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Biology of Sex Differences Jan 2024Androgens are important sex hormones in both men and women and are supplemented when endogenous levels are low, for gender transitioning, or to increase libido....
BACKGROUND
Androgens are important sex hormones in both men and women and are supplemented when endogenous levels are low, for gender transitioning, or to increase libido. Androgens also circulate at higher levels in women with polycystic ovarian syndrome, a condition that increases the risk for cardiovascular diseases including hypertension and arterial stiffness. Since our previous work shows an important role for the G protein-coupled estrogen receptor (GPER) in arterial stiffness, we hypothesized that other hormones including androgens may impact arterial stiffness in female mice via downregulation of GPER.
METHODS
The impact of the non-aromatizable androgen dihydrotestosterone (DHT), the glucocorticoid dexamethasone, and the progestin medroxyprogesterone acetate (all 100 nM for 24 h) on GPER and ERα expression was assessed in cultured vascular smooth muscle cells using droplet digital PCR (ddPCR). To assess the in vivo impact of the DHT-induced downregulation of GPER, female ovary-intact C57Bl/6 mice at 15-16 weeks of age were treated with silastic capsules containing DHT for 4 weeks, one with a dosage expected to mimic human male DHT levels and another to double the expected human concentration (n = 8-9/group).
RESULTS
In cultured vascular smooth muscle cells, GPER mRNA was decreased by DHT (P = 0.001) but was not impacted by dexamethasone or medroxyprogesterone. In contrast, ERα expression in cultured cells was significantly suppressed by all three hormones (P < 0.0001). In control mice or mice treated with a single or double dose of DHT, a dose-dependent increase in body weight was observed (control 22 ± 2 g, single dose 24 ± 2 g, double dose 26 ± 2 g; P = 0.0002). Intracarotid stiffness measured via pulse wave velocity showed a more than two-fold increase in both DHT-treated groups (control 1.9 ± 0.3 m/s, single dose 4.3 ± 0.8 m/s, double dose 4.8 ± 1.0 m/s). This increase in arterial stiffness occurred independent of changes in blood pressure (P = 0.59). Histological analysis of aortic sections using Masson's trichrome showed a significant decrease in collagen between the control group (24 ± 5%) and the double dose group (17 ± 3%, P = 0.007), despite no changes in aortic wall thickness or smooth muscle content. Lastly, ddPCR showed that in vivo DHT treatment decreased aortic expression of both GPER (control 20 ± 5, single dose 10.5 ± 5.6, double dose 10 ± 4 copies/ng; P = 0.001) and ERα (control 54 ± 2, single dose 24 ± 13, and double dose 23 ± 12 copies/ng; P = 0.003).
CONCLUSIONS
These findings indicate that androgen promotes arterial stiffening and cardiovascular damage in female mice and is associated with decreased estrogen receptor expression. These data are important for transgender men, women using testosterone for fitness or reduced libido, as well as patients with polycystic ovarian syndrome.
Topics: Female; Humans; Male; Animals; Mice; Infant, Newborn; Dihydrotestosterone; Androgens; Estrogen Receptor alpha; Polycystic Ovary Syndrome; Pulse Wave Analysis; Estrogens; Receptors, Estrogen; Dexamethasone
PubMed: 38263051
DOI: 10.1186/s13293-024-00586-3 -
The Journal of Steroid Biochemistry and... Oct 2022Testosterone (T) and dihydrotestosterone (DHT) are the main hormones regulating reproduction and development of male animals. Although their synthesis and secretion are...
