post.miyazaki-med.ac.jp

The metabolism of orally administered dehydroepiandrosterone (DHEA) by male and female golden Syrian hamsters was examined by quantification of DHEA and dehydroepiandrosterone sulfate (DHEAS) in gallbladder bile, urine and feces using high-performance liquid chromatography (HPLC). Plasma levels of DHEA and DHEAS were also determined by radioimmunoassay (RIA). After 5 days of oral DHEA administration (100 mg/kg body weight twice a day), RIA showed that plasma levels of DHEA and DHEAS were increased approximately 3-6 and 4-5 times, respectively, compared to controls. More than 95 % of circulating DHEA (S) in the peripheral blood was DHEAS. There was no significant sex difference in DHEAS plasma levels between male and female animals in the DHEA-supplemented group. However, 0.2 - 0.3 % of ingested DHEA was conjugated to DHEAS and excreted in urine by females, whereas less than 0.002 % was excreted in urine by males (p < 0.005). DHEAS was excreted in bile by males after DHEA supplementation, and the sex differences in DHEAS levels observed in bile were statistically significant (male, 18.7 +/- 7.5 vs. female, 5.6 +/- 3.1 micromol/l) (p < 0.005). Small amounts of ingested DHEA were excreted in an unchanged state in feces, and no sex difference was observed. These results suggest that there is a considerable sex difference in the conjugation and excretion of orally administered DHEA in the hamster.

Online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=15002061&dopt=Abstract DHEA [PubMed - in process]

terra.com.br

Dehydroepiandrosterone (DHEA) exerts multiple effects in the rodent central nervous system (CNS), mediated through its nongenomic actions on several neurotransmitter systems, increasing neuronal excitability, modulating neuronal plasticity and presenting neuroprotective properties. It has been demonstrated that DHEA is a potent modulator of GABA(A), NMDA and Sigma receptors. In the present study, we investigated the effect of DHEA on (i) basal- and K(+)-stimulated l-[(3)H]glutamate release from synaptosomes (both in vitro and ex vivo), (ii) synaptosomal l-[(3)H]glutamate uptake (in vitro), and (iii) an inhibitory avoidance task (in vivo). The results indicated that DHEA in vitro increased glutamate release by 57%, and its intracerebroventricular infusion increased the basal-[(3)H]glutamate release by 15%. After 30 min of intraperitoneal administration, DHEA levels in the serum or CSF increased 33 and 21 times, respectively. Additionally, DHEA, intraperitoneally administrated 30 min before training, improved memory for inhibitory avoidance task. Concluding, DHEA could improve memory on an inhibitory avoidance task, perhaps due to its ability to physiologically strength the glutamatergic tonus by increasing glutamate release.

Online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=15006472&dopt=Abstract DHEA [PubMed - in process]




Steroids. 2004 Feb;69(2):137-44.
Antioxidant effects of dehydroepiandrosterone and 7alpha-hydroxy-dehydroepiandrosterone in the rat colon, intestine and liver.

Pelissier MA, Trap C, Malewiak MI, Morfin R.

Laboratoire de Biologie, EA-3199, Conservatoire National des Arts et Metiers, 2 rue Conte, 75003 Paris, France.

This study examined in healthy male Wistar rats the in vivo antioxidant effect of dehydroepiandrosterone (DHEA) and 7alpha-hydroxy-DHEA administered by intraperitoneal injections (50 mg/kg body weight) for 2 or 7 days. Markers of oxidative damage to lipids (thiobarbituric acid-reacting substances, TBARS) and to proteins (protein carbonyls) were assessed in colon, small intestine, and liver homogenates. DHEA and 7alpha-hydroxy-DHEA caused a decrease in body weight. DHEA treatment significantly increased liver, colon, and small intestine cell weights. After 7 days, DHEA exerted an antioxidant effect in all organs studied. In the colon, oxidative damage protection was accompanied by a goblet cell proliferation and increase in acidic mucus production. After 2 days, the antioxidant effect of 7alpha-hydroxy-DHEA was mainly observed in the liver. Nonprotein sulfhydryl groups (mostly glutathione levels) were altered by DHEA in the liver whereas they remained unchanged after 7alpha-hydroxy-DHEA treatment. The results indicate that in healthy animals, DHEA exerts a protective effect, particularly in the colon, by reducing the tissue susceptibility to oxidation of both lipids and proteins. This effect was not limited to a specific tissue, whereas the metabolite 7alpha-hydroxy-DHEA exerted its antioxidant effect towards the two markers of oxidative damage earlier than DHEA, and mainly in the liver.

