Phase 1B study of the safety and tolerability of the mineralocorticoid fludrocortisone acetate in patients with geographical atrophy

Objective

To evaluate the safety and tolerability of a mineralocorticoid, in a single-dose intravitreal (IVT) injection of 1 mg/0.1 mL and 2 mg/0.1 mL fludrocortisone acetate (FCA) in subjects with geographical atrophy (GA) secondary to age-related macular degeneration.

Methods and Analysis

This phase 1b study was a two-part dose-escalation prospective study. Part 1 involved a single participant treated with 1 mg/0.1 mL and monitored up to 28 days before being reviewed by a safety review committee. Two subsequent participants were then dosed with the same dose. Part 2 involved a single participant dosed with 2 mg/0.1 mL and monitored up to 28 days when a further five participants were dosed. All participants were followed up for 6 months after baseline.

A full ophthalmic assessment was performed at study visits which included GA area, best-corrected visual acuity (BCVA), low-luminance BCVA (LL-BCVA) and intraocular pressure (IOP). Adverse events (AEs) were reported from the first dose of FCA until the end-of-study visit.

Results

There were no serious AEs (ocular or systemic) observed with IVT FCA at either 1 mg/0.1 mL or 2 mg/0.1 mL among nine participants. There was no evidence of increased IOP or cataract development.

Neither BCVA or LL-BCVA changed significantly in the study-eye over the follow-up period (p=0.28 and 0.38, respectively). Mean GA area increased in the study (0.5 mm², p=0.003) and fellow-eyes (0.62 mm², p=0.02) over 6 months. Differences between eyes were not significant (p=0.64), and at the lower end of population norms.

Conclusion

IVT FCA is clinically safe and well tolerated and did not increase IOP.

Stability Studies of Fludrocortisone Acetate Capsules and Fludrocortisone Acetate Titrated Powders (Powder Triturates)

Fludrocortisone acetate is a drug used to treat adrenal insufficiencies which can be prescribed to hospitalized or ambulatory pediatric patients at dosages not commercially available. For these patients, 10-µg fludrocortisone capsules are currently compounded from a pre-compounded titrated powder (powder triturate). Fludrocortisone stability studies were carried out to ensure a valid beyond-use date. First, a stability-indicating fludrocortisone acetate dosing method was validated. Then fludrocortisone acetate 10-µg capsules and 1% fludrocortisone acetate titrated powders (powder triturates) were realized. Finally, stability studies were performed. The fludrocortisone acetate titrated powders (powder triturates) were stable for one year at controlled ambient temperature and protected from light, whereas 10-µg fludrocortisone acetate capsules were stable for six months. One year after, even if the fludrocortisone content remained conformed, an increase in product degradation was noted. Our work allowed us to determine a six-month beyond-use date for fludrocortisone acetate titrated powder (powder triturate) with the three most commonly used excipients for capsule compounding. We also confirmed the sixmonth theoretical stability for capsules.

What factors have impact on glucocorticoid replacement in adrenal insufficiency: a real-life study

PURPOSE

The impact of patient's characteristics on glucocorticoid (GC) replacement therapy in adrenal insufficiency (AI) is poorly evaluated. Aims of this study were to assess the influence of sex and body weight on GC dosing and to describe the choice of GC in AI of different etiologies.

METHODS

We retrospectively evaluated hydrocortisone (HC) equivalent total daily dose (HC-TDD) and per-kg-daily dose (HC-KDD) in 203 patients (104 primary AI [pAI], 99 secondary AI [sAI]) followed up for ≥ 12 months. They were treated with HC, modified-release HC (MRHC) or cortisone acetate (CA) and fludrocortisone acetate (FCA) in pAI.

RESULTS

At baseline, CA was preferred both in pAI and sAI; at last visit, MRHC was most used in pAI (49%) and CA in sAI (73.7%). Comparing the last visit with baseline, in pAI, HC-TDD and HC-KDD were significantly lower (p = 0.04 and p = 0.006, respectively), while FCA doses increased during follow-up (p = 0.02). The reduction of HC-TDD and HC-KDD was particularly relevant for pAI women (p = 0.04 and p = 0.002, respectively). In sAI patients, no change of HC-KDD and HC-TDD was observed, and we found a correlation between weight and HC-TDD in males (r 0.35, p = 0.02).

CONCLUSIONS

Our real-life study demonstrated the influence of etiology of AI on the type of GC used, a weight-based tailoring in sAI, a likely overdosage of GC treatment in pAI women at the start of treatment and the possibility to successfully increase FCA avoiding GC over-treatment. These observations could inform the usual clinical practice.