Testosterone (T) and dihydrotestosterone (DHT) are the main hormones regulating reproduction and development of male animals. Although their synthesis and secretion are regulated by the endocrine system [hypothalamic-pituitary-gonadal (adrenal) axis], it is also possible to synthesize T and DHT from the induction of two proteins: Syce1 and Syce3. As central elements of the synaptonemal complex (SC), Syce1 and Syce3 play a key role in the association of homologous chromosomes during meiosis. However, Syce1 and Syce3 also promote the synthesis of T and DHT, although potential mechanisms have yet to be revealed. In this study, Leydig and Sertoli cells, which are responsible for the production and regulation of steroid hormones in testis, were transfected with recombinant Syce1/Syce3 and silence sequence. Our results revealed the highest expression of Syce1 and Syce3 in spermatogenic cells of the testis. Moreover, overexpression or knockdown of Syce1 and Syce3 in Sertoli and Leydig cells resulted in activation or suppression of steroidogenic genes Star and Hsd3b, which are involved in a steroidogenic pathway that upregulates T synthesis. Upregulated expression of Syce1 resulted in a significant increase in Srd5a1, which can promote DHT secretion. Interestingly, Syce1 and Syce3 overexpression synergistically promoted each other's abundance. Our results define a previously unknown mechanism of Syce1 and Syce3 dependent activation of steroidogenic signaling in Sertoli and Leydig cells.
Topics: Animals; Dihydrotestosterone; Leydig Cells; Male; Mice; Sertoli Cells; Synaptonemal Complex; Testis; Testosterone; Testosterone Congeners
PubMed: 35697131
DOI: 10.1016/j.jsbmb.2022.106135 -
Biomolecules Nov 2022Androgens are steroids that modulate various processes in the body, ranging from reproduction, metabolism, and even immune response. The main androgens are testosterone,... (Review)
Review
Androgens are steroids that modulate various processes in the body, ranging from reproduction, metabolism, and even immune response. The main androgens are testosterone, dihydrotestosterone (DHT) and dehydroepiandrosterone (DHEA). These steroids modulate the development and function of immune response cells. Androgens are generally attributed to immunosuppressive effects; however, this is not always the case. Variations in the concentrations of these hormones induce differences in the innate, humoral, and cell-mediated immune response, which is concentration dependent. The androgens at the highest concentration in the organism that bind to the androgen receptor (AR) are DHEA and testosterone. Therefore, in this work, we review the effects of DHEA and testosterone on the immune response. The main findings of this review are that DHEA and testosterone induce similar but also opposite effects on the immune response. Both steroids promote the activation of regulatory T cells, which suppresses the Th17-type response. However, while testosterone suppresses the inflammatory response, DHEA promotes it, and this modulation is important for understanding the involvement of androgens in infectious (bacterial, viral and parasitic) and autoimmune diseases, as well as in the sexual dimorphism that occurs in these diseases.
Topics: Testosterone; Dehydroepiandrosterone; Androgens; Dihydrotestosterone; Adaptive Immunity
PubMed: 36551196
DOI: 10.3390/biom12121768 -
Frontiers in Endocrinology 2023Resistance exercise can significantly increase serum steroid concentrations after an exercise bout. Steroid hormones are involved in the regulation of several important...
INTRODUCTION
Resistance exercise can significantly increase serum steroid concentrations after an exercise bout. Steroid hormones are involved in the regulation of several important bodily functions (e.g., muscle growth) through both systemic delivery and local production. Thus, we aimed to determine whether resistance exercise-induced increases in serum steroid hormone concentrations are accompanied by enhanced skeletal muscle steroid concentrations, or whether muscle contractions per se induced by resistance exercise can increase intramuscular steroid concentrations.
METHODS
A counterbalanced, within-subject, crossover design was applied. Six resistance-trained men (26 ± 5 years; 79 ± 8 kg; 179 ± 10 cm) performed a single-arm lateral raise exercise (10 sets of 8 to 12 RM - 3 min rest between sets) targeting the deltoid muscle followed by either squat exercise (10 sets of 8 to 12 RM - 1 min rest) to induce a hormonal response (high hormone [HH] condition) or rest (low hormone [LH] condition). Blood samples were obtained pre-exercise and 15 min and 30 min post-exercise; muscle specimens were harvested pre-exercise and 45 min post-exercise. Immunoassays were used to measure serum and muscle steroids (total and free testosterone, dehydroepiandrosterone sulfate, dihydrotestosterone, and cortisol; free testosterone measured only in serum and dehydroepiandrosterone only in muscle) at these time points.
RESULTS
In the serum, only cortisol significantly increased after the HH protocol. There were no significant changes in muscle steroid concentrations after the protocols.