Online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=15013692&dopt=Abstract DHEA [PubMed - in process]




Endocrinology. 2003 Jan;144(1):253-9.
Dehydroepiandrosterone down-regulates the expression of peroxisome proliferator-activated receptor gamma in adipocytes.

Kajita K, Ishizuka T, Mune T, Miura A, Ishizawa M, Kanoh Y, Kawai Y, Natsume Y, Yasuda K.

The Third Department of Internal Medicine, Gifu University School of Medicine, Tsukasa-machi 40, Gifu 500-8705, Japan.

Dehydroepiandrosterone (DHEA) is expected to have a weight-reducing effect. In this study, we evaluated the effect of DHEA on genetically obese Otsuka Long Evans Fatty rats (OLETF) compared with Long-Evans Tokushima rats (LETO) as control. Feeding with 0.4% DHEA-containing food for 2 wk reduced the weight of sc, epididymal, and perirenal adipose tissue in association with decreased plasma leptin levels in OLETF. Adipose tissue from OLETF showed increased expression of peroxisome proliferator-activated receptor gamma (PPARgamma) protein, which was prevented by DHEA treatment. Further, we examined the effect of DHEA on PPARgamma in primary cultured adipocytes and monolayer adipocytes differentiated from rat preadipocytes. PPARgamma protein level was decreased in a time- and concentration-dependent manner, and DHEA significantly reduced mRNA levels of PPARgamma, adipocyte lipid-binding protein, and sterol regulatory element-binding protein, but not CCAAT/enhancer binding protein alpha. DHEA-sulfate also reduced the PPARgamma protein, but dexamethasone, testosterone, or androstenedione did not alter its expression. In addition, treatment with DHEA for 5 d reduced the triglyceride content in monolayer adipocytes. These results suggest that DHEA down-regulates adiposity through the reduction of PPARgamma in adipocytes.

Online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12488352&dopt=Abstract DHEA

hotmail.com

Dehydroepiandrosterone (DHEA) and its sulfate (DHEAS) are suggested to be important neurosteroids. We investigated steroid sulfatase (STS) in human temporal lobe biopsies in the context of possible cerebral DHEA(S) de novo biosynthesis. Formation of DHEA(S) in mature human brain tissue has not yet been studied. 17 alpha-Hydroxylase/C17-20-lyase and hydroxysteroid sulfotransferase catalyze the formation of DHEA from pregnenolone and the subsequent sulfoconjugation, respectively. Neither their mRNA nor activity were detected, indicating that DHEA(S) are not produced within the human temporal lobe. Conversely, strong activity and mRNA expression of DHEAS desulfating STS was found, twice as high in cerebral neocortex than in subcortical white matter. Cerebral STS resembled the characteristics of the known placental enzyme. Immunohistochemistry revealed STS in adult cortical neurons as well as in fetal and adult Cajal-Retzius cells. Organic anion transporting proteins OATP-A, -B, -D, and -E showed high mRNA expression levels with distinct patterns in cerebral neocortex and subcortical white matter. Although it is not clear whether they are expressed at the blood-brain barrier and facilitate an influx rather than an efflux, they might well be involved in the transport of steroid sulfates from the blood. Therefore, we hypothesize that DHEAS and/or other sulfated 3beta-hydroxysteroids might enter the human temporal lobe from the circulation where they would be readily converted via neuronal STS activity.

Online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=15056284&dopt=Abstract DHEA




Mol Cell Endocrinol. 2004 Feb 12;214(1-2):127-35.
IGF-I signaling prevents dehydroepiandrosterone (DHEA)-induced apoptosis in hypothalamic neurons.

Lin SY, Cui H, Yusta B, Belsham DD.

Department of Physiology, University of Toronto, Medical Sciences Building 3247A, 1 King's College Circle, Toronto, Ont, Canada M5S 1A8.

