Kegg Pathway: Androgen and estrogen metabolism

Endocr Relat Cancer. 2009 Sep 23;
Ferlin A, Ganz F, Pengo M, Selice R, Frigo AC, Foresta C

It is generally assumed that the development of testicular germ cell tumour (TGCT) is under endocrine control. In particular, an unbalanced Androgen/estrogen levels and/or activity is believed to represent key events for TGCT development and progression. Furthermore, recent evidence suggested a strong genetic component for TGCT. In this study we analysed whether genetic variation in estrogen receptor genes and steroid hormone metabolism genes are associated with TGCT. We genotyped for 17 polymorphic markers in 11 genes 234 TGCT cases and 218 controls: estrogen receptor (ESR1, ESR2), CYP19A1 (aromatase), HSD17B1 and HSD17B4 dehydrogenases that convert potent Androgens and estrogens to weak hormones, cytochrome P450 hydroxylating enzymes CYP1A1, CYP1A2, and CYP1B1, and the metabolic enzymes COMT, SULT1A1 and SULT1E1. We observed significant association of rs11205 in HSD17B4 with TGCT. TGCT risk was increased twofold per copy of the minor A allele at this locus (OR = 2.273, 95% CI = 1.737-2.973). Homozygous carriage of the minor A allele was associated with an over fourfold increased risk of TGCT (OR = 4.561, 95% CI = 2.615-7.955) compared with homozygous carriage of the major G allele. The risk was increased both for seminoma (OR = 5.327, 95% CI = 2.857-9.931) and for non seminoma (OR = 3.222, 95% CI = 1.471-7.059). We found for the first time association of polymorphisms in HSD17B4 gene with TGCT. Our findings expand current knowledge on the role of genetic contribution to testicular cancer susceptibility and support the hypothesis that variations in hormone metabolism genes might change the hormonal environment implicated in testicular carcinogenesis.

Mol Cell Endocrinol. 2010 Jan 15; 314(1): 31-40
Lemcke S, Hönnscheidt C, Waschatko G, Bopp A, Lütjohann D, Bertram N, Gehrig-Burger K

The Androgen dehydroepiandrosterone (DHEA) has been reported to protect neuronal cells against dysfunction and apoptosis. Several signaling pathways involved in these effects have been described but little is known about the intracellular trafficking of DHEA. We describe design, synthesis and characterization of DHEA-Bodipy, a novel fluorescent DHEA analog. DHEA-Bodipy proved to be a functional DHEA derivative: DHEA-Bodipy (i) induced estrogen receptor alpha-mediated gene activation, (ii) protected PC12 rat pheochromocytoma cells against serum-deprivation-induced apoptosis, and (iii) induced stress fibers and focal adhesion contacts in SH-SY5Y human neuroblastoma cells. DHEA-Bodipy bound rapidly and specifically to plasma membranes of living PC12 cells. We analyzed metabolism and trafficking of DHEA-Bodipy in human neuroblastoma cells. DHEA-Bodipy is the first functional fluorescent DHEA derivative suitable for live cell imaging of intracellular DHEA transport and localization.

