Dehydroepiandrosterone (DHEA) and the menopause: an update.

Since we last reviewed this topic in 2001, considerably more information about dehydroepiandrosterone (DHEA) has accrued, but this has not necessarily left us any wiser about the use of this steroid in postmenopausal women. There is no further evidence that DHEA supplementation is likely to be useful in the prevention of cardiovascular disease or cognitive impairment, or in the promotion of wellbeing. Evidence has, however, accumulated for beneficial effects of DHEA on osteoporosis, both in postmenopausal women and in patients receiving long-term glucocorticoid therapy. What is also emerging is a link between low DHEA levels and cardiovascular risk, and between high DHEA levels and breast cancer risk. In fact, the benefits and adverse effects of DHEA administration in postmenopausal women increasingly resemble those of conventional hormone replacement therapy. Overall, we conclude that DHEA is not currently to be recommended for therapeutic use in the majority of postmenopausal women. However, DHEA supplementation may be of benefit in two specific groups of women: those with the lowest circulating levels of DHEA; and those for whom osteoporosis is a particular problem.

Intra-adrenal mechanisms in the response to chronic stress: investigation in a rat model of emotionality.

The exploratory behaviour of the genetically derived Maudsley rat model of emotionality has been well characterized. Maudsley reactives (MR) present with more 'anxious-like' behaviour than Maudsley nonreactives (MNR). Although this behaviour is assumed to be associated with altered adrenocortical function, the few studies addressing this issue have produced inconsistent findings. We therefore set out to investigate the adrenal endocrinology of the MR and MNR strains. Control Wistars, the ancestors of the Maudsleys, have been used for the first time to set the baseline for all the experiments carried out. It was found that the MNR strain had a significantly blunted adrenocorticotrophic hormone (ACTH) response to restraint stress compared with Wistars, but a normal corticosterone response. Conversely, the MR had a significantly exaggerated ACTH response to restraint stress, but a normal corticosterone response. This finding suggested that the MR adrenal is less sensitive to ACTH than the MNR. This was confirmed by investigating the corticosterone dose-response to ACTH in adrenals from the two strains incubated in vitro. Several possible intra-adrenal regulators were investigated, but the only significant molecular difference in the adrenal glands from the two strains was the level of expression of neuropeptide Y (NPY), which is known to be a stress-responsive peptide in the adrenal. We propose that intra-adrenal NPY is responsible for blunting adrenocortical responses to ACTH stimulation in the MR strain. The observed changes in adrenal NPY suggest that this rat strain may serve as a model of chronic stress, with the MR phenotype representing maladaptation.

Effects of endocrine-disrupting chemicals on adrenal function.

Considering the wide range of chemicals known to disrupt adrenal function and the physiological importance of the adrenal cortex, it is surprising that endocrine disruption of the adrenal gland has not been more widely researched. The chemical nature of adrenal disruptors is highly varied, and there are features of the adrenal structure and function, which render it particularly vulnerable to toxic attack. However, the homeostatic mechanisms inherent in the hypothalamo-pituitary-adrenal axis mean that only the most catastrophic effects are recognized as adrenal disruption, such as in the case of etomidate. In order to detect potentially significant but milder forms of toxic disruption of adrenal function a new approach is needed; this requires the use of more sophisticated approaches than simply measuring one hormone at one time point. New methodologies are also needed, such as the use of human adrenal cell lines for the screening of toxins and for mechanistic investigation of adrenal disruptors. This review focuses on mechanisms of adrenal toxicity and on the challenges facing researchers in this important field.

A systematic review of the scientific evidence for the efficacy of a palliative care approach in advanced dementia.

