Wiebke Arlt

DHEA treatment: myth or reality?

Dehydroepiandrosterone (DHEA) and its sulfate ester are major secretory products of the human adrenal. Serum DHEA concentrations decline with advancing age and DHEA supplementation in elderly people has been advertized as anti-aging medication. However, such claims are based on experiments in rodents with a fundamentally different DHEA physiology. In humans, DHEA is a crucial precursor of sex steroid biosynthesis and exerts indirect endocrine and intracrine actions following conversion to androgens and estrogens. In addition, it acts as a neurosteroid via effects on neurotransmitter receptors in the brain. DHEA has considerable effects on mood, well-being and sexuality in patients with adrenal insufficiency, and also in those with mood disorders. However, subjects with a physiological, age-related decline in DHEA secretion show little benefit from DHEA administration. Future research should focus on DHEA treatment for adrenal insufficiency, and DHEA administration in both patients receiving chronic glucocorticoid treatment and women with androgen deficiency.

Dhea Replacement in Women with Adrenal Insufficiency—Pharmacokinetics, Bioconversion and Clinical Effects on Well-Being, Sexuality and Cognition

Standard replacement for adrenal insufficiency (AI) consists of glucocorticoids and mineralocorticoids while DHEA deficiency is routinely ignored. Thus, AI represents the ideal pathophysiological model of isolated DHEA deficiency. We investigated the effects of DHEA replacement in 24 women with primary and secondary AI employing a double blind, placebo-controlled, randomized crossover design. A DHEA dose of 50 mg/d was chosen based on preceding single-dose pharmacokinetics and bioconversion studies. Each patient received four months of treatment with DHEA and four months placebo, with a one-month washout period. Measurements included serum steroid hormones, somatotropic parameters and psychometric assessment of well-being, mood, cognition and sexuality. Treatment with DHEA raised the initially low serum concentrations of DHEA, DHEAS, androstenedione, and testosterone into the normal range. DHEA induced a slight increase in serum IGF-I, but only in patients with primary AI, suggesting a growth hormone-mediated effect. DHEA treatment significantly improved overall well-being as well as scores for depression, anxiety, and their physical correlates. Furthermore, DHEA significantly increased both sexual interest and the level of satisfaction with sex. DHEA replacement had no influence on the cognitive performance, which was already on a high level at baseline. In conclusion, DHEA replacement improves well-being and sexuality in women with adrenal insufficiency. If this is due to a direct effect of DHEA on the brain, an indirect effect via increased androgen synthesis, or both, remains to be elucidated. Long-term studies in patients of both sexes are needed to further define the role of DHEA in standard replacement for adrenal insufficiency.

Expression of adrenocorticotrophic hormone receptor mRNA in human adrenocortical neoplasms: correlation with P450scc expression

OBJECTIVEAdrenocorticotrophin (ACTH) is the main hormone‐regulating steroid secretion from the adrenal cortex. The ACTH receptor (ACTH‐R) has recently been cloned, allowing systematic evaluation of its expression and function in adrenal tumorigenesis. We investigated ACTH‐R and P450 side‐chain cleavage enzyme (P450scc) mRNA expression in a variety of neoplastic adrenocortical tissues by Northern blot and reverse‐transcriptase‐PCR (RT‐PCR).

Ectopic ACTH production by a bronchial carcinoid tumour responsive to desmopressin in vivo and in vitro

A desmopressin‐induced ACTH increase has been recently suggested to be specific for pituitary‐dependent Cushings disease. We present the case of a 47‐year‐old woman with Cushings syndrome due to ectopic ACTH production by a bronchial carcinoid. While CRH failed to induce an ACTH or cortisol response, intravenous administration of desmopressin led to a 47% increase in serum ACTH and a 42% increase in serum cortisol concentration. After surgical removal of the tumour, the desmopressin response became negative. In vitro, ACTH production by tumour cells obtained at surgery was also stimulated by desmopressin but not by CRH. Additional receptor mRNA expression studies using RT‐PCR revealed expression of both V2 and V3 vasopressin receptor subtypes in the carcinoid tumour at a level comparable to that recently described in pituitary corticotroph adenomas. This case illustrates that ACTH stimulation by desmopressin is not specific for pituitary‐dependent Cushings syndrome as vasopressin receptor subtypes known to interact with desmopressin may also be found in ectopic tumours producing ACTH.