Reprod Domest Anim. 2009 Jul; 44 Suppl 2: 3-15
Concannon PW

In dogs, the termination of the 3-10-month obligate anoestrus involves selection of a cohort of LH-sensitive follicles, presumably from a wave of dominant small antral follicles that would otherwise undergo atresia. The number and size of such follicles appears to increase, especially during the last 50 days of anoestrus when the already elevated concentrations of FSH become further elevated. The final selection and eventual terminal development of these follicles is caused by an increased frequency of high-amplitude LH pulses at the end of anoestrus. Concomitant increases in FSH are typically small or negligible. High concentrations of FSH in anoestrus are likely to be important in maintaining, if not stimulating, overlapping waves of dominant follicles throughout anoestrus, their expression of aromatase activity and basal oestradiol secretion sufficient to suppress LH by negative feedback. An attractive hypothesis is that late anoestrus increases in LH-stimulate synthesis of precursor Androgen for already available FSH-dependent aromatase. After 7 or more days of elevated LH, and perhaps 2-5 days of semi-autonomous growth, with maximal oestradiol production reached, follicle capacity to further increase oestradiol becomes limited and excess progesterone becomes increasingly secreted. The pre-ovulatory LH surge and oestrus onset are then triggered - often synchronously and in concert with the terminal maturation of the follicles - by central effects of the large decrease in the oestrogen to progestin ratio. Follicular endocrine and paracrine events during and following the LH surge are likely similar to those reported for other species. The prolonged luteal phase lengths of 55-75 days in non-pregnant bitches bracket the 64 +/- 1 day in pregnancy and represent a genetically programmed luteal cell lifespan approximating gestation length as occurs in the luteal phase of hysterectomized animals of most polyoestrous artiodactyls and rodents. The 30-40-day slow regression after day 20 to 30 involves periodic cell death, diminution in cell size, low levels of apoptosis and minimal or modest involvement of endogenous prostaglandin F (PGF) production. The canine corpus luteum (CL) is dependent on both LH and prolactin as stimulating luteotrophins by day 15, and as required luteotrophins by days 20-25, if not earlier. Thereafter, both luteotrophins likely have cellular mechanisms of action similar to those reported for other species. Progesterone secretion during pregnancy is greatly enhanced by characteristic, and probably relaxin-stimulated, increases in prolactin concentration starting at or after day 25, and persisting to term. Near term, foetoplacental maturation results in the placental release of large, luteolytic amounts of PGF for 1-2 days pre-partum. Pre-partum luteolysis, like that induced by exogenous prostaglandin, likely involves a cascade enhanced by the removal of progesterone inhibition of PGF release and some degree of intra-luteal PGF synthesis. That a likely twofold or greater increase in progesterone production by the CL of pregnancy does not result in significantly higher serum progesterone than in non-pregnant metoestrus relates to several biological changes, including a large increase in plasma volume of distribution, increased metabolism of progesterone by increased uterine, placental and mammary masses and increased liver clearance and excretion of progesterone and progesterone metabolite. Anoestrus length and ovarian cycle intervals, variable within and among bitches, are likely affected by neuroendocrine components of an endogenous circannual cycle, albeit only photo-entrained in the Basenji breed. This may be modified by the prior luteal phase, exposure to oestrus female pheromones and as yet unknown mechanisms that likely operate via inhibitory opioidergic and/or stimulatory dopaminergic hypothalamic pathways affecting late anoestrus increases in LH.

Circulation. 2009 Sep 29; 120(13): 1231-40
Bonnet S, Paulin R, Sutendra G, Dromparis P, Roy M, Watson KO, Nagendran J, Haromy A, Dyck JR, Michelakis ED

BACKGROUND: The remodeled vessel wall in many vascular diseases such as restenosis after injury is characterized by proliferative and apoptosis-resistant vascular smooth muscle cells. There is evidence that proproliferative and antiapoptotic states are characterized by a metabolic (glycolytic phenotype and hyperpolarized mitochondria) and electric (downregulation and inhibition of plasmalemmal K(+) channels) remodeling that involves activation of the Akt pathway. Dehydroepiandrosterone (DHEA) is a naturally occurring and clinically used steroid known to inhibit the Akt axis in cancer. We hypothesized that DHEA will prevent and reverse the remodeling that follows vascular injury. METHODS AND RESULTS: We used cultured human carotid vascular smooth muscle cell and saphenous vein grafts in tissue culture, stimulated by platelet-derived growth factor to induce proliferation in vitro and the rat carotid injury model in vivo. DHEA decreased proliferation and increased vascular smooth muscle cell apoptosis in vitro and in vivo, reducing vascular remodeling while sparing healthy tissues after oral intake. Using pharmacological (agonists and antagonists of Akt and its downstream target glycogen-synthase-kinase-3beta [GSK-3beta]) and molecular (forced expression of constitutively active Akt1) approaches, we showed that the effects of DHEA were mediated by inhibition of Akt and subsequent activation of GSK-3beta, leading to mitochondrial depolarization, increased reactive oxygen species, activation of redox-sensitive plasmalemmal voltage-gated K(+) channels, and decreased [Ca(2+)](i). These functional changes were accompanied by sustained molecular effects toward the same direction; by decreasing [Ca(2+)](i) and inhibiting GSK-3beta, DHEA inhibited the nuclear factor of activated T cells transcription factor, thus increasing expression of Kv channels (Kv1.5) and contributing to sustained mitochondrial depolarization. These results were independent of any steroid-related effects because they were not altered by Androgen and estrogen inhibitors but involved a membrane G protein-coupled receptor. CONCLUSIONS: We suggest that the orally available DHEA might be an attractive candidate for the treatment of systemic vascular remodeling, including restenosis, and we propose a novel mechanism of action for this important hormone and drug.