BACKGROUND: Patients with dementia often receive poor end-of-life care, with inadequate pain control and without access to the palliative care services that patients with cancer are offered. This has been identified as an area of need in recent UK. Government reports and by the Alzheimer's Society (UK). Our objective was to perform a systematic review of the scientific literature regarding the efficacy of a palliative care model in patients with dementia. METHODS: A systematic review was carried out to identify controlled trials that investigated the efficacy of palliative care in patients with dementia. Data sources included were Medline, EMBASE, PsycINFO, CINAHL, British Nursing Index, AMED, Cochrane Database of Systematic Reviews, Web of Science, Cochrane Central Register of Controlled Trials, International Standard Randomised Controlled Trial register, the NHS Economic Evaluation Database and the System for Information on Grey Literature in Europe. Other data was sourced from hand searches of papers identified on electronic databases and review articles. RESULTS: The search identified 30 review articles, but only four papers were eligible for full appraisal and only two of these met the full criteria for inclusion. These papers gave equivocal evidence of the efficacy for a palliative model of care in dementia. CONCLUSION: Despite the increased interest in palliative care for patients with dementia there is currently little evidence on which to base such an approach. This may in part be due to the ethical difficulties surrounding such research, prognostic uncertainty in clinicians and the lack of clear outcome measures for patients who are unable to express their needs or wishes. Further systematic research is urgently needed to educate an important and developing area of clinical practice.

Affective modulation of the startle response in depression: influence of the severity of depression, anhedonia, and anxiety.

BACKGROUND: The amplitude of the startle reflex response is known to be influenced by the concomitant presentation of affect-toned material--if it is positive affect-toned, the reflex is inhibited, and if it is negative affect-toned, the reflex is augmented. Abundant evidence demonstrates the utility of the affect-startle paradigm as a significant tool for measuring both positive and negative emotions. We applied this paradigm to study emotional reactivity in depression, particularly in relation to symptoms of depression, anhedonia, and anxiety. METHODS: Depressed patients (22) and controls (22) were shown a series of film clips, consisting of two clips with positive valence, two with negative valence, and two with relatively neutral valence. The startle response was measured in reaction to the acoustic startle-eliciting stimuli presented three times binaurally during each clip. RESULTS: Highly depressed and anhedonic patients, relative to controls, showed a reduced mood (self-ratings) and a lack of startle modulation in response to affective film clips whereas patients relatively low on depression/anhedonia displayed a reduced mood only with pleasant clips and a normal pattern of affective startle modulation. Anhedonia and depression were highly positively correlated but neither correlated with anxiety. Anxious patients displayed larger reflexes across all clips and showed a reduced mood modulation with pleasant, but not unpleasant, clips. LIMITATIONS: The large majority of patients was medicated with antidepressants which may have influenced the results. CONCLUSIONS. Reactivity to pleasant stimuli is diminished in patients suffering from low levels of depression and/or anhedonia, but reactivity even to unpleasant stimuli seems compromised at high levels of depression and/or anhedonia. Anxiety is associated with hyperstartle responding.

Aldosterone secretion by the rat adrenal cortex is stimulated by the activation of protease-activated receptor 1.

Stimulation of aldosterone by a serine protease, trypsin, was first reported in 1982, although the mechanism of this effect was unclear. Recently, a family of protease-activated receptors (PARs) has been described and four members of the family characterised and cloned, including the previously recognised thrombin receptor. This study investigated whether PARs mediate the action of trypsin on aldosterone secretion. Using intact rat adrenal capsular tissue, thrombin was found to increase aldosterone secretion, and the effects of trypsin on aldosterone secretion were confirmed. Both trypsin and thrombin were shown to activate phospholipase C, as measured by an increase in inositol triphosphate turnover by adrenal capsular tissue. It was also shown that U73122, a phospholipase C inhibitor, attenuated the aldosterone response to trypsin. These effects were consistent with the activation of a PAR. Northern blot analysis revealed the presence of mRNA encoding PAR-1, but not PARs-2, -3 or -4 in the adrenal capsule/zona glomerulosa. Messenger RNA encoding PAR-1 was increased by dietary sodium depletion, consistent with previous reports of an increased response to trypsin after sodium depletion. These data suggest that the actions of trypsin on aldosterone secretion are mediated by PAR-1.

Enhanced startle reactions to acoustic stimuli in patients with obsessive-compulsive disorder.