Dehydroepiandrosterone (DHEA) is synthesized in the brain, but whether DHEA is involved in modulating neuronal cell survival is not yet fully understood. Herein we show that when deprived of trophic support, GT1-7 hypothalamic neurons undergo apoptosis following exposure to DHEA, as demonstrated both by morphological and biochemical criteria. This proapoptotic effect appeared to be specific to DHEA itself, and not through conversion of DHEA to other steroids such as androgen or estrogen. Importantly, we determined that IGF-I protects GT1-7 neurons from DHEA-induced cell death. DHEA-induced apoptosis was associated with increased activation of caspase 3 and decreased PARP, which were both attenuated with addition of IGF-I. Addition of DHEA prevented phosphorylation of both Akt and glycogen synthase kinase-3 beta (GSK-3beta), downstream effector molecules of the phosphatidylinositol 3-kinase (PI3K) pathway. Further IGF-I was able to sustain Akt activity and thus preventing GSK-3beta activation in the presence of DHEA. On the other hand, the MAP kinases, ERK, p38, and JNK, were not affected by DHEA. These findings suggest that in GT1-7 hypothalamic neurons, DHEA acts detrimentally to induce cell death and IGF-I is able to rescue the neurons by preserving the activity of Akt, and therefore maintaining the proapoptotic kinase GSK-3beta, in a phosphorylated catalytically inactive state.

Online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=15062551&dopt=Abstract DHEA

ykh.gr.jp

Dehydroepiandrosterone (DHEA) is known to improve hyperglycemia in diabetic db/db mice that are obese and insulin resistant. In a previous study, we reported that DHEA suppresses the elevated hepatic gluconeogenic glucose-6-phosphatase (G6Pase) activity and gene expression in C57BL/KsJ-db/db mice. In the present study, we evaluated the total amount of gluconeogenesis using NaH[(14)C]CO(3) and hepatic glucose production using fructose as a substrate in primary cultured hepatocytes. Despite hyperinsulinemia, the glucose production of db/db mice in the total body and hepatocytes was elevated as compared to their heterozygote littermate C57BL/KsJ-db/+m mice. Administration of DHEA significantly decreased the blood glucose level and increased the plasma insulin level in db/db mice. Administration of DHEA decreased the elevated total body and hepatic glucose production in db/db mice. In addition, the glucose production in the primary cultured hepatocytes of db/db mice was decreased significantly by the direct addition of DHEA or DHEA-S to the medium. These results suggest that administration of DHEA suppresses the elevated total body and hepatic glucose production in db/db mice, and this effect on the liver is considered to result from increased plasma insulin and DHEA or DHEA-S itself.

Online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=15081573&dopt=Abstract DHEA




Biol Reprod. 2004 Apr 14 [Epub ahead of print]
Functional Luteinizing Hormone/Chorionic Gonadotropin Receptors in Human Adrenal Cortical H295R Cells.

Rao CV, Zhou XL, Lei ZM.

Previous studies have suggested that activation of normal human adrenal and adrenal tumor luteinizing hormone (LH)/chorionic gonadotropin (hCG) receptors results in an increased secretion of steroid hormones. Since it is not feasible to test this suggestion on normal human adrenal cells, we used human adrenal cortical carcinoma H295R cells, which are similar in some respects to normal adrenal cortical cells. These cells contained LH/hCG receptor transcripts and receptor protein that can bind (125)I-hCG in a hormone-specific manner. Culturing the cells with highly purified hCG resulted in a time- and dose-dependent significant increase in DHEAS secretion as compared with the controls. The DHEAS response was hormone as well as steroid specific. Since hCG treatment did not increase DHEA secretion, we suspected that the hCG might increase DHEA sulfotransferase (ST). Consistent with this possibility, hCG treatment increased steady state DHEA-ST mRNA levels. The hCG effects require its receptors, as inhibition of their synthesis by treatment with antisense phosphorothioate oligodeoxynucleotides (ODN) made from the LH/hCG receptor sequence, resulted in loss of DHEA-ST and DHEAS responses. The findings that a) hCG treatment increased cAMP levels and activated PKA, b) 8-bromo cAMP mimicked hCG and c) blocking PKA activation prevented hCG as well as 8-bromo cAMP from increasing both DHEA-ST mRNA and DHEAS levels, suggested that cyclic AMP/protein kinase A signaling was involved in the hCG actions. In conclusion, H295R cells contain LH/hCG receptors, which are coupled to increasing DHEAS secretion through upregulating ST enzyme mRNA level. This action is mediated by cAMP/PKA signaling pathway. These findings support the concept that adrenals function in normal and pathological conditions could be influenced by LH and hCG.