DISCUSSION
Our study provides evidence that serum steroid concentration increases (cortisol only) seem not to be aligned with muscle steroid concentrations. The lack of change in muscle steroid after protocols suggests that resistance-trained individuals were desensitized to the exercise stimuli. It is also possible that the single postexercise timepoint investigated in this study might be too early or too late to observe changes. Thus, additional timepoints should be examined to determine if RE can indeed change muscle steroid concentrations either by skeletal muscle uptake of these hormones or the intramuscular steroidogenesis process.
Topics: Humans; Male; Dihydrotestosterone; Hydrocortisone; Muscle, Skeletal; Steroids; Testosterone; Cross-Over Studies
PubMed: 37077354
DOI: 10.3389/fendo.2023.1081056 -
Asian Journal of Andrology 2018As men grow older, circulating testosterone declines while the incidence of cardiovascular disease increases. Thus, the role of sex hormones as biomarkers, and possibly... (Review)
Review
As men grow older, circulating testosterone declines while the incidence of cardiovascular disease increases. Thus, the role of sex hormones as biomarkers, and possibly contributing factors to clinical manifestations of cardiovascular disease in the increasing demographic of aging men, has attracted considerable interest. This review focuses on observational studies of endogenous androgens, namely circulating testosterone and dihydrotestosterone, which have examined their associations with cardiovascular events such as myocardial infarction and stroke. Studies which have examined the associations of endogenous estrogens, namely circulating estradiol, with these outcomes are also discussed. In large prospective cohort studies of predominantly middle-aged and older men, lower circulating testosterone consistently predicts higher incidence of cardiovascular events. Of note, both lower circulating testosterone and lower dihydrotestosterone are associated with higher incidence of stroke. These associations are less apparent when myocardial infarction is considered as the outcome. Results for estradiol are inconsistent. Lower circulating testosterone has been shown to predict higher cardiovascular disease-related mortality, as has lower circulating dihydrotestosterone. It is possible that the relationship of circulating androgens to cardiovascular events or mortality outcomes may be U-shaped rather than linear, with an optimal range defining men at lowest risk. Epidemiological studies are observational in nature and do not prove causality. Associations observed in studies of endogenous androgens need not necessarily translate into similar effects of exogenous androgens. Rigorous randomized controlled trials are needed to clarify the effects of testosterone treatment on cardiovascular risk in men.
Topics: Cardiovascular Diseases; Dihydrotestosterone; Estradiol; Humans; Incidence; Male; Mortality; Myocardial Infarction; Stroke; Testosterone
PubMed: 29199649
DOI: 10.4103/aja.aja_50_17 -
Current Molecular Pharmacology 2023Hepatocellular carcinoma (HCC) is a solid cancer with high predominance in males. Liver tissue of both genders has saturable specific oestrogen receptors. Androgen and... (Review)
Review
BACKGROUND
Hepatocellular carcinoma (HCC) is a solid cancer with high predominance in males. Liver tissue of both genders has saturable specific oestrogen receptors. Androgen and its receptor (AR) have been suggested to contribute to the predominance in men. Anti-oestrogens, like tamoxifen may reduce the expression of oestrogen receptors, sustaining cellular in HCC. In vitro and human, studies confirmed that both testosterone and dihydrotestosterone (DHT) enhanced the growth and proliferation of hepatic normal and tumour cells. Although the activity of AR is escalated by the chemical induction of hepatocarcinogenesis; clinical trials with AR-targeted agents alone failed to generate survival benefits.
PURPOSE
This review will outline the possible pathophysiological mechanisms by which both androgen and AR contribute to hepatocarcinogenesis and to which extent this pathway can be responsible for the male prevalence and if they could be pharmacological targets in HCC management.
CONCLUSION
Influencing factors that seem to be responsible for male prevalence include testosterone, dihydrotestosterone and androgen receptors, as well as, proteomic deficiency of DNA packaging, nuclear proteins and homeostasis-related functional proteins. Understanding the reasons for males, rather than females the HCC prevalence may help in suggesting new approaches by improving the anti-AR therapies through co-targeting of AR and protein kinase B (Akt)/mammalian target of rapamycin (mTOR) pathway.