OBJECTIVE: Anxiety states induced experimentally or occurring naturally potentiate the startle reflex elicited by sudden sensory stimuli in both animals and human beings. The authors investigated whether patients with obsessive-compulsive disorder (OCD) show exaggerated startle reactions to acoustic probes, especially during negative-affect-toned stimuli, compared with healthy subjects. METHOD: Ten patients with OCD and 10 age- and sex-matched comparison subjects were shown a series of film clips. Two of the film clips had positive valence, two had negative valence, and two had relatively neutral valence. The subjects' eyeblink startle response was measured in reaction to startle-eliciting stimuli presented three times binaurally during each film clip. RESULTS: Patients with OCD produced larger startle reflexes and shorter latencies to onset of startle response than the comparison subjects over the entire session. CONCLUSIONS: Patients with OCD were excessively responsive to startle-eliciting stimuli. This effect may be associated with the development or maintenance of OCD.

DHEA deficiency syndrome: a new term for old age?

Dehydroepiandrosterone (DHEA) is a steroid secreted by the adrenal cortex, with a characteristic, age-related, pattern of secretion. The decline of DHEA concentrations with age has led to the suggestion that old age represents a DHEA deficiency syndrome and that the effects of ageing can be counteracted by DHEA 'replacement therapy'. DHEA is increasingly being used in the USA, outside medical supervision, for its supposed anti-ageing effects. This commentary weighs the evidence for the existence of a DHEA deficiency syndrome and considers the value of DHEA 'replacement therapy'.

Effects of metyrapone on hepatic cortisone-cortisol conversion in the rat.

In previous studies in human subjects metyrapone has been found to exert significant extra-adrenal effects, consistent with an effect on the 11-reductase activity of 11beta-hydroxysteroid dehydrogenase (11beta-HSD). In the present study the effects of metyrapone on cortisone metabolism by rat liver microsomes were investigated. Aliquots of microsomal preparations were incubated with NADPH cofactor and different concentrations of cortisone for a range of time intervals up to 30 min. The products of the reaction were extracted with ethyl acetate and separated using thin-layer chromatograph. Cortisol was estimated by radioimmunoassay. There was a linear increase in cortisol formation over the first 150 sec of the reaction. Over this time period metyrapone had no effect on the rate of the reaction. When the reaction was allowed to proceed for 30 min, however, metyrapone caused a 50% decrease in the amount of cortisol formed. These data suggest that metyrapone may alter cortisone-cortisol conversion by directly interacting with 11beta-HSD but in this system metyrapone does not appear to have the characteristics of a conventional enzyme inhibitor.

11Beta-HSD and 17beta-HSD as biological markers of depression: sex differences and correlation with symptom severity.

There is growing interest in the hydroxysteroid dehydrogenases (HSDs) as local modulators of hormone action. We have studied urinary steroid profiles from nine men and nine women with Major Depression to determine whether 11beta-HSD and 17beta-HSD activity are altered. Urinary steroid profiles were determined by high resolution gas chromatography. The ratio of 11-oxo over 11beta-hydroxy metabolites of cortisol was used as the index of 11beta-HSD activity and the ratio of dehydroepiandrosterone (DHA) over androstenediol-17beta was used as the index of 17beta-HSD activity. Symptom severity was assessed using the Hamilton Depression Rating Scale (HDRS). None of the measures of cortisol production, 9 AM plasma cortisol, 24 hour urinary free cortisol or 24 hour total urinary cortisol metabolites, correlated with HDRS in either men or women. 11Beta-HSD activity was altered and correlated with symptom severity in depressed women (r=0.688, p<0.05) but not men (r=0.132). In both depressed men and women, 17beta-HSD activity was altered and correlated with HDRS scores (r=-0.796, p<0.05 and r=0.688, p<0.05 respectively). However, although the ratio was changed in the same direction in depressed men and women. the correlation with symptom severity was positive in women but negative in men. We conclude that markers of subtle change such as these may prove more useful and informative than gross changes in plasma cortisol in depression.

Sex differences in the human metabolism of cortisol.

