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Goetz SM, Tang L, Thomason ME, Diamond MP, Hariri AR, Carré JM. Testosterone rapidly increases neural reactivity to threat in healthy men: a novel two-step pharmacological challenge paradigm. Biol Psychiatry 2014; 76:324-31. [PMID: 24576686 PMCID: PMC9552187 DOI: 10.1016/j.biopsych.2014.01.016] [Citation(s) in RCA: 109] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2013] [Revised: 12/17/2013] [Accepted: 01/10/2014] [Indexed: 01/20/2023]
Abstract
BACKGROUND Previous research suggests that testosterone (T) plays a key role in shaping competitive and aggressive behavior in humans, possibly by modulating threat-related neural circuitry. However, this research has been limited by the use of T augmentation that fails to account for baseline differences and has been conducted exclusively in women. Thus, the extent to which normal physiologic concentrations of T affect threat-related brain function in men remains unknown. METHODS In the current study, we use a novel two-step pharmacologic challenge protocol to overcome these limitations and to evaluate causal modulation of threat- and aggression-related neural circuits by T in healthy young men (n = 16). First, we controlled for baseline differences in T through administration of a gonadotropin releasing hormone antagonist. Once a common baseline was established across participants, we then administered T to within the normal physiologic range. During this second step of the protocol we acquired functional neuroimaging data to examine the impact of T augmentation on neural circuitry supporting threat and aggression. RESULTS Gonadotropin releasing hormone antagonism successfully reduced circulating concentrations of T and brought subjects to a common baseline. Administration of T rapidly increased circulating T concentrations and was associated with heightened reactivity of the amygdala, hypothalamus, and periaqueductal grey to angry facial expressions. CONCLUSIONS These findings provide novel causal evidence that T rapidly potentiates the response of neural circuits mediating threat processing and aggressive behavior in men.
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Chen S, Wu R, Huang Y, Zheng F, Ou Y, Tu X, Zhang Y, Gao Y, Chen X, Zheng T, Yang Q, Wan Z, Zhang Y, Sun X, Liu G, Deng C. Insulin resistance is an independent determinate of ED in young adult men. PLoS One 2013; 8:e83951. [PMID: 24391852 PMCID: PMC3877124 DOI: 10.1371/journal.pone.0083951] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Accepted: 11/11/2013] [Indexed: 01/25/2023] Open
Abstract
Background Insulin resistance (IR) triggers endothelial dysfunction, which contributes to erectile dysfunction (ED) and cardiovascular disease. Aim To evaluate whether IR was related to ED in young adult patients. Methods A total of 283 consecutive men complaining of ED at least six months were enrolled, with a full medical history, physical examination, and laboratory tests collected. Quantitative Insulin Sensitivity Check Index (QUICKI) was used to determine IR. The severity of ED was assessed by IIEF-5 questionnaire. Endothelial function was assessed by ultrasonographic examination of brachial artery flow mediated dilation (FMD). Results IR was detected in 52% patients. Subjects with IR had significant higher total cholesterol, triglycerides, low density lipoprotein-cholesterol (LDL-c), glycated haemoglobin (HBA1c), high sensitivity C-reactive protein (hs-CRP) and body mass index (BMI), but showed significant lower IIEF-5 score, FMD%, high density lipoprotein -cholesterol (HDL-c), testosterone, sex hormone binding globulin (SHBG) levels than patients without IR. Multiple regression analysis showed QUICKI and testosterone were independent predictors of IIEF-5 score. Furthermore, the incidence of IR was correlated with the severity of ED. Conclusions Compared with other CVFs, IR was found as the most prevalent in our subjects. Besides, IR was independently associated with ED and its severity, suggesting an adverse effect of insulin resistance on erectile function.
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Affiliation(s)
- Shengfu Chen
- Department of Urology, First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, Guangdong Province, China
| | - Rongpei Wu
- Department of Urology, First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, Guangdong Province, China
| | - Yanping Huang
- Department of Urology, Shanghai Institute of Andrology, Renji Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
| | - Fufu Zheng
- Department of Urology, First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, Guangdong Province, China
| | - Yangbin Ou
- Department of Urology, First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, Guangdong Province, China
| | - Xiangan Tu
- Department of Urology, First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, Guangdong Province, China
| | - Yadong Zhang
- Department of Urology, First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, Guangdong Province, China
| | - Yong Gao
- Department of Urology, First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, Guangdong Province, China
| | - Xin Chen
- Department of Urology, First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, Guangdong Province, China
| | - Tao Zheng
- Department of Urology, First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, Guangdong Province, China
| | - Qiyun Yang
- Department of Urology, First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, Guangdong Province, China
| | - Zi Wan
- Department of Urology, First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, Guangdong Province, China
| | - Yuanyuan Zhang
- Wake Forest University, Institute for Regenerative Medicine, Winston-Salem, North Carolina, United States of America
| | - Xiangzhou Sun
- Department of Urology, First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, Guangdong Province, China
- * E-mail: (XS); (GL); (CD)
| | - Guihua Liu
- Department of Urology, First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, Guangdong Province, China
- Wake Forest University, Institute for Regenerative Medicine, Winston-Salem, North Carolina, United States of America
- * E-mail: (XS); (GL); (CD)
| | - Chunhua Deng
- Department of Urology, First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, Guangdong Province, China
- * E-mail: (XS); (GL); (CD)
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Pharmacokinetics of testosterone and estradiol gel preparations in healthy young men. Psychoneuroendocrinology 2013; 38:171-8. [PMID: 22721608 DOI: 10.1016/j.psyneuen.2012.05.018] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2012] [Revised: 05/25/2012] [Accepted: 05/25/2012] [Indexed: 11/23/2022]
Abstract
The paucity of pharmacokinetic data on testosterone gel formulations and absence of such data on estradiol administration in healthy young men constitutes a fundamental gap of knowledge in behavioral endocrinological research. We addressed this issue in a double-blind and placebo controlled study in which we applied a topical gel containing either 150mg of testosterone (N=10), 2mg of estradiol (N=8) or a respective placebo (N=10) to 28 healthy young men. We then assessed serum concentrations of estradiol and testosterone in one hour intervals up to seven hours after drug application, measured LH, SHBG and cortisol levels once at baseline and three, four as well as six hours after gel administration. Treatment with testosterone gel resulted in maximum total serum testosterone concentration three hours after administration and did not suppress LH, cortisol and SHBG levels at any time point. Administration of estradiol gel led to maximum estradiol serum concentration two hours after administration. There was no suppression of cortisol, SHBG and absolute LH levels. We report here, for the first time, pharmacokinetic data on both high dose testosterone and estradiol gel application in healthy young males. The proposed model will assist in the design of future studies that seek to establish causality between testosterone and estradiol gel administration and behavioral as well as neurophysiological effects.
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