Topics: Humans; Male; Female; Carcinoma, Hepatocellular; Androgens; Liver Neoplasms; Dihydrotestosterone; Prevalence; Proteomics; Receptors, Estrogen; Receptors, Androgen; Testosterone
PubMed: 36221879
DOI: 10.2174/1874467215666221010092825 -
Drug Metabolism and Disposition: the... Apr 2023Testosterone exhibits high variability in pharmacokinetics and glucuronidation after oral administration. Although testosterone metabolism has been studied for decades,...
Testosterone exhibits high variability in pharmacokinetics and glucuronidation after oral administration. Although testosterone metabolism has been studied for decades, the impact of UGT2B17 gene deletion and the role of gut bacterial -glucuronidases on its disposition are not well characterized. We first performed an exploratory study to investigate the effect of UGT2B17 gene deletion on the global liver proteome, which revealed significant increases in proteins from multiple biological pathways. The most upregulated liver proteins were aldoketoreductases [AKR1D1, AKR1C4, AKR7A3, AKR1A1, and 7-dehydrocholesterol reductase (DHCR7)] and alcohol or aldehyde dehydrogenases (ADH6, ADH1C, ALDH1A1, ALDH9A1, and ALDH5A). In vitro assays revealed that AKR1D1 and AKR1C4 inactivate testosterone to 5-dihydrotestosterone (5-DHT) and 3,5-tetrahydrotestosterone (3,5-THT), respectively. These metabolites also appeared in human hepatocytes treated with testosterone and in human serum collected after oral testosterone dosing in men. Our data also suggest that 5-DHT and 3α, 5-THT are then eliminated through glucuronidation by UGT2B7 in UGT2B17 deletion individuals. Second, we evaluated the potential reactivation of testosterone glucuronide (TG) after its secretion into the intestinal lumen. Incubation of TG with purified gut microbial -glucuronidase enzymes and with human fecal extracts confirmed testosterone reactivation into testosterone by gut bacterial enzymes. Both testosterone metabolic switching and variable testosterone activation by gut microbial enzymes are important mechanisms for explaining the disposition of orally administered testosterone and appear essential to unraveling the molecular mechanisms underlying UGT2B17-associated pathophysiological conditions. SIGNIFICANCE STATEMENT: This study investigated the association of UGT2B17 gene deletion and gut bacterial -glucuronidases with testosterone disposition in vitro. The experiments revealed upregulation of AKR1D1 and AKR1C4 in UGT2B17 deletion individuals, and the role of these enzymes to inactivate testosterone to 5-dihydrotestosterone and 3, 5-tetrahydrotestosterone, respectively. Key gut bacterial species responsible for testosterone glucuronide activation were identified. These data are important for explaining the disposition of exogenously administered testosterone and appear essential to unraveling the molecular mechanisms underlying UGT2B17-associated pathophysiological conditions.
Topics: Male; Humans; Dihydrotestosterone; Glucuronidase; Testosterone; Liver; Glucuronosyltransferase
PubMed: 36623880
DOI: 10.1124/dmd.122.000975 -
Journal of Neurotrauma Mar 2018Spinal cord injury (SCI) results in lesions that destroy tissue and disrupt spinal tracts, producing deficits in locomotor and autonomic function. We previously...
Spinal cord injury (SCI) results in lesions that destroy tissue and disrupt spinal tracts, producing deficits in locomotor and autonomic function. We previously demonstrated that motoneurons and the muscles they innervate show pronounced atrophy after SCI, and these changes are prevented by treatment with testosterone. Here, we assessed whether the testosterone active metabolites estradiol and dihydrotestosterone have similar protective effects after SCI. Young adult female rats received either sham or T9 spinal cord contusion injuries and were treated with estradiol, dihydrotestosterone, both, or nothing via Silastic capsules. Basso-Beattie-Bresnahan locomotor testing was performed weekly and voiding behavior was assessed at 3 weeks post-injury. Four weeks after SCI, lesion volume and tissue sparing, quadriceps muscle fiber cross-sectional area, and motoneuron dendritic morphology were assessed. Spontaneous locomotor behavior improved after SCI, but hormone treatments had no effect. Voiding behavior was disrupted after SCI, but was significantly improved by treatment with either estradiol or dihydrotestosterone; combined treatment was maximally effective. Treatment with estradiol reduced lesion volume, but dihydrotestosterone alone and estradiol combined with dihydrotestosterone were ineffective. SCI-induced decreases in motoneuron dendritic length were attenuated by all hormone treatments. SCI-induced reductions in muscle fiber cross-sectional areas were prevented by treatment with either dihydrotestosterone or estradiol combined with dihydrotestosterone, but estradiol treatment was ineffective. These findings suggest that deficits in micturition and regressive changes in motoneuron and muscle morphology seen after SCI are ameliorated by treatment with estradiol or dihydrotestosterone, further supporting a role for steroid hormones as neurotherapeutic agents in the injured nervous system.