Sex differences in steroid metabolism have been clearly demonstrated in animal studies, but few studies have addressed this question in the human. Our preliminary studies suggested human sex differences in both cortisol production and metabolism. We therefore looked in more detail at indices of cortisol metabolism derived from 24 hour urinary steroid profiles in a group of 20 men and 20 women who were age-matched, drug-free and had no endocrine disorder. Steroid analysis was by high resolution gas chromatography. Men excreted more total cortisol metabolites (7620 +/- 620 v 4750 +/- 380 micrograms/24 h, p < 0.001), 11-oxo metabolites of cortisol (11-oxo FM, 4320 +/- 400 v 2890 +/- 250 micrograms/24 h, p < 0.001) and 11 beta-hydroxy metabolites of cortisol (11-OH FM, 3290 +/- 240 v 1860 +/- 140 micrograms/24 h, p < 0.001). These differences remained significant when corrected for body surface area. The ratio of 11-oxo FM/11-OH FM, an index of 11 beta-hydroxysteroid dehydrogenase (11-HSD) activity, was higher in women (1.57 +/- 0.07 v 1.31 +/- 0.06, p < 0.01). The ratios of 5 alpha/5 beta and 20-oxo/20-OH metabolites of cortisol were both higher in men (1.07 +/- 0.15 v 0.58 +/- 0.04, p < 0.01, and 2.78 +/- 0.06 v 2.27 +/- 0.11, p < 0.01), while the ratio of 20 alpha/20 beta metabolites of cortisol was higher in women (1.79 +/- 0.13 v 1.32 +/- 0.06, p < 0.01). We conclude that there are considerable sex differences in both the production and metabolism of cortisol in healthy men and women. In particular, the data are consistent with a sex difference in 11-HSD activity, with relatively greater conversion of cortisol to cortisone in women.

Evidence for independent modulation of human 11-HSD and 5 alpha/5 beta reductase activities.

The increased ratio of 5 alpha to 5 beta reduced steroids associated with apparent mineralocorticoid excess (AME) may be a necessary consequence of altered 11 beta-hydroxysteroid dehydrogenase (11-HSD) activity. In order to test this hypothesis we have compared changes in 11-HSD activity and 5 alpha/5 beta reduction in a variety of clinical and experimental conditions. The ratio of 11-oxo/11 beta-hydroxy metabolites of cortisol (11-oxo/11-OH FM) was used as an index of 11-HSD activity and the ratio of allotetrahydrocortisol/ tetrahydrocortisol (allo THF/THF) was used as an index of 5 alpha/5 beta reduction. Ratios were derived from 24 hour urinary steroid profiles measured by high resolution gas chromatography. The clinical conditions studied were Cushing's Syndrome, Major Depression and hirsutism. In each study, the patient group were compared with age-matched healthy controls. For the experimental conditions, subjects treated with either hydrocortisone, dexamethasone, metyrapone or finasteride acted as their own controls. No consistent relationship was found between changes in the ratios of 11-oxo/11-OH FM and allo THF/THF. We conclude that there is no evidence of consistent metabolic interaction between 11-HSD and 5 alpha/5 beta reductase activities under a wide range of conditions. Furthermore, the patterns of metabolic changes seen in these conditions are no less characteristic, although more subtle, than the well-documented metabolic changes seen in inborn errors of steroid metabolism.

The relationship between the effects of metyrapone treatment on depressed mood and urinary steroid profiles.

In order to investigate mechanisms by which the adrenal 11 beta-hydroxylase inhibitor metyrapone might exert its antidepressant effect, we used gas chromatography to analyse the 24 h urinary steroid profiles from six females with major depression taking part in a trial of metyrapone (2-4 g/day) as an antidepressant. Due to concurrent administration of hydrocortisone (30 mg/day), plasma cortisol levels were not significantly reduced. Treatment with metyrapone resulted in greatly increased urinary excretion of 11-deoxy corticosteroids, including the GABA-modulatory steroid tetrahydro-11-deoxycorticosterone (from 68 +/- 34 to 219 +/- 75 micrograms/24 h, p < .05). Metyrapone also had multiple extra-adrenal effects on corticosteroid metabolism, including inhibition of the peripheral conversion of cortisone to cortisol as demonstrated by a significant decrease in the ratio of 11 beta-hydroxy/11-oxo metabolites of cortisol (from 0.81 +/- 0.08 to 0.46 +/- 0.04, p < .01). The decreased Montgomery-Asberg Depression Rating Scale scores seen during treatment with metyrapone did not correlate with changes in plasma cortisol, but did correlate significantly with total 11-deoxycortisol metabolites (r = 0.778, n = 12, p < .01). We conclude that, in addition to decreased cortisol synthesis, increased secretion of cortisol precursors and reduced local bioavailability of cortisol may play a role in the antidepressant effect of metyrapone.