Congenital Adrenal Hyperplasia with Salt Wasting Crisis: A Case Report

Congenital Adrenal Hyperplasia is a group of autosomal recessive disorders due to deficiencies of enzymes involved in steroidogenesis. The most common form is a 21-hydroxylase deficiency which can be classical or non-classical. The severe form also called Classical Congenital Adrenal Hyperplasia is usually detected after birth to infant period. If Congenital Adrenal Hyperplasia is not diagnosed and treated early, neonates are susceptible to sudden death in the early weeks of life. We report a case of thirty-five days male with a salt-wasting variant of congenital adrenal hyperplasia. The diagnosis was based on an elevated level of 17-hydroxyprogesterone. He was managed and life long oral Prednisolone and Fludrocortisone were prescribed.

Azione di un Nuovo Ormone Maschile Sull'Adenocarcinoma Mammario Murino Coltivato in Vitro

The action of a new male hormone, the flusterone (9 α fluorine-11β hydroxi-17 methyltestosterone), has been studied on « in vitro » cultures of spontaneous mammary adenocarcinoma of the C3H mouse strain, and compared with that exerted by methyltestosterone and testosterone at the same concentrations. The three tested hormones showed a growth inhibiting action at the concentration of 100 γ/ml, slighter for methyltestosterone and testosterone and rather more marked for flusterone.

Hyponatremia in an Elderly Patient due to Isolated Hypoaldosteronism Occurring after Licorice Withdrawal

Hyponatremia is one of the most common electrolyte disorders encountered in the elderly. We present the case of an 81-year-old man who developed hyponatremia due to isolated hypoaldosteronism occurring after licorice withdrawal. He had severe hypokalemia with hypertension and was diagnosed with pseudoaldosteronism. He had been taking a very small dose of licorice as a mouth refresher since his early adulthood. Five months after licorice withdrawal, he developed hypovolemic hyponatremia, which was resolved with administration of fludrocortisone acetate. Our experience with this case suggests that isolated hypoaldosteronism occurring after licorice withdrawal should be considered as a potential cause of hyponatremia in elderly patients.

Corticosteroid Fludrocortisone Acetate Targets Multiple End Points in Zebrafish (Danio rerio) at Low Concentrations

Synthetic corticosteroids may pose an environmental risk to fish. Here, we describe multiend point responses of adult zebrafish (8 months old) upon 21-day exposure to a commonly prescribed corticosteroid, fludrocortisone acetate (FLU), at concentrations between 0.006 and 42 μg/L. No remarkable reproductive impacts were observed, while physiological effects, including plasma glucose level and blood leukocyte numbers were significant altered even at 42 ng/L. Ovary parameters and transcriptional analysis of hypothalamic-pituitary-gonadal-liver axis revealed negligible effects. Significant alterations of the circadian rhythm network were observed in the zebrafish brain. Transcripts of several biomarker genes, including per1a and nr1d1, displayed strong transcriptional changes, which occurred at environmental relevant concentrations of 6 and 42 ng/L FLU. Importantly, the development and behavior of F1 embryos were significant changed. Heartbeat, hatching success and swimming behavior of F1 embryos were all increased even at 6 and 42 ng/L. All effects were further confirmed by exposure of eleuthero-embryos. Significant transcriptional changes of biomarker genes involved in gluconeogenesis, immune response and circadian rhythm in eleuthero-embryos confirmed the observations in adult fish. Hatching success, heartbeat, and swimming activity were increased at 81 ng/L and higher, as with F1 embryos. These results provide novel insights into the understanding of potential environmental risks of corticosteroids.

Effect of γ-cyclodextrin on the in vitro skin permeation of a steroidal drug from nanoemulsions: impact of experimental setup

Numerous reports on the enhancement effect of cyclodextrins (CDs) on the skin permeation of dermally applied drugs exist, the majority of which is based on in vitro diffusion cell studies. The specific experimental setup of such studies may skew the obtained results, which is rarely discussed in the context of CD studies. Thus, the aim of this work was to conduct a systematic in vitro investigation of the permeation enhancement potential of γ-CD on a steroidal drug from a nanoemulsion. The role of critical diffusion cell parameters such as the dose of application, occlusive conditions, the nature of the receptor medium and the skin thickness were investigated. The results showed that significantly enhanced skin permeation rates of fludrocortisone acetate were indeed caused by 1% (w/w) of γ-CD at both finite and infinite dose conditions. At 0.5% (w/w) of γ-CD, significant enhancement was only achieved at infinite dose application. Additional in vitro tape stripping experiments confirmed these tendencies, but the observed effects did not reach statistical significance. It may be concluded that the full permeation enhancement potential of the CD as observed in the Franz-cell setup can only be realised at infinite dose conditions while preserving the formulation structure.