Topics: Animals; Dihydrotestosterone; Estradiol; Female; Locomotion; Motor Neurons; Muscle, Skeletal; Rats; Rats, Sprague-Dawley; Recovery of Function; Spinal Cord Injuries
PubMed: 29132243
DOI: 10.1089/neu.2017.5329 -
FEBS Letters Mar 2022The mechanisms through which the androgen-dependent activation of the androgen receptor (AR) regulates gravid uterine ferroptosis remain unknown. We show that while...
The mechanisms through which the androgen-dependent activation of the androgen receptor (AR) regulates gravid uterine ferroptosis remain unknown. We show that while co-exposure of pregnant rats to the androgen 5α-dihydrotestosterone (DHT) and insulin (INS) triggered uterine ferroptotic signaling cascades, additional treatment with the anti-androgen flutamide increased expression of the key ferroptosis-inhibitory proteins SLC7A11, GSH, and GPX4; reduced iron content; normalized levels of ferroptosis-associated Tfrc, Fpn1, and Ho1 mRNAs; reduced levels of proteins modified by 4-HNE (a marker of ferroptosis); and restored protein levels of NRF2, a key transcription factor regulating antioxidant defense signaling, in the gravid uterus. Furthermore, exposure to DHT alone increased uterine ferroptosis, and NRF2 abundance was negatively correlated with AR status. Co-immunoprecipitation and Western blot assays revealed that the AR physically interacted with endogenous NRF2, and this interaction was increased by DHT exposure in vivo. Our results suggest that AR overactivation and NRF2 suppression cooperate in the regulation of NRF2-targets in uterine ferroptosis.
Topics: Androgens; Animals; Dihydrotestosterone; Female; Ferroptosis; NF-E2-Related Factor 2; Pregnancy; Rats; Receptors, Androgen; Signal Transduction; Uterus
PubMed: 35038776
DOI: 10.1002/1873-3468.14289 -
Brain and Behavior Nov 2020Testosterone has been postulated to be involved in ALS causation.
OBJECTIVE
Testosterone has been postulated to be involved in ALS causation.
MATERIALS AND METHODS
CSF levels of free testosterone and dihydrotestosterone were measured in 13 ALS patients [7 males, 6 females] and 22 controls [12 males, 10 females].
RESULTS
CSF free testosterone levels did not show any significant differences but CSF dihydrotestosterone levels were significantly decreased in all male and female ALS patients.
CONCLUSIONS
DHT is probably integral to survival of motor neurons. In patients predisposed to develop ALS, there is possibly a sort of "testosterone resistance" at level of blood-brain barrier [BBB] existing right from birth and is likely the result of dysfunctional transport protein involved in testosterone transfer across the BBB. In these patients, lesser amount of testosterone is able to breach the BBB and enter the central neural axis. Lesser amount of testosterone is available to 5 α reductase in the anterior pituitary to be converted to DHT and lesser amount of DHT is generated. There is inadequate negative feedback suppression of LH at the level of anterior pituitary by DHT. As a result of higher LH levels, testosterone levels rise in the peripheral testosterone fraction [the fraction outside the BBB] and this explains the various physical attributes of ALS patients like lower Ratio of the index and ring finger lengths (2D:4D ratio), increased incidence of early onset alopecia etc. This deficiency of DHT leads to motor neuron death causing ALS.
Topics: Amyotrophic Lateral Sclerosis; Dihydrotestosterone; Female; Fingers; Humans; Male; Motor Neurons; Testosterone
PubMed: 33047895
DOI: 10.1002/brb3.1645