Environ Health Perspect. 2009 Sep; 117(9): 1454-60
Goncharov A, Rej R, Negoita S, Schymura M, Santiago-Rivera A, Morse G, , Carpenter DO

BACKGROUND: Polychlorinated biphenyls (PCBs) and chlorinated pesticides are endocrine disruptors, altering both thyroid and estrogen hormonal systems. Less is known of action on Androgenic systems. OBJECTIVE: We studied the relationship between serum concentrations of testosterone in relation to levels of PCBs and three chlorinated pesticides in an adult Native American (Mohawk) population. METHODS: We collected fasting serum samples from 703 adult Mohawks (257 men and 436 women) and analyzed samples for 101 PCB congeners, hexachlorobenzene (HCB), dichlorodiphenyldichloroethylene (DDE), and mirex, as well as testosterone, cholesterol, and triglycerides. The associations between testosterone and tertiles of serum organochlorine levels (both wet weight and lipid adjusted) were assessed using a logistic regression model while controlling for age, body mass index (BMI), and other analytes, with the lowest tertile being considered the referent. Males and females were considered separately. RESULTS: Testosterone concentrations in males were inversely correlated with total PCB concentration, whether using wet-weight or lipid-adjusted values. The odds ratio (OR) of having a testosterone concentration above the median was 0.17 [95% confidence interval (CI), 0.05-0.69] for total wet-weight PCBs (highest vs. lowest tertile) after adjustment for age, BMI, total serum lipids, and three pesticides. The OR for lipid-adjusted total PCB concentration was 0.23 (95% CI, 0.06-0.78) after adjustment for other analytes. Testosterone levels were significantly and inversely related to concentrations of PCBs 74, 99, 153, and 206, but not PCBs 52, 105, 118, 138, 170, 180, 201, or 203. Testosterone concentrations in females are much lower than in males, and not significantly related to serum PCBs. HCB, DDE, and mirex were not associated with testosterone concentration in either men or women. CONCLUSIONS: Elevation in serum PCB levels is associated with a lower concentration of serum testosterone in Native American men.

J Cell Physiol. 2009 Dec; 221(3): 771-7
Rossi V, Staibano S, Abbondanza C, Pasquali D, De Rosa C, Mascolo M, Bellastella G, Visconti D, De Bellis A, Moncharmont B, De Rosa G, Puca GA, Bellastella A, Sinisi AA

The nuclear protein methyl-transferase Retinoblastoma-interacting zinc-finger protein 1 (RIZ1) is considered to be a downstream effector of estrogen action in target tissues. Silencing of RIZ1 expression is common in many tumors. We analyzed RIZ1 expression in normal and malignant prostate tissue and evaluated whether estradiol (E2) or dihydrotestosterone (DHT) treatment modulated RIZ1 in cultured prostate epithelial cells (PEC). Moreover, we studied the possible involvement of RIZ1 in estrogen action on the EPN prostate cell line, constitutively expressing both estrogen receptor (ER)-alpha and beta. RIZ1 protein, found in the nucleus of normal PECs by immunohistochemistry, was progressively lost in cancer tissues as the Gleason score increased and was only detected in the cytoplasmic compartment. RIZ1 transcript levels, as assayed by semi-quantitative RT-PCR in primary PEC cultures, were significantly reduced in cancer cells (P < 0.05). In EPN DHT treatment significantly increased RIZ1 transcript and protein levels (P < 0.05); E2 induced a reduction of S phase without significant changes of RIZ1 expression. In E2-treated EPN cell extracts RIZ co-immunoprecipitated with ERbeta and ERalpha. Our data demonstrate that RIZ1 is expressed in normal PECs and down-regulated in cancer cells, with a switch of its sub-cellular localization from the nucleus to the cytoplasm upon cancer grade progression. RIZ1 expression levels in the PECs were modulated by DHT or E2 treatment in vitro. Furthermore, the E2 effects on ER-expressing prostate cells involve RIZ1, which confirms a possible role for ER-mediated pathways in a non-classic E(2)-target tissue.

