The metabolism of 9 alpha-fluorinated steroids in the human kidney

We compared the renal metabolism of 9 alpha-fluorinated steroids with that of the unfluorinated, endogenous steroid cortisol (F). By defining kinetic variables, we characterized isoenzyme activities of 11 beta-hydroxysteroid-dehydrogenase (11 beta-HSD).

METHODS

I) In human kidney slices, we studied the conversion of 9 alpha-fluoro-cortisol (FF) and F to their oxo-products (and vice versa). II) In human kidney microsomes, we performed the kinetic analysis of 11 beta-HSD activity for the steroid pairs F/cortisone (E) and dexamethasone (D)/11-dehydro-dexamethasone (DH-D).

RESULTS

I) In kidney slices, FF is very weakly oxidized to 9 alpha-fluorocortisone (FE), while the reduction of FE to FF is very effective. In contrast, E is hardly reduced to F, but F is strongly inactivated to E. II) Enzyme kinetics in kidney microsomes: 1a) Oxidation of F to E: exclusively NAD-dependent; K(m) = 25.5 nmol/L. b) Reduction of E to F: clearly NADH-preferring; K(m) = 81 nmol/L; Vmax(oxidation) /Vmax(reduction) (F/E) = 26.2a) Oxidation of Dtto DH-D: exclusively NAD-dependent; K(m) = 81 nmol/L b) Reduction of DH-D to D: exclusively NADH-dependent; K(m) = 68 nmol/L; Vmax(oxidation)/Vmax(reduction) (D/DH-D) = 0.09. Thus, the equilibrium of FF/FE in human kidney slices is far on the biologically active hydroxy-side. This shift, induced by the 9-fluorination, gives a good explanation for its mineralocorticoid potency. The cosubstrate dependence and the K(m)-value of the oxidation of F are similar to those of the cloned human 11 beta-HSD-II. For the first time, we could show a NADH-dependent reduction of E to F. Moreover, we found that the preference of D/DH-D for the reductase reaction (see the quotients Vmax(oxidation)/Vmax(reduction)) is due toaa NADH-dependent enzyme (probably 11 beta-HSD-II). These results provide strong evidence against the "dogma" of an "unidirectional" 11 beta-HSD-II.

Parasellar chronic inflammatory disease presenting Tolosa-Hunt syndrome, hypopituitarism and diabetes insipidus: a case report

We describe a 60-year-old man with a history of Tolosa-Hunt syndrome associated with intermittent painful ophthalmoplegia and a visual disturbance on the left side, who presented with signs and symptoms of severe hypoadrenalism and diabetes insipidus. Magnetic resonance imaging demonstrated enlargement of the hypophysis and infundibulum and left cavernous sinus. An endocrinologic study revealed anterior pituitary dysfunction and diabetes insipidus. The patient underwent a transsphenoidal biopsy which revealed chronic inflammation in the hypophysis, mucosa of the sphenoid sinus, and dura mater. The patient was treated with steroids that decreased the size of the hypophysis and infundibulum, but the symptoms of anterior pituitary insufficiency and diabetes insipidus have persisted. The chronic inflammation of the hypophysis and infundibulum is thought to have spread from the cavernous sinus.

Therapy of systemic histoplasmosis in immunosuppressed mice with the triazole D0870

Because histoplasmosis is a life-threatening disease in AIDS and other compromised patients, we examined the efficacy of D0870 (Zeneca) in immunosuppressed mice against systemic histoplasmosis. Oral therapy with fluconazole given once daily (QD) was ineffective in prolonging survival, whereas itraconazole given once or twice daily (BID), fluconazole given BID or D0870 given QD or given every other day (QOD) were efficacious (P < 0.001). Burdens of Histoplasma capsulatum in the liver and spleen of survivors showed that D0870 given QD or QOD and itraconazole given BID caused dose-responsive reduction of infectious burden. Infection was cleared more readily from the liver than from the spleen. Overall, D0870 was > or = 20-fold more efficacious than fluconazole or itraconazole and itraconazole was > ten-fold better than fluconazole for the treatment of systemic histoplasmosis in the immunosuppressed model.