Development of sucrose stearate-based nanoemulsions and optimisation through γ-cyclodextrin

Nanoemulsions aimed at dermal drug delivery are usually stabilised by natural lecithins. However, lecithin has a high tendency towards self-aggregation and is prone to chemical degradation. Therefore, the aim of this study was to develop nanoemulsions with improved structure and long-term stability by employing a natural sucrose ester mixture as sole surfactant. A thorough comparison between the novel sucrose stearate-based nanoemulsions and corresponding lecithin-based nanoemulsions revealed that the sucrose ester is superior in terms of emulsifying efficiency, droplet formation as well as physical and chemical stability. The novel formulations exhibited a remarkably homogeneous structure in cryo TEM investigations, as opposed to the variable structure observed for lecithin-based systems. The in vitro skin permeation rates of lipophilic drugs from sucrose stearate nanoemulsions were comparable to those obtained with their lecithin-based counterparts. Furthermore, it was observed that addition of γ-cyclodextrin led to enhanced skin permeation of the steroidal drug fludrocortisone acetate from 9.99±0.46 to 55.10±3.67 μg cm(-2) after 24 h in the case of sucrose stearate-based systems and from 9.98±0.64 to 98.62±24.89 μg cm(-2) after 24 h in the case of lecithin-based systems. This enhancement effect was significantly stronger in formulations based on lecithin (P<0.05), which indicates that synergistic mechanisms between the surfactant and the cyclodextrin are involved. Cryo TEM images suggest that the cyclodextrin is incorporated into the interfacial film, which might alter drug release rates and improve the droplet microstructure.

[Increased urinary sodium excretion in the early phase of aneurysmal subarachnoid hemorrhage as a predictor of cerebral salt wasting syndrome]

Cerebral salt wasting syndrome (CSWS) in patients with aneurysmal subarachnoid hemorrhage (SAH) is considered to correlate with delayed ischemic neurological deficits (DIND) induced by cerebral vasospasm; however, its exact mechanism is still not well-known. The purpose of the present study is to evaluate the relationship between hyponatremia caused by CSWS and the increase of the urinary sodium excretion in early phase following SAH. Fifty-four patients with SAH were divided into 2 groups, normonatremia group and hyponatremia group which suffered hyponatremia after SAH. The hyponatremia group comprise 14 patients (26%) in whom the hyponatremia developed of the SAH. In this group, the serum level of sodium significantly decreased 7 days after SAH and then gradually normalised. Further, excretion of sodium in the urine tended to increase 3 days after SAH and significantly increased 7 days after SAH. In conclusion, the increased urinary sodium excretion in the early phase of SAH would serve as a predictive factor for CSWS after SAH. We consider that it is important to start sodium and fluid supplementation and inhibit natriuresis by fludrocortisone acetate administration before hyponatremia occurs in order to prevention delayed ischemic neurological deficits in SAH patients.

[Synthetic mineralocorticoid]

Fludrocortisone acetate (Florinef) is a synthetic steroid with a potent mineralocorticoid action, and used for treatment of Addison's disease and salt losing form of congenital adrenal hyperplasia. It is also used for severe hypotension to restore adequate plasma volume. Caution is necessary for possible side effects of hypernatremia, hypokalemia, hyperglycemia and congestive heart failure when used chronically. A synthetic steroid which selectively binds and activates renal MR-LBD but not GR, or non-epithelial MR, although not found at present, may be a promising mineralocorticoids to be used in the above disorders.

Effect of fludrocortisone acetate on reducing serum potassium levels in patients with end-stage renal disease undergoing haemodialysis

BACKGROUND

Hyperkalaemia is a commonly encountered problem in dialysis patients with end-stage renal disease (ESRD). The aim of the present study was to assess the effect of fludrocortisone acetate (FCA) on reducing serum potassium levels in haemodialysis (HD) patients with hyperkalaemia.

METHODS

Prospectively, 21 HD patients with hyperkalaemia were enrolled in this study. Patients were divided into two groups, including FCA (0.1 mg/d, n = 13) administration or no treatment (control, n = 8) for 10 months. No changes in dialysis or drug regimens were made during this period. Result. There were no significant differences in the baseline characteristics and biochemical parameters between the two groups (FCA therapy and control). At 10-months after FCA therapy, serum potassium levels were not significantly different between the treatment and control groups [median value (range): 5.2 (4.4-6.0) vs 5.8 (4.8-6.3) mEq/l, P = 0.121]. However, using the Wilcoxon signed ranks test, serum potassium levels were significantly lower at the end of the 10 month time period after FCA therapy compared with serum potassium levels of the pre-treatment period [5.2 (4.4-6.0) vs 6.1 (5.3-6.8), P = 0.01]. The biochemical values, including sodium, chloride, protein, albumin, blood nitrogen, creatinine, interdialytic weight change and blood pressure, did not show significant difference in comparisons between the two groups and pre-and post-FCA therapy period.

CONCLUSIONS

FCA therapy appears to slightly decrease serum potassium value in hyperkalaemic HD patients. However, these results are insufficient to explain the effectiveness of FCA. Therefore, potentially large-scale studies with increased dose concentrations are needed to minimize the positive potassium balance in hyperkalaemic HD patients.