Cancer Res. 2009 Sep 15; 69(18): 7270-7
Genua M, Pandini G, Sisci D, Castoria G, Maggiolini M, Vigneri R, Belfiore A

Insulin-like growth factor-I receptor (IGF-IR) overexpression may play a role in prostate cancer progression. We found previously that, in prostate cancer cells, IGF-IR is up-regulated by both Androgens and estrogens via a nongenotropic pathway. We now show that, in prostate cancer cells, stimulation with either Androgens or estrogens up-regulates IGF-IR by inducing cyclic AMP response element-binding protein (CREB) activation. Both sex steroids phosphorylated CREB at Ser(133) in a dose-dependent manner in Androgen receptor (AR)-positive LNCaP cells, whereas only estrogens phosphorylated CREB in AR-negative PC3 cells. CREB phosphorylation involved c-Src-dependent extracellular signal-regulated kinase 1/2 activation, but not protein kinase A, protein kinase C, or calmodulin-dependent kinase II, and occurred also in cells transfected with AR or estrogen receptor mutants that do not localize into the nucleus. CREB silencing abrogated IGF-IR up-regulation and promoter activation. We also showed that CREB binds to IGF-IR promoter region and identified the relevant CREB-binding site at the 5'-untranslated region fragment of IGF-IR promoter. In conclusion, we describe a novel mechanism of IGF-IR up-regulation and promoter activity by CREB activation, induced by sex steroids, through a nongenotropic signaling.

J Clin Endocrinol Metab. 2009 Oct; 94(10): 3806-15
Cawthon PM, Ensrud KE, Laughlin GA, Cauley JA, Dam TT, Barrett-Connor E, Fink HA, Hoffman AR, Lau E, Lane NE, Stefanick ML, Cummings SR, Orwoll ES,

CONTEXT: As men age, the prevalence of frailty increases whereas levels of Androgens decline. Little is known about the relation between these factors. OBJECTIVE: The aim of this study was to assess cross-sectional and longitudinal associations of estradiol, bioavailable estradiol, testosterone, bioavailable testosterone (bioT), and SHBG with frailty status. DESIGN AND SETTING: The Osteoporotic Fractures in Men (MrOS) study was conducted at six U.S. clinical centers. PARTICIPANTS: A total of 1469 community-dwelling men at least 65 yr old with baseline data participated; 1245 men had frailty status reassessed 4.1 yr later. MAIN OUTCOME MEASURE: Proportional odds models estimated the likelihood of greater frailty status. Frail men had at least three of the following: weakness, slowness, low activity, exhaustion, and shrinking/sarcopenia; intermediate men had one or two criteria; and robust men had none. At follow-up, death was included as an additional ordinal outcome. Sex hormones were assayed by spectrometry/chromatographic methods. RESULTS: In cross-sectional analyses, men in the lowest quartile of bioT had 1.39-fold (95% confidence interval, 1.02, 1.91) increased odds of greater frailty status compared to men in the highest quartile after adjustment for covariates including age, body size, health status, and medical conditions. In age-adjusted longitudinal analyses, men in the lowest quartile of bioT had 1.51-fold (95% confidence interval, 1.10, 2.07) increased odds of greater frailty status 4.1 yr later. This association was largely attenuated by adjustment for covariates. No other hormones were associated in a cross-sectional or longitudinal manner with frailty status after adjustment. CONCLUSIONS: Low levels of bioT were independently associated with worse baseline frailty status. Frailty status should be considered as an outcome in trials of testosterone supplementation.