Murine model of invasive pulmonary aspergillosis following an earlier stage, noninvasive Aspergillus infection

Aspergillus spp. occasionally cause invasive pulmonary aspergillosis following noninvasive infection in patients with underlying bronchopulmonary disorders regardless of their systemic immunological conditions. We developed a murine model of invasive pulmonary aspergillosis following an earlier stage, noninvasive Aspergillus infection. BALB/c mice were inoculated intratracheally with agarose beads containing Aspergillus fumigatus conidia. Two weeks after inoculation, half of the mice were immunosuppressed with cortisone acetate. During a 4-week observation period, the survival rate of infected immunosuppressed mice was significantly lower (P < 0.01) than that of infected nonimmunosuppressed mice. The number of CFU in the lungs gradually decreased in the nonimmunosuppressed mice, whereas a time-related significant increase (P < 0.05) of CFU was demonstrated in the immunosuppressed mice. In the lungs of the nonimmunosuppressed mice, there was marked accumulation of neutrophils, lymphocytes, and macrophages (in this order) around the agarose beads in the bronchi. Aspergillus hyphae were surrounded by the inflammatory cells and did not invade the lung parenchyma. In contrast, in the immunosuppressed mice, Aspergillus hyphae proliferated markedly and invaded the lung parenchyma after immunosuppression. In this model, the two-dimensional extents of the lesions were also evaluated with an image-processing system. Time-related increase of the area of peribronchial necrotic lesions was significant (P < 0.05) after immunosuppression. This model should therefore be useful for investigating the pathophysiology of noninvasive Aspergillus infection and invasive pulmonary aspergillosis and also for clarifying the mechanism of conversion to the invasive disease from the noninvasive stage.

Atrial natriuretic peptide and plasma renin levels in assessment of mineralocorticoid replacement in Addison's disease

Assessment of mineralocorticoid replacement therapy in Addison's disease relies on clinical features and laboratory measurements, including plasma renin and potassium. Previous studies have questioned the value of measuring the plasma renin concentration (PRC), particularly in the setting of fludrocortisone overreplacement. The aim of this study was to evaluate the usefulness of plasma atrial natriuretic peptide (ANP) measurements as a marker of sodium and volume status in Addison's disease. Fourteen patients with Addison's disease receiving their usual glucocorticoid doses were placed on various doses of fludrocortisone (FC; 0 mg, 0.05 mg, 0.1 mg and 0.2 mg) in random order for four 2-week periods. At the end of each period, blood pressure and clinical symptoms were assessed, and blood was drawn for measurement of PRC and ANP levels. PRC was significantly elevated in patients receiving placebo (54.2 +/- 57.9 ng/mL x h) compared with PRC in those receiving baseline FC (24.7 +/- 42.4 ng/mL x h), 0.1 mg FC (15.2 +/- 25.9 ng/mL x h), and 0.2 mg FC (5.5 +/- 5.7 ng/mL x h). ANP levels were measured by either an extraction method (ANP(ext)) or directly from plasma (ANP(dir)). ANP(dir) was significantly elevated at 0.2 mg FC (87.1 +/- 20.1 pg/mL) compared with baseline (63.3 +/- 8.1 pg/mL), placebo (56.1 +/- 5.5 pg/mL), 0.05 mg FC (60.5 +/- 16.0 pg/mL), and 0.1 mg FC (65.4 +/- 13.7 pg/mL) values. ANP(ext) was elevated in patients receiving 0.2 mg FC (42.7 +/- 41.8 pg/mL) compared with that in patients receiving placebo (7.9 +/- 5.4 pg/mL), 0.05 mg FC (16.2 +/- 11.2 pg/mL), or 0.1 mg FC (19.7 +/- 11.1 pg/mL). Our data suggest that PRC is of value in determining mineralocorticoid underreplacement, whereas ANP is a more sensitive index of FC overreplacement. ANP levels may, therefore, be complementary to PRC in adjustment of mineralocorticoid doses in the upper dose range, where clinical symptoms and signs appear to be of little value.

Serum IgG antibody response to Pneumocystis carinii among immunosuppressed, malnourished and healthy rats

Pneumocystis carinii is an important opportunistic pulmonary pathogen that causing pneumonia in premature infants, children with immunodeficiency diseases and patients of all ages receiving immunosuppressive agents. In this work, humoral immune responses to this organism were studied, using IFAT during the period of infection and recovery of immunosuppressed and malnourished rats compared to healthy group. Where sever pneumonitis similar to that seen in humans can be induced in this experimental model. Serum IgG antibody titers to the organism were absent in rats administered corticosteroids but rose after steroid tapering with disappearance of the organism from their lungs due to reactivation of the immune system. While in malnourished infected rats, clearance of the organism had occurred after regaining the protein diet with progressive increase in IgG level denoting their immunocompetent state. IgG antibody appeared in the serum of control healthy rats with the progress of age at low non diagnostic level indicating the presence of dormant parasites in their lungs.