Primary aldosteronism: diagnostic and treatment strategies

Primary aldosteronism is caused by bilateral idiopathic hyperplasia in approximately two-thirds of cases and aldosterone-producing adenoma in one-third. Most patients with primary aldosteronism are normokalemic. In the clinical setting of normokalemic hypertension, patients who have resistant hypertension and hypertensive patients with a family history atypical for polygenic hypertension should be tested for primary aldosteronism. The ratio of plasma aldosterone concentration to plasma renin activity has been generally accepted as a first-line case-finding test. If a patient has an increased ratio, autonomous aldosterone production must be confirmed with an aldosterone suppression test. Once primary aldosteronism is confirmed, the subtype needs to be determined to guide treatment. The initial test in subtype evaluation is CT imaging of the adrenal glands. If surgical treatment is considered, adrenal vein sampling is the most accurate method for distinguishing between unilateral and bilateral adrenal aldosterone production. Optimal treatment for aldosterone-producing adenoma or unilateral hyperplasia is unilateral laparoscopic adrenalectomy. The idiopathic bilateral hyperplasia and glucocorticoid-remediable aldosteronism subtypes should be treated pharmacologically. All patients treated pharmacologically should receive a mineralocorticoid receptor antagonist, a drug type that has been shown to block the toxic effects of aldosterone on nonepithelial tissues.

Alternative therapies in antibiotic-resistant infection

CASE REPORT

A 24-year-old woman suffering from post-influenza otitis media infection was initially treated with several series of a steroid (Elocon) and a combination of steroids and antibiotics (Atecortin, Dicortineff) without significant medical benefit. The isolated bacterial strains were identified as Staphylococcus homis and Staphylococcus epidermidis. Specific phage therapy applied sequentially over a period of three weeks resulted only in a partial reduction in inflammation and limited improvement in overall health condition. Oral application of lactoferrin (LF; 50-mg daily oral doses for seven days with two-week intervals) led to a complete clearance of both bacterial strains and full recovery of the patient. The recovery was associated with increased myelopoiesis and a sustained elevation of serum endogenous LF. In conclusion, specific bacteriophage therapy combined with the administration of lactoferrin proved to be effective in the treatment of antibiotic-resistant external ear infection.

Urinary Prostasin

Prostasin is a serine peptidase hypothesized to regulate epithelial sodium channel (ENaC) activity in animals or on in vitro cultured cells. We investigated whether urinary prostasin may be a candidate marker of ENaC activation in humans. We studied 10 healthy volunteers and 8 hypertensive patients with raised aldosterone-to-renin ratio before and after spironolactone or saline/Florinef suppression test, respectively. Four healthy subjects were also studied before and after saline. Urinary prostasin was evaluated by SDS-PAGE, 2D maps, and Western blotting. Every sample of normotensive individuals was compared with the corresponding sample of urine collected after spironolactone or saline; every sample of hypertensive patients was compared with the corresponding sample of urine collected after saline or Florinef. Prostasin was detectable in all subjects regardless of gender, dietary sodium intake, and spironolactone treatment. Spironolactone (100 mg) increased urinary Na+/K+ ratio and decreased urinary prostasin in normotensives in whom the renin/aldosterone axis was activated by a low Na+ intake, but it was ineffective in individuals with high Na+ intake. Saline infusion also reduced prostasin in normotensive subjects. In contrast, prostasin paradoxically increased in urine of patients affected by primary aldosteronism after volume expansion. By 2D immunoblotting, several protein isoforms were observed, some of them being overexpressed after inhibition tests in patients with primary aldosteronism. In addition to a "basal" aliquot of prostasin, constitutively released in human urine regardless of sodium balance and aldosterone activation, there exists a second "aldosterone-responsive" aliquot modulated by Na+ intake and potentially suitable as candidate marker of ENaC activation.

[The effect of fluorine substituent on radiochemical stability of some steroid and azole derivatives]

Radiochemical stability of three fluorine containing therapeutic substances: dexamethasone, fludrocortisone acetate (steroid derivatives) and fluconazole (azole derivative) has been studied. The compounds in the solid phase were exposed to ionising radiation in the form of electron beam using doses of 20-400 kGy. The inital and irradiated compounds were subjected to comparative analyses by organoleptic, spectrophotometric (UV and IR) and chromatographic (TLC and HPLC) methods. For all compounds studied the irradiation was found to lead to a decrease in the active substance content (HPLC), appearance of radiolysis products (TLC), changes in the physical and chemical properties such as colour (fluconazole), formation of agglomerates (dexamethasone), decrease (dexamethasone, fludrocortisone acetate) or increase in UV absorption (fluconazole). The two steroid derivatives were found resistant to ionising radiation at doses of 25-50 kGy and can be sterilised by radiation, whereas fluconazole was too sensitive to electron beam irradiation and should be sterilised by other methods. The results were compared with those of earlier studies on radiation sterilisation of other steroid derivatives. An interesting conclusion is that the presence of the fluorine atom in the molecule of fludrocortisone acetate has no significant effect on its radiochemical stability when compared with that of hydrocortisone acetate--the analogue without fluorine.