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J Steroid Biochem Mol Biol. 2004 Mar;88(3):261-4.
Dehydroepiandrosterone (DHEA) and its sulfate (DHEAS) inhibit the apoptosis in human peripheral blood lymphocytes.

Takahashi H, Nakajima A, Sekihara H.

The Third Department of Internal Medicine, School of Medicine, Yokohama City University, 3-9 Fuku-ura, Kanazawa, Yokohama, Japan.

Background: Dehydroepiandrosterone (DHEA) and DHEA-sulfate (DHEAS) are the major steroid hormones secreted by the adrenal gland. Administration of DHEA has been reported to have beneficial effects on aging, diabetes, and atherosclerosis. Apoptosis is a normal physiologic process that occurs during embryonic development as well as in the maintenance of tissue homeostasis. In this study, we examined the suppressive effect of DHEA(S) on staurosporine-induced apoptosis in human peripheral blood lymphocytes (PBL). Methods: Apoptosis was induced in human PBL with staurosporine and measured by flow cytometry utilizing Annexin V and propidium iodide (PI) staining. The quantity of FITC+/PI- cells corresponded to early apoptosis, while that of FITC+/PI+ cells corresponded to late apoptosis or secondary necrosis. Results: The fraction of staurosporine-induced early apoptosis but not that of secondary necrosis in PBL was reduced by the treatment with either DHEA or DHEAS. Furthermore, this apoptosis was neither associated with androgen receptor (AR) nor with estrogen receptor (ER). Conclusions: This is the first study showing that DHEA(S) inhibits apoptosis in human PBL through a mechanism independent of either ARs or ERs. DHEA(S) may be a promising chemopreventive drug for aging, diabetes, and atherosclerosis.

Online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=15120419&dopt=Abstract DHEA [PubMed - in process]




Mol Cell Endocrinol. 2004 Apr 15;218(1-2):57-64.
Dehydroepiandrosterone up-regulates resistin gene expression in white adipose tissue.

Kochan Z, Karbowska J.

Department of Biochemistry, Medical University of Gdansk, Debinki 1, 80-211 Gdansk, Poland.

Dehydroepiandrosterone (DHEA), the most abundant steroid hormone in human blood, is considered to be one of fat-reducing hormones. However, the molecular mechanisms underlying DHEA mode of action in obesity has not been fully clarified. The pivotal role in the maintenance of cellular lipid and energy balance is played by peroxisome proliferator-activated receptor alpha (PPARalpha) which acts as transcriptional activator of numerous genes encoding enzymes involved in fatty acid catabolism. Lately published papers suggest that resistin, a low molecular-weight protein produced by adipose tissue, may act as an inhibitor of adipocyte differentiation and could regulate adipose tissue mass. Recent studies have established that the promoter region of the resistin gene contains several putative PPAR response elements. Since DHEA has been characterized as a peroxisome proliferator able to induce hepatic genes through PPARalpha, we hypothesised that DHEA might affect PPARalpha and, subsequently, resistin gene expression in adipose tissue. In order to test this hypothesis, an experiment was performed comparing PPARalpha and resistin gene expression in white adipose tissue (WAT) of male Wistar rats fed standard or DHEA-supplemented (0.6% (w/w)) diet for 2 weeks. DHEA administration to the rats induced PPARalpha and resistin gene expression in WAT (3- and 2.25-fold, respectively; as determined by real-time reverse transcription-polymerase chain reaction (RT-PCR)); reduced body weight, epididymal adipose tissue mass and decreased serum leptin levels. We propose that DHEA may impact on the transcription of resistin gene through a mechanism involving PPARalpha and that an elevated resistin level may lead to an inhibition of adipogenesis and a decrease in adipose tissue m




Proc Natl Acad Sci U S A. 2004 May 25;101(21):8209-14. Epub 2004 May 17.
Dehydroepiandrosterone and allopregnanolone protect sympathoadrenal medulla cells against apoptosis via antiapoptotic Bcl-2 proteins.