Bilateral isolated adrenal coccidioidomycosis

A case of bilateral isolated adrenal coccidioidomycosis in a previously healthy and immunocompetent 43-year-old Caucasian male is presented. He had never travelled to a coccidioidomycosis endemic area. Subclinical adrenal dysfunction was found with elevated plasma ACTH and mineralocorticosteroid and androgen pathway abnormalities. The implement of the fungal infection on adrenal function, and the diagnosis and management of adrenal coccidioidomycosis are discussed.

Anticryptococcal activity by alveolar macrophages from rats treated with cortisone acetate during different periods of time

The effect of cortisone acetate (CA) treatment on the anticryptococcal activity by rat alveolar macrophages (AM) was investigated. The animals received a weekly dose of 5 mg CA during 1, 2, 3 or 4 weeks. Following the final dose the AM were collected by lung lavage and challenged with Cryptococcus neoformans. Parallel experiments with silica particles of a similar size were performed. The phagocytic function was assessed using a fluorescence method that distinguishes between attached and ingested particles. The oxidative metabolism was studied by the nitroblue tetrazolium (NBT) reduction test. The accumulated attachment (a measure of the attachment process) of cryptococci and silica particles per AM was significantly depressed after the third and fourth week of CA treatment. The ingested fraction (a measure of the ingestion process) of cryptococci but not of silica particles showed a small but significant decrease after the fourth week. The NBT reduction of the unstimulated AM and those stimulated with either the cryptococci or silica particles for 24 h was significantly reduced after the fourth week of treatment. In conclusion, these results demonstrate that high dose CA treatment primarily affects the attachment of the cryptococci to the AM and to a lesser extent also the ingestion process. In addition, it decreases the NBT reduction by AM in response to the yeast. The impairment of the AM anticryptococcal activity by high doses of CA constitutes a risk of dissemination of C. neoformans from the lungs.

Corticosteroid alteration of carboplatin-induced hematopoietic toxicity in a murine model

Corticosteroids exhibit extensive hematopoietic effects both in vitro and in vivo. Some of the previously studied effects suggested that corticosteroids may alter hematopoietic toxicity of chemotherapeutic agents. In this study, we examined (1) the optimum dose and schedule of cortisone acetate (CA) to reduce hematopoietic toxicity of carboplatin (CB) and (2) possible mechanisms involved in this protective effect. CA given subcutaneously at 0.5 mg/d per mouse for 7 days before CB reduced CB-induced mortality due to neutropenia from 88% in controls to 14% in CA-treated mice (P < .05). Lower CA doses were not effective. Three days of pretreatment (but not 1 day) was as effective as 7 days. CA given after CB had no effect on mortality. Pharmacokinetic studies of CA at 0.5 mg per mouse demonstrated blood levels of cortisol achievable in patients (peak level, 82 micrograms/dL). CA treatment markedly reduced spleen cell number and colony-forming units-granulocyte/macrophage (CFU-GM) as well as bone marrow CFU-GM. Bone marrow CFU-GM removed from CA-treated mice demonstrated increased resistance to platinum and increased resistance to high specific activity 3H-thymidine. These findings suggest that treatment of mice with CA induces cellular resistance of hematopoietic precursors to platinum and, thus, reduces CB hematotoxicity. CA or other corticosteroids may be useful in reducing clinical toxicity of CB.

[Congenital adrenal hypoplasia and hearing loss. A case report]

We report on the diagnostics, the therapeutics and the follow-up (to 3 years and 5 months) of a newborn affected by X-linked congenital adrenal hypoplasia. After the beginning of substitute hormonal therapy, the patient underwent periodical clinical examinations, with particular attention to the growth, and laboratory tests, which monitored the hormonal pattern. This experience points out the diagnostic role of low maternal levels of urinary estriol during pregnancy and the importance of a prolonged follow-up, so as to discover associated pathologies as early as possible. In our case, in fact, the study of auditory brainstem responses enabled us to recognize a mild transmission hearing loss at the early age of 8 months.