Poly(ε-caprolactone) and Eudragit® microparticles containing fludrocortisone acetate

Substitutive hormonal therapies have to be administered for long periods. Thus, the development of sustained-release forms, as microparticle suspensions, is interesting in order to improve patient compliance by reducing dosing frequencies and side effects. The aim of this work was to compare different formulations of fludrocortisone microparticles for the treatment of mineralocorticoid insufficiency. The study was done with different polymers (poly(epsilon-caprolactone), Eudragit RS and Eudragit RL) and different processes (O/W solvent evaporation methods and S/O/W evaporation methods). The use of a suspension of micronized drug in dichloromethane as dispersed phase (S/O/W method) significantly improved the process. Whereas low concentrations of FLU dissolved in the dispersed phase led to smooth-surface homogeneous microparticles and poor incorporation efficiency (5.8-7.3%); suspensions of FLU led to microparticles with numerous crystals on their surfaces (S/O/W microparticles) and high incorporation efficiency (about 79%). However, the best release profiles were obtained with microparticles prepared with 7.5 mg/ml of dichloromethane, near saturation. Moreover, the use of mixtures of poly(epsilon-caprolactone), Eudragit RS and RL did not improve the release profiles.

Thyrocervical trunk–external carotid artery bypass for positional cerebral ischemia due to common carotid artery occlusion

Medically refractory positional cerebral ischemia and concomitant orthostatic hypotension associated with chronic common carotid artery (CCA) occlusion are rare. The authors detail their experience with three cases treated exclusively by an extracranial bypass in which the thyrocervical trunk was used as the donor vessel. Postoperatively grafts were patent and symptoms resolved in all three patients, although orthostatic hypotension remained. Postural cerebral ischemia due to CCA occlusion can be treated by extracranial bypass surgery. The thyrocervical trunk is a suitable donor for reconstruction of the external carotid artery in these cases.

Longitudinal analysis of growth and puberty in 21-hydroxylase deficiency patients

AIMS

To evaluate growth from diagnosis until final height (FH) in 21-hydroxylase deficiency patients.

METHODS

A retrospective longitudinal study was performed. Only patients treated with hydrocortisone and fludrocortisone (in case of salt wasting) were evaluated. This resulted in a sample of 34 (21 male, 13 female) salt wasting patients (SW) and 26 (13 male, 13 female) non-salt wasting patients (NSW). Auxological data were compared to recent Dutch reference values.

RESULTS

In the first three months of life, the mean length SDS decreased to -1.50, probably because of the high average glucocorticoid dose (40 mg/m2/day). FH corrected for target height (FH(corr)TH) was -1.25 and -1.27 SDS in females and males, respectively. Patients treated with salt supplements during the first year, had a better FH(corr)TH (-0.83 SDS). In NSW patients, FH(corr)TH was -0.96 and -1.51 SDS in females and males, respectively. In SW and NSW, age at onset of puberty was within normal limits, but bone age was advanced. Mean pubertal height gain was reduced in males. Body mass index was only increased in NSW females.

CONCLUSION

In SW, loss of final height potential might be a result of glucocorticoid excess in the first three months and sodium depletion during infancy. In NSW, loss of FH potential was caused by the delay in diagnosis. In SW and NSW, the advanced bone age at onset of puberty (undertreatment in prebertal years) resulted in loss of height gain during puberty. The effect of intensive sodium chloride support in early infancy should be examined prospectively. Neonatal screening is required if the height prognosis in NSW patients is to be improved.

[Fatigue, weight loss and decline in general health in a young patient. Addison disease]

Bei einem 31-jährigen Patienten wird ein Morbus Addison beschrieben. Anschliessend gehen wir auf Ätiologie, Klinik, Diagnostik und Therapie dieses eher seltenen, aber im Alltag dennoch wichtigen Krankheitsbildes ein. Zusätzlich wird die sekundäre Form der Nebennierenrindeninsuffizienz gestreift.