Charalampopoulos I, Tsatsanis C, Dermitzaki E, Alexaki VI, Castanas E, Margioris AN, Gravanis A.

Departments of Pharmacology, Clinical Chemistry, and Experimental Endocrinology, School of Medicine, University of Crete, Heraklion 71110, Greece.

The neuroactive steroids dehydroepiandrosterone (DHEA), its sulfate ester DHEA sulfate (DHEAS), and allopregnanolone (Allo), produced by the CNS and the adrenals, appear to exert a protective effect in hippocampal and cortical neuron ischemia- and excitotoxicity-induced injury. We hypothesized that they may also play a protective role on the adrenal medulla, an important part of the sympathetic nervous system, and the tissue adjacent to their primary site of production. DHEA, DHEAS, and Allo protected rat chromaffin cells and the rat pheochromocytoma PC12 cell line, an established model for the study of adrenomedullary cell apoptosis and survival, against serum deprivation-induced apoptosis. Their effects were time- and dose-dependent, with EC(50) 1.8, 1.1, and 1.5 nM, respectively. The antiapoptotic effect of DHEA DHEAS and Allo was compared to that of a long list of structurally related compounds and was found to be structure-specific, confined mainly to conformation 3beta-OH-Delta(5) for androstenes and 3alpha-OH for pregnanes. Indeed, 3-keto, Delta(4), or C7 hydroxylated androstenes and 3beta pregnanes were ineffective. The prosurvival effect of DHEA(S) and Allo was N-methyl-D-aspartate-, GABA(A)-, sigma1-, or estrogen receptor-independent. It involved the antiapoptotic Bcl-2 proteins, their role being sine qua non for their action because Bcl-2 antisense oligonucleotides reversed their effects. Finally, DHEA(S) and Allo activated cAMP response element-binding protein and NF-kappaB, upstream effectors of antiapoptotic Bcl-2 protein expression. They also activated the antiapopt




J Rheumatol. 2003 Feb;30(2):269-75.
Serum levels of pregnenolone and 17-hydroxypregnenolone in patients with rheumatoid arthritis and systemic lupus erythematosus: relation to other adrenal hormones.

Vogl D, Falk W, Dorner M, Scholmerich J, Straub RH.

Department of Internal Medicine I, Laboratory of Neuroendocrinoimmunology, University Medical Center Regensburg, Regensberg, Germany.

OBJECTIVE: In patients with rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE), low levels of adrenal steroids have been repeatedly demonstrated, but the site of alteration has not been exactly described because measurements of serum pregnenolone and 17-hydroxypregnenolone (17OHPreg) together with other adrenal steroids have never been performed. METHODS: We measured serum levels of adrenal hormones such as pregnenolone, 17OHPreg, dehydroepiandrosterone (DHEA), DHEA sulfate (DHEAS), progesterone (P), 17-hydroxyprogesterone (17OHP), androstenedione (ASD), and cortisol in 24 healthy controls, 24 patients with RA, and 24 patients with SLE. RESULTS: Serum levels of pregnenolone were similar in RA and SLE patients as compared to healthy controls irrespective of prior prednisolone therapy. In all RA and SLE patients (including those with prior prednisolone treatment), serum levels of all measured hormones except pregnenolone were significantly lower as compared to controls. In RA patients without prior prednisolone treatment, serum levels of 17OHPreg, DHEA, cortisol, and ASD were similar to controls, and serum levels of P, 17OHP, and DHEAS were significantly lower as compared to controls. In SLE patients without prior prednisolone treatment, serum levels of 17OHPreg and cortisol were similar, and serum levels of P, 17OHP, ASD, DHEA, and DHEAS were significantly lower as compared to controls. CONCLUSION: The primary hormone of the adrenal steroid cascade, pregnenolone, is almost normal in RA and SLE irrespective of corticosteroid treatment. In patients with RA, we believe that there is a near normal P