Growth patterns and outcomes in congenital adrenal hyperplasia; effect of chronic treatment regimens

AIM

To assess outcome (final height and sexual maturation), growth patterns and blood pressure in 16 children with congenital adrenal hyperplasia treated at one institution over a 30 year period.

METHODS

Growth patterns and maturation were determined by retrospective review (median follow up period 14 years). Dose adjustment of corticosteroid replacement treatment, sufficient to maintain normal levels of adrenal precursor secretion, was determined using assays of urinary pregnanetriol excretion (up to 1975) or early morning measurements of plasma 17 hydroxy progesterone and plasma renin activity at intervals of 4-6 months.

RESULTS

In 7 of 15 patients the growth pattern during infancy was retarded--13 not exceeding the population mean. Catchup growth as steroid dose fell with age was not usually observed. In boys, height potential was further compromised by a significant reduction in growth velocity during puberty. None of nine patients evaluated at final height had attained the target height. During the first year of life, plasma renin activity was suppressed below the reference range in six of nine infants. Despite this, and lower than normal levels of plasma renin activity in childhood, most children were normotensive.

CONCLUSIONS

Avoiding salt depletion in infancy and excessive androgen secretion during childhood do not ensure normal growth patterns or normal final height. Impaired final height in congenital adrenal hyperplasia is more likely to be due to over treatment, particularly in infancy when lower doses of corticosteroids may improve height prognosis.

Adult height in women with early-treated congenital adrenal hyperplasia (21-hydroxylase type): relation to body mass index in earlier childhood

To investigate if obesity, as judged by increased body mass index (BMI), during childhood is associated with impaired adult stature in patients with 21-hydroxylase-type congenital adrenal hyperplasia (CAH), a retrospective analysis was carried out on outpatient records of 30 girls with CAH who had reached adult height. Height SD score for age (HtSDS(ca)), HtSDS for bone age (HtSDS(ba)), BMI and steroid dosage in early childhood (3.2-4.6 years) and later childhood (7.2-9.1 years), were compared with adult HtSDS (HtSDS(adlt)), adult HtSDS less mid-parental HtSDS (HtSDS(adlt)-HtSDS(mp)), predicted adult height SDS (HtSDS(pdct)), adult height SDS less predicted adult HtSDS (HtSDS(adlt)-HtSDS(pdct)) and age at menarche. Mean (SD) for HtSDS(adlt) was -1.13 (1.05), mean HtSDS(pdct) -0.12 (0.9) and mean age at menarche 13.5 (1.9) years. BMI in childhood was not correlated with HtSDS(adlt) but showed negative correlations with HtSDS(adlt)-HtSDS(mp) (r = -0.43; p < 0.02) and HtSDS(adlt)-HtSDS(pdct) (r-0.45; p < 0.02). BMI in later childhood showed negative correlations with HtSDS(adlt)-HtSDS(pdct) (r = -0.61; p < 0.001) and age at menarche (r = -0.63; p < 0.001). We conclude that in girls with early-treated CAH, a high BMI during early childhood is associated with loss of genetic height potential, and in later childhood with over-prediction of adult height and early menarche.

Hormone-refractory (D3) prostate cancer: refining the concept

OBJECTIVES

A wide range of responses have been reported to second-line hormonal therapies, including corticosteroids and the withdrawal of antiandrogens in patients with hormone-refractory prostate cancers. This suggested the need to classify patients on the basis of hormonal sensitivity. A schema was developed by assessing the differences in entry criteria in relation to outcomes for clinical protocols with hydrocortisone alone or in combination with other agents for patients who had progressed after primary hormone therapy.

METHODS

Published clinical trials of patients who had progressed after primary hormone treatment, which included glucocorticoids, were retrieved from Medline listings. The trials included patients treated with hydrocortisone alone, hydrocortisone and aminoglutethimide, hydrocortisone plus suramin, dexamethasone, and prednisone alone or in combination with chemotherapy.

RESULTS

The definitions used for refractory disease ranged from none, to "progression", to "unsuccessful second medical or surgical castration. "None of the trials included a definition for hormone-refractory disease based on objective criteria. Details were lacking on most trials with respect to the response to and specific types of hormonal therapies. Furthermore, few trials controlled for the potential contribution of the "flutamide withdrawal syndrome" on outcome.