A glucocorticoid-responsive mutant androgen receptor exhibits unique ligand specificity: therapeutic implications for androgen-independent prostate cancer

The cortisol/cortisone-responsive AR (AR(ccr)) has two mutations (L701H and T877A) that were found in the MDA PCa human prostate cancer cell lines established from a castrated patient whose metastatic tumor exhibited androgen-independent growth. Cortisol and cortisone bind to the AR(ccr) with high affinity. In the present study, we characterized the structural determinants for ligand binding to the AR(ccr). Our data revealed that many of the C17, C19, and C21 circulating steroids, at concentrations that are found in vivo, functioned as effective activators of the AR(ccr) but had little or no activity via the wild-type AR or GRalpha. Among the synthetic glucocorticoids tested, dexamethasone activated both GRalpha and AR(ccr), whereas triamcinolone was selective for GRalpha. In MDA PCa 2b cells, growth and prostate-specific antigen production were stimulated by potent AR(ccr) agonists such as cortisol or 9alpha-fluorocortisol but not by triamcinolone (which did not bind to or activate the AR(ccr)). Of the potential antagonists tested, bicalutamide (casodex) and GR antagonist RU38486 showed inhibitory activity. We postulate that corticosteroids provide a growth advantage to prostate cancer cells harboring the promiscuous AR(ccr) in androgen-ablated patients and contribute to their transition to androgen-independence. We predict that triamcinolone, a commonly prescribed glucocorticoid, would be a successful therapeutic agent for men with this form of cancer, perhaps in conjunction with the antagonist casodex. We hypothesize that triamcinolone administration would inhibit the hypothalamic-pituitary-adrenal axis, thus suppressing endogenous corticosteroids, which stimulate tumor growth. Triamcinolone, by itself, would not activate the AR(ccr) or promote tumor growth but would provide glucocorticoid activity essential for survival.

A case of aldosterone-producing adenoma with severe postoperative hyperkalemia

It is known that some patients with primary aldosteronism show postoperative hyperkalemia, which is due to inability of the adrenal gland to secrete sufficient amounts of aldosterone. However, hyperkalemia is generally neither severe nor prolonged, in which replacement therapy with mineralocorticoid is seldom necessary. We report a case of a 46-year-old woman with an aldosterone-producing adenoma associated with severe postoperative hyperkalemia. After unilateral adrenalectomy, the patient showed episodes of severe hyperkalemia for four months, which required not only cation-exchange resin, but also mineralocorticoid replacement. Plasma aldosterone concentration (PAC) was low, although PAC was increased after rapid ACTH test. Histological examination indicated the presence of adrenocortical tumor and paradoxical hyperplasia of zona glomerulosa in the adjacent adrenal. Immunohistochemistry demonstrated that the enzymes involved in aldosterone synthesis, such as cholesterol side chain cleavage (P-450scc), 3beta-hydroxysteroid dehydrogenase (3beta-HSD), and 21-hydroxylase (P-450c21), or the enzyme involved in glucocorticoid synthesis, 11beta-hydroxylase (P-450c11beta), were expressed in the tumor, but they were completely absent in zona glomerulosa of the adjacent adrenal. These findings were consistent with the patterns of primary aldosteronism. Serum potassium level was gradually decreased with concomitant increase in PAC. These results suggest that severe postoperative hyperkalemia of the present case was attributable to severe suppression of aldosterone synthesis in the adjacent and contralateral adrenal, which resulted in slow recovery of aldosterone secretion. It is plausible that aldosterone synthesis of adjacent and contralateral adrenal glands is severely impaired in some cases with primary aldosteronism, as glucocorticoid synthesis in Cushing syndrome.

Initial and postoperative hyponatremia associated with pituitary adenoma: a case report

This 67 year-old man experienced 3 episodes of symptomatic hyponatraemia. Radiological examination revealed a sellar lesion and the tumour was removed via the transsphenoidal route. Thereafter, he simultaneously developed intractable diabetes insipidus and serious hyponatraemia with persistent natriuresis. His level of atrial natriuretic peptide was not significantly elevated, however, his plasma aldosterone concentration was low. The oral administration of salt gradually improved his hyponatraemia as well as the coincident symptoms. By the administration of a mineralocorticoid, fludrocortisone acetate, we succeeded in maintaining his serum sodium level without salt replacement. We discuss the mechanism(s) and treatment of hyponatraemia associated with pituitary tumour.

Rat 11 beta-hydroxysteroid dehydrogenase type 2 enzyme is expressed at low levels in the placenta and is modulated by adrenal steroids in the kidney

The 11 beta-hydroxysteroid dehydrogenase type II enzyme (11 beta HSD2) protects the non-discriminating mineralocorticoid receptor from occupation by glucocorticoids. In man the enzyme is also highly expressed in the placenta where it is thought to also protect the fetus from the high circulating levels of maternal glucocorticoids. Mutations in the HSD11B2 gene have recently been shown to account for the syndrome of apparent mineralocorticoid excess. In the present study we have used a rat 11 beta HSD2 cDNA to study the distribution and regulation of this enzyme. The rat protein is highly homologous to the mouse, rabbit and human enzymes, except for the carboxy-terminal region which displays extensive divergence between species beyond residue 382. Northern blot analysis of rat total RNA showed that the single copy gene is highly expressed in kidney and adrenal with lower levels in the colon; surprisingly, there was no detectable signal in the placenta. There was also no detectable mRNA in the liver, heart, hippocampus, testis, thymus and pancreas. Nuclease protection analysis revealed the presence of moderate 11 beta HSD2 message levels in the parotid and exceedingly low levels in the placenta. Regulation studies showed that administration of dexamethasone, deoxycorticosterone and 9 alpha-fluorocortisol to adrenalectomized rats for 7 days increased renal enzyme activity 33%-50%, while message levels decreased 35%-70%, suggesting that the increased enzyme activity may represent activation of latent enzyme.

