Browsing by Subject "Testosterone"
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Item Effect of Transdermal Testosterone and Oral Progesterone on Drug-Induced QT Interval Lengthening in Older Men(American Heart Association, 2019-09-23) Muensterman, Elena Tomaselli; Jaynes, Heather A.; Sowinski, Kevin M.; Overholser, Brian R.; Shen, Changyu; Kovacs, Richard J.; Tisdale, James E.; Medicine, School of MedicineItem Hormonal suppression of mini-puberty in a neonate with mosaic 45X/46XY disorder of sexual development(Elsevier, 2020-05-03) Kaefer, Martin; Eugster, Erica; Medicine, School of MedicineDisorders of Sex Development (DSD) are some of the most controversial and challenging conditions that pediatric urologists treat. This may be especially true in mosaic 45X/46XY DSD, due to the inability to ascertain in the neonatal period which gender identity will best suit a given child with this condition. It has therefore been proposed to forgo any irreversible surgical interventions. In order to address the concern of early testosterone production in a nonsurgical manner we describe a case in which we treat a patient with a GnRH agonist to block the early physiologic rise in testosterone during the neonatal mini-puberty.Item Host Factors That Influence Coxsackievirus B3 Replication and Pathogenensis(2023-04) Dhalech, Adeeba Haroon; Robinson, Christopher M.; Hurley, Thomas D.; Katzenellenbogen, Rachel A.; Richer, Martin J.; Spinola, Stanley M.Enteric viruses are infectious human pathogens that initiate infection in the gastrointestinal tract. They follow a fecal-oral route of transmission and are spread by contamination of food, water, or contact between individuals. Furthermore, enteric viruses also cause significant morbidity, mortality, and economic burdens yearly. Coxsackievirus (CV) is commonly isolated among enteric viruses and is an etiological agent of hand, foot, and mouth disease, hemorrhagic conjunctivitis, and myocarditis. The virus predominantly infects infants and young children and accounts for 11% of the fatality rate in neonates. Despite CV’s impact on human health, there are no treatments or vaccines for CV infections. Using a mouse model to study a key CV, Coxsackievirus B3 (CVB3), our laboratory has found two critical factors that impact CVB3 replication and pathogenesis. First, we have demonstrated that intestinal bacteria enhance intestinal CVB3 replication. We found that certain specific bacteria (Salmonella enterica) and its cell wall components, like lipopolysaccharides (LPS), enhanced CVB3 stability and infectivity in vitro. Additionally, we found that particular constituents of LPS are required for stability to occur. These data suggest that specific bacteria may be integral in maintaining CVB3 infectivity in the intestine. Besides virus-microbiome interaction, CVB3 is also impacted by sex hormones. Using castrated mice models, we observed a sex bias to CVB3 infection, with male mice succumbing to CVB3-induced disease at an increased rate compared to female mice. Our data suggest that testosterone, a predominant male sex hormone, enhanced CVB3 intestinal replication and viral dissemination to organs in male and female mice, but lethality only in male mice. Moreover, testosterone also affected the immune response by reducing the activation of the CD8+ T cells. CD8+ T cells are required to clear the viral infection and are integral in vaccine development. In contrast, we found an enhanced CD8+ T cell response in female mice to CVB3 infection, suggesting a sex-dependent T cell response that may underlie the sex bias in disease. Overall, these data represent an essential advancement in the CV field and will help develop future therapeutics and aid in vaccine design to limit CV infections.Item Interrelationship Between Alcohol Intake and Endogenous Sex-Steroid Hormones on Diabetes Risk in Postmenopausal Women(Informa UK (Taylor & Francis), 2015) Rohwer, Rachelle D.; Liu, Simin; You, Nai-Chieh; Buring, Julie E.; Manson, JoAnn E.; Song, Yiqing; Department of Epidemiology, Richard M. Fairbanks School of Public HealthOBJECTIVE: We examined whether circulating concentrations of sex hormones, including estradiol, testosterone, sex hormone-binding globulin (SHBG), and dehydroepiandrosterone sulfate (DHEAS), were associated with alcohol intake or mediated the alcohol-type 2 diabetes (T2D) association. METHODS: Among women not using hormone replacement therapy and free of baseline cardiovascular disease, cancer, and diabetes in the Women's Health Study, 359 incident cases of T2D and 359 matched controls were chosen during 10 years of follow-up. RESULTS: Frequent alcohol intake (≥1 drink/day) was positively and significantly associated with higher plasma estradiol concentrations in an age-adjusted model (β = 0.14, 95% confidence interval [CI], 0.03, 0.26), compared to rarely/never alcohol intake. After adjusting for additional known covariates, this alcohol-estradiol association remained significant (β = 0.19, 95% CI, 0.07, 0.30). Testosterone (β = 0.13, 95% CI, -0.05, 0.31), SHBG (β = 0.07, 95% CI, -0.07, 0.20), and DHEAS (β = 0.14, 95% CI, -0.04, 0.31) showed positive associations without statistical significance. Estradiol alone or in combination