Extra-adrenal effects of metyrapone include inhibition of the 11-oxoreductase activity of 11 beta-hydroxysteroid dehydrogenase: a model for 11-HSD I deficiency.

BACKGROUND AND OBJECTIVE: Previous studies suggesting effects of metyrapone on extra-adrenal corticosteroid metabolism have involved significant alterations in plasma cortisol. We have therefore studied effects of metyrapone on urinary excretion of steroids in a group of patients treated concurrently with hydrocortisone so that changes in plasma cortisol were minimized. DESIGN: Replacement doses of hydrocortisone (30 mg/day) were given concurrently with metyrapone (2-4 g/day) for 2 weeks. Blood samples were taken and 24-hour urinary steroid collections were made at baseline and after 1 and 2 weeks of treatment. PATIENTS: Subjects were 6 female patients with major depression from a trial of metyrapone as an antidepressant. MEASUREMENTS: Urinary steroid profiles were measured by gas chromatography; plasma cortisol and urinary free cortisol were measured by fluorescence immunoassay. RESULTS: Plasma cortisol levels were not significantly decreased by treatment, while excretion of 11-deoxycortisol metabolites increased eightfold after 2 weeks indicating that concurrent hydrocortisone administration had not suppressed the adrenal. Ratios reflecting 11 beta-hydroxy/11-oxo metabolites of cortisol were significantly decreased, consistent with inhibition of the 11-oxoreductase activity of 11 beta-hydroxysteroid dehydrogenase (11-HSD). Other changes included significant decreases in the rates of 5 alpha vs 5 beta and of 20 alpha vs 20 beta reduction of corticosteroids. CONCLUSIONS: Metyrapone has multiple effects on extra-adrenal corticosteroid metabolism and is the only agent we know of which selectively inhibits 11-oxoreductase. Metyrapone thus provides a model for 11-HSD I deficiency and a tool for in-vitro studies of cortisol-cortisone interconversion. The results also suggest mechanisms whereby corticosteroid effects can be regulated separately from corticosteroid synthesis.

Steroid sequestration and tightly bound oestrogen-protein complexes in human breast tumours and a breast cancer cell line.

Homogenates of breast tumours taken at surgery were prepared in phosphate-buffered medium in the presence or absence of the protease inhibitors N-alpha-p-tosyl-L-arginine methyl ester (TAME, 10 mM) or soy bean trypsin inhibitor (STI, 1 mg/ml). Aliquots (0.25 ml) were incubated in 5 ml medium, with the addition of excess trypsin (2 mg/ml) to experimental flasks. Oestrogen was measured by means of a radioreceptor assay (RRA) based on rat or human uterine cytosolic oestradiol receptor. In oestrogen receptor positive (ER +ve) tumour homogenates, TAME decreased while STI increased ethyl acetate extractable oestrogen in these preparations. The addition of trypsin enhanced yields of oestrogen in the TAME, but not in the STI or control (no inhibitor) preparations. None of these treatments affected RRA detectable oestrogen in homogenates of ER -ve tumours. Suspensions of ZR-75-1 cells, prepared in Krebs Ringer bicarbonate (KRBG) incubated with trypsin also gave greatly enhanced yields of extractable oestrogen. Fractionation of oestrogens from both tumour homogenates and from the cell line showed coincidence of RRA detectable steroid with oestradiol and oestrone, and, particularly in trypsin flasks, very non-polar components were also found. In the cell-line extracts, HPLC fractionation combined with specific radioimmunoassays confirmed the presence of both oestradiol and oestrone. The major extracted component was oestrone. The data suggest the existence within breast tumour tissue of sequestered pools of steroid requiring proteolytic action for their release. One possibility, consistent with reports in the literature, is that the steroids may themselves be directly conjugated to protein. Their presence in ER +ve but not ER -ve tumours strongly suggests some relationship to the development of hormone-sensitive disease. Alternatively, the phenomenon may be associated with the rigid compartmentalization of the paracrine function of the tissue.