Potassium supplementation ameliorates mineralocorticoid-induced sodium retention

Potassium depletion induced by dietary potassium restriction causes sodium retention while potassium supplementation augments urinary sodium excretion. The role of external potassium balance in modulating mineralocorticoid-induced sodium retention in humans is unknown. Accordingly, eight healthy subjects were studied at the Clinical Research Center receiving a constant diet providing (per kg body wt) sodium 2.5 mmol, potassium 1.1 mmol daily. After establishing basal sodium and potassium balance over three days, each subject received 9 alpha-fludrocortisone 0.4 mg/day for 10 days. Subjects were studied twice, four to eight weeks apart, in a double blind, randomized crossover design receiving either placebo or additional KCl (80 mmol/day) over the 10 day study period. Serum potassium concentrations were unchanged from basal values on KCl while the values fell (4.1 +/- 0.1 vs. 3.4 +/- 0.1 mmol/liter, P = 0.01) on placebo. Urinary sodium excretion decreased with fludrocortisone administration in both groups, but this decrease reached significance only in the placebo group. Furthermore, during fludrocortisone administration the sodium excretion rates on KCl were significantly higher compared to the values noted on placebo (134 +/- 8 vs. 112 +/- 13 mmol/day, P = 0.01). Body weight recorded after 10 days of fludrocortisone administration was higher on placebo compared to KCl (72.3 +/- 2.8 vs. 71.6 +/- 2.8 kg, P = 0.01). Plasma renin activity, and aldosterone concentrations decreased on fludrocortisone while atrial natriuretic peptide levels increased. These studies suggest that amelioration of hypokalemia attenuates mineralocorticoid-induced sodium retention. Therefore, potassium depletion may contribute to the mineralocorticoid-induced sodium retention.

Evidence that high dose cortisol-induced Na+ retention in man is not mediated by the mineralocorticoid receptor

We have previously shown that high dose cortisol (F; 240 mg/day)-induced Na+ retention and systolic blood pressure (BP) increases are not inhibited by the glucocorticoid (type II) receptor antagonist RU486. Adequacy of type II receptor blockade with RU486 was clearly demonstrated, indicating that the Na+ retention was not mediated through the glucocorticoid receptor. Spironolactone (Sp: 400 mg/day), in a preliminary assessment, also did not inhibit F-induced Na+ retention. The purpose of this study was to determine whether the Na+ retention produced by F administration is mediated by the type I receptor by comparing the effects of F to a potent type I agonist [9 alpha-fludrohydrocortisone (9 alpha FF)] with and without Sp administration. The effects of the two agonists and Sp on urinary K excretion and BP were also compared. Normal male volunteers, on a constant daily diet for 10 days, received either F (240 mg/day) or 9 alpha FF (3.0 mg/day) with or without Sp (400 mg/day) for the last 5 days. The mean cumulative reductions in Na+ excretion during the 5 days compared to baseline values before hormone administration were 255 +/- 38 and 494 +/- 81 mmol/5 days for F (n = 9) and 9 alpha FF (n = 5), respectively (P = 0.01). Sp (n = 5) completely inhibited 9 alpha FF-induced Na+ retention (494 +/- 81 vs. -37 +/- 130 mmol/5 days; P less than 0.01), but had no effect (n = 5) on F-induced Na+ retention (255 +/- 38 vs. 193 +/- 50 mmol/5 days; P = NS). After the expected first day kaliuresis, the effects of both steroids on net cumulative urinary K+ excretion were minimal. Systolic BP was increased by F, but not 9 alpha FF, and Sp did not inhibit this increase. A 2-fold greater Sp-inhibitable Na(+)-retaining effect of the mineralocorticoid demonstrates that the failure of Sp to block F-induced Na+ retention is not due to inadequate type I receptor blockade. Based on these findings and earlier studies, we conclude that high dose (stress level) F-induced Na+ retention and systolic BP increase are not mediated by either the mineralo- or glucocorticoid receptor in normal man.