with SHBG appeared to influence the observed protective association between frequent alcohol consumption and T2D risk, with a 12%-21% reduction in odds ratio in the multivariate-adjusted models. CONCLUSIONS: Our cross-sectional analysis showed positive associations between alcohol intake and endogenous estradiol concentrations. Our prospective data suggested that baseline concentrations of estradiol, with or without SHBG, might influence the alcohol-T2D association in postmenopausal women.Item Natural Selection on Testosterone Production in a Wild Songbird Population(The American Naturalist, 2010-04-15) McGlothlin, Joel W.; Whittaker, Danielle J.; Schrock, Sara E.; Gerlach, Nicole M.; Jawor, Jodie M.; Snajdr, Eric; Ketterson, Ellen D.Because of their role in mediating life‐history trade‐offs, hormones are expected to be strongly associated with components of fitness; however, few studies have examined how natural selection acts on hormonal variation in the wild. In a songbird, the dark‐eyed junco (Junco hyemalis), field experiments have shown that exogenous testosterone alters individuals’ resolution of the survival‐reproduction trade‐off, enhancing reproduction at the expense of survival. Here we used standardized injections of gonadotropin‐releasing hormone (GnRH) to assay variation in the testosterone production of males. Using measurements of annual survival and reproduction, we found evidence of strong natural selection acting on GnRH‐induced increases in testosterone. Opposite to what would be predicted from the survival‐reproduction trade‐off, patterns of selection via survival and reproduction were remarkably similar. Males with GnRH‐induced testosterone production levels that were slightly above the population mean were more likely to survive and also produced more offspring, leading to strong stabilizing selection. Partitioning reproduction into separate components revealed positive directional selection via within‐pair siring success and stabilizing selection via extrapair mating success. Our data represent the most complete demonstration of natural selection on hormones via multiple fitness components, and they complement previous experiments to illuminate testosterone’s role in the evolution of life‐history trade‐offs.Item Protective effects of gonadal hormones on spinal motoneurons following spinal cord injury(Medknow Publications, 2018-06) Sengelaub, Dale R.; Xu, Xiao-Ming; Neurological Surgery, School of MedicineSpinal cord injury (SCI) results in lesions that destroy tissue and disrupt spinal tracts, producing deficits in locomotor and autonomic function. The majority of treatment strategies after SCI have concentrated on the damaged spinal cord, for example working to reduce lesion size or spread, or encouraging regrowth of severed descending axonal projections through the lesion, hoping to re-establish synaptic connectivity with caudal targets. In our work, we have focused on a novel target for treatment after SCI, surviving spinal motoneurons and their target musculature, with the hope of developing effective treatments to preserve or restore lost function following SCI. We previously demonstrated that motoneurons, and the muscles they innervate, show pronounced atrophy after SCI. Importantly, SCI-induced atrophy of motoneuron dendrites can be attenuated by treatment with gonadal hormones, testosterone and its active metabolites, estradiol and dihydrotestosterone. Similarly, SCI-induced reductions in muscle fiber cross-sectional areas can be prevented by treatment with androgens. Together, these findings suggest that regressive changes in motoneuron and muscle morphology seen after SCI can be ameliorated by treatment with gonadal hormones, further supporting a role for steroid hormones as neurotherapeutic agents in the injured nervous system.Item Recruiting transgender men in the Southeastern United States for genital microbiome research: Lessons learned(Public Library of Science, 2024-08-12) Van Gerwen, Olivia T.; Sherman, Z. Alex; Kay, Emma Sophia; Wall, Jay; Lewis, Joy; Eastlund, Isaac; Graves, Keonte J.; Richter, Saralyn; Pontius, Angela; Aaron, Kristal J.; Siwakoti, Krishmita; Rogers, Ben; Toh, Evelyn; Elnaggar, Jacob H.; Taylor, Christopher M.; Van Wagoner, Nicholas J.; Muzny, Christina A.; Microbiology and Immunology, School of MedicineBackground: Transgender men (TGM) are underrepresented in genital microbiome research. Our prospective study in Birmingham, AL investigated genital microbiota changes over time in TGM initiating testosterone, including the development of incident bacterial vaginosis (iBV). Here, we present lessons learned from recruitment challenges encountered during the conduct of this study. Methods: Inclusion criteria were assigned female sex at birth, TGM or non-binary identity, age ≥18 years, interested in injectable testosterone but willing to wait 7 days after enrollment before starting, and engaged with a testosterone-prescribing provider. Exclusion criteria were recent antibiotic use, HIV/STI infection, current vaginal infection, pregnancy, or past 6 months testosterone use. Recruitment initiatives included community advertisements via flyers, social media posts, and referrals from local gender health