Reprod Biol. 2009 Jul; 9(2): 161-79
Wasowska B, Stefańczyk-Krzymowska S

The present study was undertaken to elucidate whether an increased, but physiological, amount of progesterone (P(4)) supplied to the porcine corpus luteum (CL) affects luteal secretion of Androgens and estrogens in freely moving gilts. On day 9 of the estrous cycle, the jugular veins as well as both ovarian arteries and both ovarian veins of gilts were cannulated. Progesterone was infused into the right ovarian arteries of experimental gilts (n=5) on days 10, 11 and 12 of the estrous cycle at a rate adequate to physiological retrograde transfer found during the middle luteal phase of the cycle. The left ovarian arteries of the experimental gilts were infused with saline. Both ovarian arteries of the control gilts (n=5) were infused with saline. The P(4) infusion rate was 0.62 microg/min (10 day), 2x0.62 microg/min (11 day) and 3x0.62 microg/min (12 day). Blood samples were collected from the jugular vein and both ovarian veins of the experimental and control gilts on days 10-12 of the estrous cycle before and after P(4) or saline infusion. The mean plasma androstenedione (A(4)) level in the ovarian vein ipsilateral to the P(4)-infused ovary was higher (p<0.01) on days 10-12 of the estrous cycle than those found in the contralateral ovarian vein of the experimental gilts as well as the control gilts. The ovarian venous level of testosterone (T) in the ovarian vein ipsilateral to the P(4)-infused ovary on days 10-12 of the estrous cycle was not significantly different (p>0.05) from those found in the contralateral ovarian vein of the experimental gilts and ovarian vein of the control gilts. However, on day 12, a decrease in T concentration was demonstrated in the ovarian vein ipsilateral to the P4-infused ovary in comparison to those of the contralateral and control ovarian veins. The mean plasma 17beta-estradiol (E(2)) level in the ovarian vein ipsilateral to the P(4)-infused ovary was lower on days 10-12 than those found in the contralateral ovarian vein of the experimental gilts and in the ovarian vein of the control gilts (p<0.001). The results of the present paper indicate that local elevation of P4 concentration in blood supplying the ovary during the middle luteal phase of the porcine estrous cycle affected local secretion of Androgens and estrogens. The effect of P(4) on the secretion of Androgens and estrogens suggested the existence of a short regulatory loop of a positive feedback for A(4) secretion and a negative feedback for E(2) secretion.

J Dent Res. 2009 Aug; 88(8): 704-8
Orwoll ES, Chan BK, Lambert LC, Marshall LM, Lewis C, Phipps KR

Sex steroids have a significant effect on skeletal biology in men, with reduced levels being associated with lower skeletal bone mass and cortical thickness. The purpose of this study was to determine if sex steroids are associated with periodontitis and tooth loss in a cohort of 1210 older dentate men followed for 3 years. Periodontal measures included attachment loss, pocket depth, gingival bleeding, and number of teeth. Baseline serum testosterone and estradiol were measured by radioimmunoassay. Severe periodontitis was common at baseline (38%), and progression occurred in 32% of the cohort. Incident tooth loss occurred in 22% of the cohort. Testosterone, estradiol, and sex hormone binding globulin (SHBG) concentrations were not related to baseline periodontal status or number of teeth. Moreover, there was no relationship between sex steroid levels and periodontitis progression or incident tooth loss. Although periodontitis, progression of periodontitis, and tooth loss are common in older men, they were not associated with sex steroids.

Biochim Biophys Acta. 2009 Dec; 1791(12): 1206-15
Pettersson H, Lundqvist J, Oliw E, Norlin M

The current study presents data indicating that 5alpha-androstane-3alpha,17beta-diol (3alpha-Adiol) undergoes a previously unknown metabolism into hydroxymetabolites, catalyzed by CYP7B1. 3alpha-Adiol is an Androgenic steroid which serves as a source for the potent Androgen dihydrotestosterone and also can modulate gamma-amino butyric acid A (GABA(A)) receptor function in the brain. The steroid hydroxylase CYP7B1 is known to metabolize cholesterol derivatives, sex hormone precursors and certain estrogens, but has previously not been thought to act on Androgens or 3alpha-hydroxylated steroids. 3alpha-Adiol was found to undergo NADPH-dependent metabolism into 6- and 7-hydroxymetabolites in incubations with porcine microsomes and human kidney-derived HEK293 cells, which are high in CYP7B1 content. This metabolism was suppressed by addition of steroids known to be metabolized by CYP7B1. In addition, 3alpha-Adiol significantly suppressed CYP7B1-mediated catalytic reactions, in a way as would be expected for substrates that compete for the same enzyme. Recombinant expression of human CYP7B1 in HEK293 cells significantly increased the rate of 3alpha-Adiol hydroxylation. Furthermore, the observed hydroxylase activity towards 3alpha-Adiol was very low or undetectable in livers of Cyp7b1(-/-) knockout mice. The present results indicate that CYP7B1-mediated catalysis may play a role for control of the cellular levels of Androgens, not only of estrogens. These findings suggest a previously unknown mechanism for metabolic elimination of 3alpha-Adiol which may impact intracellular levels of dihydrotestosterone and GABA(A)-modulating steroids.