CONCLUSIONS

The term "hormone-refractory" prostate cancer has evolved to include patients with a spectrum of diseases. As utilized in clinical trials of second-line hormonal therapies, patients who have received one and as many as six different treatments have been included in the same study. A new classification of patients based on hormonal sensitivity is proposed to recognize that androgen-independent proliferation, progression of disease despite castrate levels of testosterone, does not necessarily mean that a tumor is refractory to hormonal manipulations. Future trials in hormonally relapsed patients must include more details of the hormonal therapies utilized.

Effect of povidone iodine dermatologic ointment on wound healing

OBJECTIVE

To evaluate the effect of topical povidone iodine ointment on wound healing.

MATERIALS AND METHODS

60 female mice randomly divided into four groups, A-D. Each mouse had a 2 cm linear incision made on the dorsal skin. Group A had povidone iodine ointment, and group B had ointment base applied for 7 days to the healing incision. Group C were given steroids for 7 days, and group D were allowed to heal without treatment. On Day 8, the strength of the incision was tested with an in vivo tensometer, and the hydroxyproline content of the incision was determined.

RESULTS

Using ANOVA and Fischer's LSD test (P < 0.05), povidone iodine as well as steroid groups had significantly reduced wound strengths as compared to the controls and the group with ointment base. No significant difference in the hydroxyproline content was seen.

CONCLUSIONS

Povidone iodine significantly reduces wound strength without reducing the total hydroxyproline content of the wound.

Sex- and tissue- specific regulation of 11 beta-hydroxysteroid dehydrogenase mRNA

In the present study we have investigated the effect of hypophysectomy on 11 beta HSD1 gene expression in a variety of tissues from male and female rats. Of the tissues analysed significant changes were observed only in the male and female livers, and in the female kidney. Hypophysectomy (hypox) increased hepatic message levels in the female 20-fold, and male levels rose 2-fold. Male renal 11 beta HSD1 message levels remained constant following hypophysectomy, whereas female renal 11 beta HSD1 mRNA levels increased approximately 2-fold. In intact animals hepatic 11 beta HSD1 mRNA levels are 18-fold lower in the female than the male, while renal levels are 1.4-fold higher in the male than the female. Hepatic 11 beta HSD1 levels in the female rat appear critically responsive to the pattern of growth hormone (GH) administration. Twice daily injections of GH had no significant effect on hepatic message levels in the hypox female rat, whereas constant infusions of GH, via an osmotic mini-pump produced a marked decrease. Renal 11 beta HSD1 mRNA levels were demonstrated to be under the regulation of estrogen, and 11 beta HSD1 enzyme activity in both liver and kidney correlated with the observed changes in mRNA levels. 11 beta HSD1 gene expression is thus regulated in a tissue-specific and sexually dimorphic manner.

Adherence of germ tubes of Candida albicans to tissues from immunocompromised mice

The influence of immune status of the host on binding of germ tubes of Candida albicans to murine tissue sections in an ex vivo assay was examined. Generally, germ tubes appeared randomly adhered to the tissues examined and binding was unaffected by immunodeficiency induced by treatment with cyclophosphamide and cortisone acetate. Adherence was somewhat reduced in spleen and kidney sections or increased in liver sections and unchanged in lymph node sections from treated mice compared to sections from control animals. Scanning electron micrographs showed organisms appeared to be loosely or tightly bound to the surface or partially embedded in spleen sections from both control and treated mice. These observations suggested that qualitative and quantitative difference in adhesion of germ tubes to various tissues may contribute little to the susceptibility of the immunodeficient animal to candidal infection.

Reproducibility of the dose-response curve of steroid-induced cleft palate in mice

Pregnant CD-1 mice were exposed to cortisone acetate at doses ranging from 20 to 100 mg/kg/day on days 10-13 by oral and intramuscular routes. Multiple replicate assays were conducted under identical conditions to assess the reproducibility of the dose-response curve for cleft palate. The data were fitted to the probit, logistic, multistage or Armitage-Doll, and Weibull dose-response model separately for each route of exposure. The curves were then tested for parallel slopes (probit and logistic models) or coincidence of model parameters (multistage and Weibull models). The 19 replicate experiments had a wide range of slope estimates, wider for the oral than for the intramuscular experiments. For all models and both routes of exposure the null hypothesis of equality of slopes was rejected at a significant level of p < 0.001. For the intramuscular group of replicates, rejection of slope equality could in part be explained by not maintaining a standard dosing regime. The rejection of equivalence of dose-response curves from replicate studies showed that it is difficult to reproduce dose-response data of a single study within the limits defined by the dose-response model. This has important consequences for quantitative risk assessment, public health measures, or development of mechanistic theories which are typically based on a single animal bioassay.

