The effects of infusions of ring-A-reduced derivatives of aldosterone on the antinatriuretic and kaliuretic actions of aldosterone

Neuropsychological Assessment in Elderly Men with Benign Prostatic Hyperplasia Treated with Dutasteride

BACKGROUND AND OBJECTIVE

Benign prostatic hyperplasia (BPH) is a common disease found in elderly men and 5α-reductase (5α-R) inhibitors are a commonly used treatment option. 5α-reduced steroids are compounds that play a role in several functions across different organs and systems. In the adult brain, 5α-R accounts for neuroactive steroid production. Whether neuropsychological impairment could be due to dutasteride treatment, a 5α-R inhibitor affecting the production of dihydrotestosterone (DHT), is still unknown. The aim of our study was to investigate neuropsychological features in men receiving dutasteride.

METHODS

The Mini Mental State Examination (MMSE), the Clock Drawing Test (CDT), the Frontal Assessment Battery (FAB), the Hamilton Anxiety Rating Scale (HAM-A), the Beck Depression Inventory second edition (BDI-II) and the Short Form-12 (SF-12) questionnaire were administered in order to explore both cognitive impairment and psychological features.

RESULTS

In a sample of BPH patients (n = 40; mean age 71.4 ± 7.4 years), men receiving dutasteride showed no significant differences during the neuropsychological assessment in comparison with an age-matched control group, consisting of BPH men not receiving dutasteride (p < 0.05). No significant associations were recorded between treatment duration and any of the administered tests.

CONCLUSIONS

This is the first study investigating the neuropsychological features in dutasteride users. Our preliminary data are consistent with the safety of dutasteride under a mental profile.

The amygdala: site of genomic and nongenomic arousal of aldosterone-induced sodium intake

BACKGROUND.: Mineralocorticoids act on the brain to influence sodium intake, and they do so via intracellular type I receptors and possibly also via a direct membrane action, as they do in the kidney. One brain area implicated by lesion studies investigating the regulation of sodium appetite aroused by adrenal steroids is the amygdala.

METHODS

To examine the mechanism by which mineralocorticoids act in the amygdala to arouse salt intake via a genomic and or membrane mode of action, rats were bilaterally fitted with cannulae directed to terminate in the amygdala. The genomic action of mineralocorticoids in arousing sodium intake was investigated by the administration of antisense oligodeoxynucleotides (ASDNs) against the mineralocorticoid receptor, and its effects on deoxycorticosterone (DOCA)-induced sodium intake over the course of several days was examined. The nongenomic action of mineralocorticoids on sodium intake was investigated by implantation into the amygdala of DOCA, aldosterone (ALDO), or their A-ring-reduced tetrahydro derivatives, 15 minutes prior to access to saline. Sodium intake was monitored immediately thereafter.

RESULTS

Treatment of rats in the amygdala with ASDN against the mineralocorticoid receptor inhibited DOCA-induced sodium intake, whereas ASDN against the glucocorticoid receptor or sense/scrambled sequences had no effect. DOCA and ALDO increased saline intake within 15 minutes after steroid application. Similarly, the application of A-ring-reduced 3beta,5beta tetrahydroaldosterone and 5 alpha-tetrahydrodeoxycorticosterone produced the same increases in sodium intake.

CONCLUSIONS

Together, the data imply that adrenal steroids, in addition to acting through classic cytosolic receptors, may also act on membrane receptor systems, producing rapid changes in behavior.

Intracerebroventricular Administration of Mineralocorticoid Receptor Antisense Oligonucleotides Attenuates Salt Appetite in the Rat

The anterior ventral third ventricle (AV3V) region of the brain contains high concentrations of mineralocorticoid receptors (MR) and glucocorticoid receptors (GR) that are important in the maintenance of body fluid and electrolyte balance as well as other physiological processes. Daily intracerebroventricular pulse injections of MR antisense oligonucleotides significantly suppressed deoxycorticosterone acetate (DOCA) induced salt appetite in a dose-related manner. Similar administration of GR antisense or scrambled/sense oligonucleotide into the third ventricle failed to inhibit salt appetite. Salt appetite aroused after adrenalectomy was not suppressed by MR antisense oligonucleotide treatments but was suppressed by an antisense oligonucleotide directed against the angiotensin II AT1 receptor subtype. Receptor binding analysis demonstrated that MR and GR oligonucleotide treatments each reduced their respective receptor subtypes. Finally, although GR antisense oligonucleotide treatment was ineffective in suppressing DOCA-induced salt appetite, this treatment did increase stress induced corticosterone release as well as delayed the recovery of corticosterone to basal levels after stress.

Reduced aldosterone metabolites in hypertension

Significant quantities of 5 alpha and 5 beta-Ring A-reduced metabolites and several polar cytochrome P-450 dependent hydroxylated neutral metabolites of aldosterone (Aldo) (NMA) are soon present in the kidney during the latent period, prior to the expression of Aldo's effects on Na+ and K+. Their levels in the kidney (a) correlate, in a dose-dependent manner, with the magnitude of physiological responses to Aldo in male rats, (b) are lower in the kidneys of females, which show smaller responses to Aldo than males, (c) are lower in the kidneys of males treated with the anti-mineralocorticoid spironolactone, and (d) their synthesis can be regulated by dietary Na+ and K+. Anti-mineralocorticoids completely inhibit synthesis of 5 alpha-reduced metabolites of Aldo in both kidney and toad bladder and of several of the polar hydroxylated NMA in both liver and kidney. 5 alpha-Reduced metabolites and their 2-hydroxylated derivatives possess significant mineralocorticoid activity and their synthesis is increased in rats fed a low Na+ diet and decreased with a high Na+ diet. We have suggested that their synthesis may play a major role in the expression and/or regulation of the individual renal anti-natriuretic and kaliuretic actions of Aldo.

Influence of glucocorticoid on the metabolism of aldosterone in the isolated perfused rat liver and kidney

The effect of glucocorticoid deficiency and excess on the extraadrenal metabolism of D-[4-14C]aldosterone (at 4 nM) was studied by radioimmunoassay and by high-performance liquid chromatography in the isolated perfused liver and kidney of adult Wistar rats. Bilateral adrenalectomy was performed 3 weeks before experiments. In nonadrenalectomized rats, 0.3 mg/kg/day dexamethasone was continuously infused subcutaneously for 1 week before experiments. Adrenalectomy did not affect hepatic or renal metabolism of aldosterone. Dexamethasone treatment did not change the renal handling of aldosterone. However, the hepatic clearance of aldosterone was 19% lower (P less than 0.05) in livers of dexamethasone treated rats than in livers of normal rats. After 5 minutes, perfusate [4-14C]aldosterone metabolites were lower in livers of dexamethasone-treated than in livers of normal rats (P less than 0.05). Similar perfusate levels were then obtained. Radiometabolite peaks with similar relative retention times were found in the hepatic perfusate of all groups. However, the ratio between circulating polar metabolites of aldosterone and the metabolites less polar than tetrahydroaldosterone, after 5 and 15 minutes, was highest in livers of dexamethasone-treated rats. Biliary elimination of 14C was similar in all groups. Significant amounts of conjugated tetrahydroaldosterone were only excreted in the bile of dexamethasone-treated rats. In conclusion, glucocorticoid excess reduced the hepatic clearance of aldosterone and changed the pattern of the hepatic metabolites of aldosterone both in circulation and in bile.