Influence of oral dehydroepiandrosterone (DHEA) on urinary steroid metabolites in males and females

Oral dehydroepiandrosterone (DHEA) replacement therapy may have a multitude of potential beneficial effects and exerts its action mainly via peripheral bioconversion to androgens (and estrogens). A daily dose of 50-mg DHEA has been shown by us and others to restore low endogenous serum DHEA concentrations to normal youthful levels followed by an increase in circulating androgens and estrogens. As the hepatic first-pass effect may lead to a non physiological metabolism of DHEA after oral ingestion we studied the influence of two single DHEA doses (50 and 100 mg) on the excretion of steroid metabolites in 14 elderly males [age 58.8+/-5.1 years (mean +/- SEM)] with endogenous DHEAS levels <1500 ng/ml and in 9 healthy females (age 23.3+/-4.1 years) with transient suppression of endogenous DHEA secretion induced by dexamethasone (dex) pretreatment (4x0.5 mg/day/4 days). Urinary steroid profiles in the elderly males were compared to the steroid patterns found in 15 healthy young men (age 28.9+/-5.1 years). In the females the results were compared to their individual baseline excretion without dex pretreatment. Urinary steroid determinations were carried out by semiautomatic capillary gas-liquid chromatography. In both genders DHEA administration induced significant increases in urinary DHEA (females: baseline vs. 50 mg vs. 100 mg: 361+/-131 vs. 510+/-264 vs. 1541+/-587 microg/day; males: placebo vs. 50 mg vs. 100 mg: 434+/-154 vs. 1174+/-309 vs. 4751+/-1059 microg/day) as well as in the major DHEA metabolites androsterone (A) and etiocholanolone (Et). Fifty mg DHEA led to an excretion of DHEA and its metabolites only slightly above baseline levels found in young females and in young men, respectively, whereas 100 mg induced clearly supraphysiological values. After 50 mg DHEA the ratios of urinary DHEA metabolites (A/DHEA, Et/DHEA) were not significantly different between elderly males vs. young male volunteers and young healthy females versus their individual baseline levels. In conclusion, an oral dose of 30 to 50 mg DHEA restores a physiological urinary steroid profile in subjects with DHEA deficiency without evidence for a relevant hepatic first-pass effect on urinary metabolites.

Oral glucose tolerance testing but not intravenous glucose administration uncovers hyper-responsiveness of hypothalamo-pituitary-adrenal axis in patients with adrenal incidentalomas.

Modern imaging techniques are detecting adrenal incidentalomas with increasing frequency. Recent data suggests food‐dependent hypercortisolism in a subgroup of patients with bilateral macronodular hyperplasia due to aberrant adrenal responsiveness to gastric inhibitory polypeptide (GIP). We studied the putative influence of food intake on the hypothalamo–pituitary–adrenal (HPA) axis in patients with adrenal incidentalomas and possible mediation by GIP.

Adrenocortical insufficiency in Rhodesian sleeping sickness is not attributable to suramin

Suramin, a polysulphonated naphthylurea used in the treatment of human African trypanosomiasis (HAT), is known to cause adrenocortical insufficiency in doses exceeding the quantity used for treatment of HAT. We have previously reported that Trypanosoma brucei rhodesinese infection causes a combined central and peripheral adrenal insufficiency. To evaluate whether suramin therapy acts as an additional adrenotoxic factor, we assessed adrenocortical function in 72 patients suffering from HAT at different times during treatment with either suramin or melarsoprol by a rapid adrenocorticotropic hormone test. We found a significantly diminished peak cortisol response to stimulation in the acutely ill patients (P = 0.001), indicating impaired adrenocortical function, as well as a high incidence of partial adrenocortical insufficiency (27%). During and after trypanocidal therapy the incidence of partial adrenal insufficiency gradually declined (to 25% and 18% respectively). Stimulated peak cortisol levels did not differ significantly between patients receiving suramin and those given melarsoprol. No correlation was found between serum suramin concentration and the cortisol response to stimulation (r = 0.09, P = 0.47). Thus we conclude that suramin in trypanocidal doses neither causes nor worsens the adrenocortical dysfunction observed in Rhodesian HAT.