An experimental trial of artemether in treatment of Pneumocystis carinii in immunosuppressed rats

An immunosuppressed rat model was established by injecting cortisone acetate 25 mg/rat twice a week for 4 weeks and 12.5 mg/rat for another 2 weeks subcutaneously. A development of Pneumocystis carinii pneumonia (PCP) was found at the end of the 6th week in all rats. These rats were injected intramuscularly with artemether at 100 mg/kg once a day for 5 consecutive days. All rats were necropsied at the end of the 8th week. The lung impression smears were stained with Gomori's stain, and Pneumocystis carinii cysts were counted. The ultrastructural changes of trophozoite, precyst and cyst were investigated by transmission electron microscopy on the 7th day after treatment.

Corticosteroid modulation of interleukin-1 hematopoietic effects and toxicity in a murine system

Interleukin-1 (IL-1) has been shown to ameliorate the hematopoietic toxicities of antitumor chemotherapeutic agents in both mice and humans. However, IL-1 toxicity in humans is considerable and is similar to the systemic inflammatory toxicities induced by IL-3, IL-6, and other cytokines with pleiotropic biologic activities, eg, fever, nausea, malaise, and hypotension. We hypothesized that corticosteroids may reduce IL-1 toxicity without reducing IL-1 hematopoietic effects in vivo. C3H/HeJ mice (female, 6 weeks) were treated for 7 days subcutaneously with cortisone acetate (CA), (0.1, 0.25, or 0.5 mg/d/mouse), intraperitoneally with IL-1 (1 or 2 micrograms/d/mouse), or both. As expected, IL-1 increased white blood cell counts, splenic granulocyte-macrophage colony-forming units, and spleen cell number, and protected mice from lethal doses of carboplatin (200 mg/kg; Paraplatin, Bristol Laboratories, Evansville, IN) administered the day after completion of the 7 days of IL-1 administration. CA did not significantly block the hematopoietic effects of IL-1 or the ability of IL-1 to protect mice from the hematopoietic toxicity of carboplatin. IL-1 administered to mice at 8 micrograms/d/mouse for 5 days induced decreased activity, roughening of hair, diarrhea, pancytopenia, multiple metabolic abnormalities, and death in 60% of mice. IL-1 at the therapeutic doses (0.5 to 2 micrograms/d) was not toxic. CA in a dose-dependent manner blocked all of the above mentioned toxicities when administered 24 hours and 30 minutes before each IL-1 injection. CA also decreased IL-1-induced increase in plasma tumor necrosis factor levels at the time point examined.

Oedema in patients with Addison's disease on replacement therapy: glucocorticoid excess and mineralocorticoid deficiency?

Steroid hormones influence mechanisms related to oedema formation, including postural vasoconstriction and vascular tone. We studied fifteen patients (7 male, 8 female) with primary adrenal failure on clinically optimal replacement therapy. Five patients, all female, had clinically detectable oedema. Patients with oedema had evidence of mineralocorticoid deficiency, with increased supine and erect plasma renin activity and greater postural fall in blood pressure. Mean morning plasma cortisol levels were significantly higher in the group with oedema, suggesting they were receiving insufficient mineralocorticoid and a possible relative excess of glucocorticoid. There were no significant differences between patients with and without oedema in lower-limb cutaneous blood flow or in postural vasoconstrictor responses measured by laser Doppler flowmetry. The mechanism of oedema formation is unclear, but appears not to be modulated by haemodynamic mechanisms with expansion of intravascular volume or, in contrast to the known effects of sex hormones, by impairment of postural vasoconstriction. Theoretically, excess glucocorticoid replacement may result in oedema formation, by direct action on vascular tone, by altering capillary permeability, or by influencing other factors such as atrial natriuretic peptide. Measurement of plasma renin activity in conjunction with plasma cortisol profiles may be useful in adjusting replacement therapy in patients with Addison's disease and oedema.

