically ill patients. The present study investigated the plasma aldosterone concentration (PAC) in septic shock patients and its relationship with clinical course. Prospective descriptive study in a medical intensive care unit (ICU) of a university hospital. Forty-six consecutive patients with septic shock as defined by the ACCP/SCCM criteria. A corticotropin stimulation test, followed by treatment with low doses of hydrocortisone and fludrocortisone. Plasma renin activity, PAC, and cortisol levels were measured before and after the test. PAC measurements were repeated for 1 week. Relevant clinical and laboratory variables were recorded for ICU stay. Patients were divided into two groups according to PAC/renin activity ratio: above 2 (n=24 patients) and below 2 n=22). Patients with PAC/renin activity less than 2 had higher total volume of infused fluid, serum creatinine level, and fractional excretion of sodium values; aldosterone and serum creatinine were negatively correlated. Hypoaldosteronism was reversible within 1 week. Duration of ICU stay (p=0.0026) and the need for renal replacement therapy (p=0.0021) were greater in the group with PAC/renin less than 2. Transient hyperreninemic hypoaldosteronism is common in patients with septic shock. These abnormal aldosterone levels are associated with greater sodium and fluid depletion and are followed by enhanced incidence of acute renal failure requiring renal replacement therapy and prolonged length of stay in ICU.

The endocrine response to critical illness

The endocrine response to stress is complex. Elevations in the serum concentrations of the "classic" stress hormones, epinephrine and cortisol, occur following many kinds of physiologic challenge and are accompanied by elevations in corticotropin, GH, and glucagon levels. These changes are probably responsible for the hyperglycemia and hypercatabolism common to most critical illness. If volume depletion is present, vasopressin, renin, and aldosterone secretion are also likely to be stimulated. These hormones, if present in excess, may produce fluid retention and hyponatremia. In some critically ill patients, there is a dissociation of renin and aldosterone production called hyperreninemic hypoaldosteronism, but the clinical importance of this syndrome is poorly understood. Thyroid hormone metabolism is commonly affected by critical illness, which results in characteristic abnormalities of thyroid function testing known as the euthyroid sick syndrome. The reproductive axis is exquisitely sensitive to physiologic stress; hypogonadotropic hypogonadism is a common finding in critical illness. The ongoing challenge to the clinician is to determine whether seemingly abnormal hormone measurements in critically ill patients reflect an appropriate homeostatic response to severe illness or, instead, whether they denote an independent metabolic disorder that might actually cause or contribute to the patient's unstable condition. In view of the exceedingly complex (and poorly understood) interactions involved in the human response to a severe illness, a thoughtful approach to the whole patient is essential and far preferable to indiscriminate hormone testing. Such testing, at best, may be uninterpretable in light of the clinical circumstances or, at worst, may lead to therapeutic misadventures.

Paracrine regulation of the renin-aldosterone system

A number of clinical states have been described where there are derangements or discrepancies between renin-angiotensin and aldosterone secretion. We have studied the potential effect of some cytokines or growth factors (peptide regulatory factors) on this system in vitro. Both tumor necrosis factor/cachectin and interleukin I are potent regulators acting as renin secretogogues and inhibitors of aldosterone synthesis. These actions are mediated by prostaglandin cyclooxygenase products and their actions mimic the syndrome of hyperreninemic hypoaldosteronism in critical illness. Insulin and insulin-like growth factor I are also renin secretogogues in vitro However in a diabetic model (streptozotocin rat), there is resistance to both agonists as well as enhanced feedback suppression to angiotensin. A third peptide, transforming growth factor (TGFβ) has even more complex actions, acting as a secretogogue at low doses (10 −12M) but inhibiting renin at higher doses. TGFβ production is increased in the diabetic state so that this peptide as well as the insulin family may be involved in hyporeninemic hypoaldosteronism.

Dose effect of adrenocorticotropin on aldosterone and cortisol biosynthesis in cultured bovine adrenal glomerulosa cells: in vitro correlate of hyperreninemic hypoaldosteronism.