Histological and biochemical distinctiveness of atypical aldosterone-producing adenomas responsive to upright posture and angiotensin

Fifteen patients with primary aldosteronism were classified as angiotensin II-unresponsive aldosterone-producing adenoma (AII-U APA, n = 9), or angiotensin II-responsive aldosterone-producing adenoma (AII-R APA, n = 6), based on the responsiveness of aldosterone to upright posture and to angiotensin II infusion. Lack of aldosterone response to angiotensin II infusion immediately postoperatively in the AII-R APA subtype was consistent with previous responsiveness residing solely within the adenoma. Cortisol levels in five of the six patients with AII-R APA failed to suppress normally with dexamethasone consistent with some autonomous production of cortisol by the adenoma. In contrast, cortisol levels suppressed normally during dexamethasone administration in all patients with AII-U APA. This biochemical distinction can be added to the previously described overproduction of 18-oxo cortisol in AII-U APA but not in AII-R APA. Histological examination of adenoma sections revealed predominantly (greater than or equal to 50%) zona fasciculata type cells in AII-U APA. In contrast, AII-R APA contained less than 20% zona fasciculata type. Thus, biochemical differences between AII-U APA and AII-R APA subtypes of primary aldosteronism may be due to underlying differences in cellular composition of the aldosterone-producing adenomas.

Effect of fludrocortisone acetate in patients with subarachnoid hemorrhage

In this study with randomized controls, we administered fludrocortisone acetate to 46 of 91 patients with subarachnoid hemorrhage in an attempt to prevent excessive natriuresis and plasma volume depletion. Fludrocortisone significantly reduced the frequency of a negative sodium balance during the first 6 days (from 63% to 38%, p = 0.041). A negative sodium balance was significantly correlated with decreased plasma volume during both the first 6 days (p = 0.014) and during the entire 12-day study period (p = 0.004). Although fludrocortisone treatment tended to diminish the decrease in plasma volume, the difference was not significant (p = 0.188). More patients in the control group developed cerebral ischemia (31% vs. 22%) and, consequently, more control patients were treated with plasma volume expanders (24% vs. 15%), which may have masked the effects of fludrocortisone on plasma volume. Fludrocortisone therefore reduces natriuresis and remains of possible therapeutic benefit in the prevention of delayed cerebral ischemia after aneurysmal subarachnoid hemorrhage.

Glucocorticoid and mineralocorticoid stimulation of atrial natriuretic peptide release in man

To investigate the influence of a mineralocorticoid and a glucocorticoid on plasma immunoreactive atrial natriuretic peptide (irANP) and possible functional correlates, eight normal men received in random order 9 alpha-fludrocortisone acetate (9 alpha F; 0.6 mg/day), prednisone (50 mg/day), and placebo each for 9 days. Their diet contained 130 mmol sodium and 75 mmol potassium daily. The mean supine plasma irANP levels were similar on days 2, 4, and 9 of placebo treatment [25 +/- 10 (+/- SE), 27 +/- 5, and 27 +/- 6 pmol/L, respectively]. Mean plasma irANP levels were 76 +/- 42 (P less than 0.05), 89 +/- 34, and 93 +/- 29 pmol/L (P less than 0.01), respectively, on days 2, 4, and 9 during 9 alpha F administration, and 68 +/- 37 (P less than 0.05), 83 +/- 41, and 48 +/- 18 pmol/L on the same days during prednisone administration. Compared with the placebo period, sodium intake minus urinary output during 9 alpha F administration averaged +41 mmol at the time of blood sampling on day 2, +112 mmol on day 4, and +149 mmol on day 9; body weight was unchanged on day 2 and increased by 0.7 and 1.1 kg on days 4 and 9, respectively. Escape from 9 alpha F-induced renal sodium retention occurred on days 5 and 6. During prednisone administration, sodium intake minus urinary output and body weight did not change. Plasma volume and BP rose significantly during 9 alpha F (P less than 0.05) but not during prednisone administration. Plasma renin, aldosterone, and norepinephrine (NE) decreased during 9 alpha F treatment (P less than 0.05 to less than 0.01); during prednisone treatment, plasma aldosterone levels were lower on day 9 only. Cardiovascular pressor responsiveness to angiotensin II was enhanced during 9 alpha F but not prednisone administration, while blood pressure reactivity to NE was not significantly modified. These findings demonstrate that 9 alpha F and prednisone in high doses provoke remarkably similar increases in plasma irANP, but that the glucocorticoid-induced rise in plasma irANP is due to a mechanism other than sodium and volume retention.

An alternative protocol for the medical management of canine pituitary-dependent hyperadrenocorticism

As an alternative to the o,p'-DDD treatment aimed at the selective destruction of the adrenal cortices, the authors have introduced a protocol aimed at the complete destruction of the adrenal cortices. It consists of a longer period of daily treatment with o,p'-DDD and lifelong substitution for primary hypoadrenocorticism. The results obtained in 41 dogs, with a minimum follow-up period of one year, indicate that this approach has advantages over lifelong maintenance therapy with o,p'-DDD.