clinics. Results: Between February 2022 and October 2023, 61 individuals contacted the study, 17 (27.9%) completed an in-person screening visit, and 10 (58.8%) of those screened were enrolled. The primary reasons for individuals failing study screening were having limited access to testosterone-prescribing providers, already being on testosterone, being unwilling to wait 7 days to initiate testosterone therapy, or desiring the use of topical testosterone. Engagement of non-White TGM was also minimal. Conclusion: Despite robust study inquiry by TGM, screening and enrollment challenges were faced including engagement by TGM not yet in care and specific study eligibility criteria. Excitement among TGM for research representation should be leveraged in future work by engaging transgender community stakeholders at the inception of study development, particularly regarding feasibility of study inclusion and exclusion criteria, as well as recruitment of TGM of color. These results also highlight the need for more clinical resources for prescribing gender-affirming hormone therapy, especially in the Southeastern US.Item Stop calling it a choice: Biological factors drive homosexuality(The Conversation US, Inc., 2019-09-03) Sullivan, BillItem Targeted activation of androgen receptor signaling in the periosteum improves bone fracture repair(Springer Nature, 2022-02-08) Lan, Kuo-Chung; Wei, Kuo-Ting; Lin, Pei-Wen; Lin, Ching-Chen; Won, Pei-Ling; Liu, Ya-Fen; Chen, Yun-Ju; Cheng, Bi-Hua; Chu, Tien-Min G.; Chen, Jia-Feng; Huang, Ko-En; Chang, Chawnshang; Kang, Hong-Yo; Biomedical and Applied Sciences, School of DentistryLow testosterone level is an independent predictor of osteoporotic fracture in elderly men as well as increased fracture risk in men undergoing androgen deprivation. Androgens and androgen receptor (AR) actions are essential for bone development and homeostasis but their linkage to fracture repair remains unclear. Here we found that AR is highly expressed in the periosteum cells and is co-localized with a mesenchymal progenitor cell marker, paired-related homeobox protein 1 (Prrx1), during bone fracture repair. Mice lacking the AR gene in the periosteum expressing Prrx1-cre (AR-/Y;Prrx1::Cre) but not in the chondrocytes (AR-/Y;Col-2::Cre) exhibits reduced callus size and new bone volume. Gene expression data analysis revealed that the expression of several collagens, integrins and cell adhesion molecules were downregulated in periosteum-derived progenitor cells (PDCs) from AR-/Y;Prrx1::Cre mice. Mechanistically, androgens-AR signaling activates the AR/ARA55/FAK complex and induces the collagen-integrin α2β1 gene expression that is required for promoting the AR-mediated PDCs migration. Using mouse cortical-defect and femoral graft transplantation models, we proved that elimination of AR in periosteum of host mice impairs fracture healing, regardless of AR existence of transplanted donor graft. While testosterone implanted scaffolds failed to complete callus bridging across the fracture gap in AR-/Y;Prrx1::Cre mice, cell-based transplantation using DPCs re-expressing AR could lead to rescue bone repair. In conclusion, targeting androgen/AR axis in the periosteum may provide a novel therapy approach to improve fracture healing.Item Testosterone does not shorten action potential duration in Langendorff perfused rabbit ventricles(Elsevier, 2023-10) Ueoka, Akira; Sung, Yen-Ling; Liu, Xiao; Rosenberg, Carine; Chen, Zhenhui; Everett, Thomas H, IV; Rubart, Michael; Tisdale, James E.; Chen, Peng-Sheng; Pediatrics, School of MedicineBackground: Women have longer baseline QT intervals than men. Because previous studies showed that testosterone and 5α-dihydrotestosterone shorten the ventricular action potential duration (APD) in animal models, differential testosterone concentrations may account for the sex differences in QT interval. Objective: The purpose of this study was to test the hypothesis that testosterone shortens the APD in Langendorff-perfused rabbit ventricles. Methods: We performed optical mapping studies in hearts with or without testosterone administration. Acute studies included 26 hearts using 2 different protocols, including 17 without and 9 with atrioventricular (AV) block. For chronic studies, we implanted testosterone pellets subcutaneously in 7 female rabbits for 2-3 weeks before optical mapping studies during complete AV block. Six rabbits without pellet implantation served as controls. Results: The hearts in the acute studies were paced with a pacing cycle length (PCL) of 200-300 ms and mapped at baseline and after administration of 1 nM, 10 nM, 100 nM, and 3 μM of testosterone. There was no shortening of APD80 at any PCL. Instead, a lengthening of APD80 was noted at higher concentrations. There were no sex differences in testosterone responses. In chronic studies, heart rates were 136 ± 5 bpm before and 148 ± 9 bpm after (P = .10) while QTc intervals were 314 ± 9 ms before and 317 ± 99 ms after (P = .69) testosterone pellet implantation, respectively. Overall, ventricular APD80 in the pellet group was longer than in the control group at 300- to 700-ms PCL. Conclusion: Testosterone does not shorten ventricular repolarization in rabbit hearts.