Effects of protease inhibitors on adenylate cyclase activation and aldosterone production in rat adrenal zona glomerulosa cells.

It has been shown that serine proteases are involved in aldosterone and 18-hydroxycorticosterone production by the rat adrenal zona glomerulosa in response to a variety of stimulants. From evidence presented for various tissues, including the rat adrenal cortex, the observation that adenylate cyclase can be activated by proteolytic enzymes and inhibited by protease inhibitors has led to the suggestion that serine proteases may also be involved in the hormonal stimulation of adenylate cyclase. In studies designed to test this hypothesis using protease inhibitors, only high concentrations (greater than 10(-4) M) of TAME (p-tosyl-L-arginine methyl ester) inhibited ACTH stimulated steroid and cAMP production in rat adrenal glomerulosa cells. TPCK (tosyl-L-phenylalanine chloromethylketone) and TLCK (tosyl-L-lysine chloromethylketone) were found to have a similar effect at very high concentrations (10(-2) M) but had no effect at the serine protease inhibitory concentration of 5 X 10(-6) M. Other protease inhibitors tested had no effect on ACTH-stimulated cAMP but the inhibitory effect of high concentrations of protease inhibitors on ACTH-stimulated adenylate cyclase was duplicated by the polyanion dextran sulphate. The results suggest that the inhibitors act through non-specific membrane effects and that proteases are not involved in the activation of zona glomerulosa adenylate cyclase by ACTH. In view of these findings it is concluded that a more rigorous approach should be applied to the use of protease inhibitors in whole cell systems, and that the concept of hormonal activation of adenylate cyclase via proteolytic events, which is based on studies with such inhibitors, should be reconsidered.

The relationship between tissue preparation and function; methods for the study of control of aldosterone secretion: a review.

The study of the control of aldosterone synthesis and secretion by the rat adrenal gland has over the past thirty years involved the application of many different in vivo and in vitro techniques. In this review the relationship between the data that each of these methods has produced is compared. There are striking differences in overall steroid production rates, and in the qualitative nature of the steroid profile which the various methods produce. In particular, aldosterone is secreted at higher rates in vivo, and when whole tissue preparations are used in vitro, than in incubations of isolated glomerulosa cells. In addition, while corticosterone is a major product of glomerulosa tissue in vitro, the available evidence suggests that it is not a major glomerulosa product in vivo.

Factors affecting the trypsin induced release of aldosterone in rat adrenal zona glomerulosa tissue.

The yields of aldosterone obtained during incubation of whole adrenal capsule tissue from the rat (consisting of the connective tissue capsule itself, all of the glomerulosa tissue, and some fasciculata) cannot apparently be accounted for by the gland's capacity for de novo synthesis of this steroid. Recent studies with proteolytic enzymes and inhibitors suggest that in part aldosterone output may result from the activation of proteolytic events which release aldosterone from a sequestered intraglandular pool. These proteolytic events are mimicked by the addition of trypsin to whole tissue incubations in vitro. Experiments were carried out to determine what factors may govern the size of such intraglandular steroid pools. The most remarkable effect was that prior sodium depletion greatly enhanced the yield (2-3-fold) of aldosterone on subsequent incubation of adrenal capsules with trypsin, to an extent far greater than the increase in basal (non trypsin induced) aldosterone output in this tissue. Although betamethasone (20 micrograms/ml in drinking water) and the converting enzyme inhibitor captopril (7.2 mg/day) eliminated trypsin releasable steroid in control animals, they had no effect on the enhanced levels of trypsin releasable steroid seen with sodium depletion. The data suggest that trypsin releasable steroid pools are variable in accordance with the physiological requirements of the animal, particularly in sodium depletion.