In some critically ill patients, aldosterone secretion is diminished despite hyperreninemia. These same patients demonstrate appropriately elevated plasma ACTH and cortisol levels. In addition, infusion of ACTH or angiotensin-II (AII) fails to elicit the normal aldosterone response, implying that the defect is at the level of the zona glomerulosa (ZG) cell. To test the hypothesis that elevated ACTH levels induce this defect, Percoll-purified bovine ZG cells were plated in serum-free defined medium and cultured for 5 days. On days 1-4, cells were exposed to various concentrations of ACTH for 1 h. On the fifth day of culture, half of the wells pretreated with ACTH were treated for 1 h with AII (10(-7) M); the other half of the wells received another dose of ACTH for 1 h. Additionally, cells were exposed to daily 1-h pulses of AII (10(-7) M) alone or in combination with ACTH (10(-8) M) for 5 days. Acutely dispersed bovine ZG cells showed dose-dependent increases in aldosterone when incubated with ACTH, potassium, or AII, with minimal cortisol production. Acutely dispersed bovine fasciculata cells produced no aldosterone, but demonstrated a dose-dependent cortisol response to ACTH and AII, but not potassium. On day 1 of culture, the ZG cells demonstrated a significant (P less than 0.001 in all cases) dose-related increase in aldosterone secretion in response to ACTH. However, continued daily pulsation with ACTH resulted in a dose-dependent decrease in aldosterone secretion, with a concomitant dose- and time-related rise in cortisol production. Indeed, ACTH-induced cortisol production in ZG became similar to ACTH-induced cortisol production in zona fasciculata cells. The addition of AII to the daily ACTH pulse did not significantly alter the aldosterone or cortisol response patterns to ACTH alone. In contrast, ZG cells treated with AII alone for 5 days showed a minimal change in cortisol production and no reduction in aldosterone production until day 4. Northern blot analysis of total RNA isolated from ZG cells pulsed with ACTH for 5 days demonstrated a parallel dose-dependent increase in 17 alpha-hydroxylase mRNA, which did not occur in cells pulsed with AII alone. These in vitro results suggest that elevated ACTH levels over time induce 17 alpha-hydroxylase activity in ZG cells, thereby shifting steroid biosynthesis from an aldosterone-producing to a cortisol-producing pathway. It is likely that the chronically elevated ACTH levels in critically ill patients induce a similar change in ZG cell biosynthesis, resulting in their hyperreninemic hypoaldosterone state.

Cytokines and the hypothalamic-pituitary-adrenal axis

After administration of the cytokines interleukin 1 (IL1), tumor necrosis factor (TNF), interleukin 2 and interleukin 6 to laboratory animals or humans, plasma levels of glucocorticoids are elevated. This effect is mediated by activation of the hypothalamic-pituitary unit. IL1 and TNF inhibit aldosterone production by rat adrenocortical cells in vitro and stimulate renin release by rat renal cortical cells. Administration of IL1 or TNF in rats suppresses hypothalamic-pituitary-thyroid function, whereas IL1 acts at the level of the brain and the gonads to interfere with gonadotropin and sex steroid secretion. During stimulation of the immune system (e.g. during infectious diseases), peculiar alterations in hormone secretion occur (hypercortisolism, hyperreninemic hypoaldosteronism, euthyroid sick syndrome, hypogonadism). The role of cytokines in these alterations remains to be established.

Acquired Partial Corticosterone Methyl Oxidase Type II Defect in Diabetes Mellitus: Case of Hyperreninemic Hypoaldosteronism

The aim of this study was to investigate the pathogenesis of hypoaldosteronism in diabetes. Endogenous elevation of plasma renin activity and exogenous corticotropin were used to study steroidogenesis. Observations were made over 12 yr on the evolution and treatment of hyperkalemia in a diabetic subject. In 1977, potassium, baseline cortisol, aldosterone, and renin activity were normal; renin activity increased normally with posture; and cortisol responded normally to ACTH infusion. Nine yr later, persistent hyperkalemia was documented. Upright renin activity was elevated to 5.26 ng.L-1.s-1, with concomitant elevation of 18-hydroxycorticosterone (18-OHB) and a low-normal aldosterone level. One hour after administration of 0.25 mg i.m. cosyntropin, cortisol increased normally, aldosterone increased from 220 to 360 pM, and 18-OHB increased from 3700 to 4800 pM. During treatment with fludrocortisone, fludrocortisone with furosemide, and furosemide alone, improvement of hyperkalemia was noted. Endogenous hyperreninemia and basal elevations of 18-OHB, accompanied by limited aldosterone responsiveness to renin and ACTH, suggest the presence of a partial corticosterone methyl oxidase type II defect. Evolution of hyperkalemia between 1977 and 1986 suggests this defect was acquired.

Effects of Prolonged Cyclosporine-A Treatment on the Morphology and Function of Rat Adrenal Cortex

The effects of prolonged (30 day) treatment with daily therapeutical doses of cyclosporine A (CSA) (20 mg/kg) on the function and morphology of adrenal cortex were studied in adult male rats. CSA-treated animals developed a notable hypertension, along with a striking rise in PRA, which was not coupled with significant changes in the plasma concentrations of aldosterone and corticosterone (hyperreninemic hypoaldosteronism). Morphometry showed that zona glomerulosa (ZG) and zona fasciculata, and their parenchymal cells were atrophic. Isolated capsular (ZG) and inner (zona fasciculata/reticularis) cells displayed reduced basal and stimulated secretory responses. However, while the response of ZG cells to angiotensin II was almost completely suppressed (96%), basal steroid secretion of isolated cells, as well as the aldosterone and corticosterone response of ZG cells to potassium and ACTH, and corticosterone production of inner cells in response to ACTH were decreased by only about 30-40%. The hypothesis is advanced that CSA exerts a dual effect on rat adrenal cortex: 1) a general inhibitory effect on the growth and steroidogenic capacity of adrenocortical cells, which manifests itself only after very prolonged treatment and may be caused by an impairment of protein synthesis; and 2) an acute effect involving the specific blockade of the angiotensin-II-induced stimulation of the secretory activity of ZG cells.

Isolated hyperreninemic hypoaldosteronism due to carcinoma metastatic to the adrenal gland

Isolated hyperreninemic hypoaldosteronism due to carcinoma metastatic to the adrenal gland