[Histopathological study of experimental recurrent pulmonary aspergillosis--the comparative study of steroid and cyclophosphamide induced models]

A new animal model of recurrent pulmonary aspergillosis was established using cyclophosphamide (CPM) instead of cortisone acetate for reconstitution of immunosuppression, and histopathological findings were compared with those of the previous model. A recurrence of pulmonary aspergillosis, according to granulocytopenic conditions was much more rapid and uniform in this model than that of steroid induced model shown. In histopathologically, invasive and massive proliferation of Aspergillus hyphae was observed in lungs of rats 5-7 days after the CPM treatment and hyphal invasion into pulmonary vessels which suggested rapid systemic spreading of the infection was also found. This model considered to be good for the simulation of recurrent aspergillosis in patients with severe immunosuppression and also useful for studies of new diagnostic and therapeutic methods of recurrent pulmonary aspergillosis.

Impaired renal 11 beta-oxidation of 9 alpha-fluorocortisol: an explanation for its mineralocorticoid potency

9 alpha-Fluorocortisol (9 alpha FF) is about 200 times more potent as a mineralocorticoid than cortisol (F) in man, although it binds with the same affinity as F and aldosterone to the human mineralocorticoid receptor. The low mineralocorticoid activity of F has been shown to be due to its rapid conversion by the kidney to cortisone (E), which does not bind to the receptor. Therefore, we compared the conversion of F to E with that of 9 alpha FF to 9 alpha-fluorocortisone (9 alpha FE) by 11-hydroxysteroid dehydrogenases in man in vivo and in vitro. Single oral doses of 9 alpha FF, 9 alpha FE, and F were given to normal males, and the excretion of free 9 alpha FF, 9 alpha FE, F, and E was measured in urine. Human kidney and liver slices were incubated with unlabeled steroids, and the free 11-hydroxy- and 11-oxosteroids were quantitated after high performance liquid chromatography separation by UV absorption. Oral F (5 mg) is excreted 70% as free E and 30% as free F (percentage of free steroids only). Oral 9 alpha FF (5 mg) is excreted 90% as free 9 alpha FF and 10% as free 9 alpha FE. Free 9 alpha FF excretion is 14 times greater than that of F after ingesting an identical dose. Oral 9 alpha FE (4 mg) is also excreted 90% as 9 alpha FF and 10% as 9 alpha FE. Kidney slices convert F much faster to E than 9 alpha FF to 9 alpha FE. The conversion of 9 alpha FE to 9 alpha FF is, on the contrary, much faster than that of E to F. Thus, the equilibrium of the reaction is on the 11-oxo side for F/E and on the 11-hydroxy side for 9 alpha FF/9 alpha FE. The interconversion of both pairs of steroids is inhibited by glycyrrhetinic acid in a dose-dependent manner. Liver slices do not measurably convert 9 alpha FF to 9 alpha FE, but do rapidly convert 9 alpha FE into 9 alpha FF. Reflecting this negligible conversion of 9 alpha FF to 9 alpha FE and the low plasma-protein binding of 9 alpha FF, free urinary 9 alpha FF excretion is much higher than that of F after the same oral dose.(ABSTRACT TRUNCATED AT 400 WORDS)

Other physiological considerations of protective mechanisms of mineralocorticoid action

Mineralocorticoid receptors (MR) are protected from the effects of endogenous glucocorticoids (GC) in mineralocorticoid (MC) target tissues such as the kidney and the parotid gland. This protection is thought to be provided by 11 beta-hydroxysteroid dehydrogenase (11 beta-OHSD). 11 beta-OHSD metabolizes cortisol (in humans) and corticosterone (B) (in the rat) to cortisone and 11-dehydro-B, their respective inactive dehydro products. We have previously shown that the antinatriuretic actions of the MC deoxycorticosterone (DOC) are amplified in carbenoxolone (CBX) treated adrenalectomized (ADX) rats. CBX is believed to inhibit 11 beta-OHSD activity; DOC, however, is not a substrate for this enzyme. We now report on 11-desoxycortisol (11-desoxy-F) and 2 alpha-methylcortisone, substances which possess no intrinsic antinatriuretic activity, are not metabolized by 11 beta-OHSD and yet cause Na+ retention in CBX-treated ADX rats. Given that none of the above steroids are substrates for 11 beta-OHSD it is unlikely that the inhibition of this enzyme is involved in the unmasking of the Na+ retention observed when these substances are given to CBX-treated animals. These results provide further evidence for an additional protective mechanism, that protects MR from the inappropriate binding of excessive amounts of endogenous MCs.