About: Testosterone is a(n) research topic. Over the lifetime, 23258 publication(s) have been published within this topic receiving 808079 citation(s). The topic is also known as: 4-androsten-17beta-ol-3-one & 4-Androsten-3-one-17b-ol.
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TL;DR: Finasteride prevents or delays the appearance of prostate cancer, but this possible benefit and a reduced risk of urinary problems must be weighed against sexual side effects and the increased risk of high-grade prostate cancer.
Abstract: background Androgens are involved in the development of prostate cancer. Finasteride, an inhibitor of 5 a -reductase, inhibits the conversion of testosterone to dihydrotestosterone, the primary androgen in the prostate, and may reduce the risk of prostate cancer. methods In the Prostate Cancer Prevention Trial, we randomly assigned 18,882 men 55 years of age or older with a normal digital rectal examination and a prostate-specific antigen (PSA) level of 3.0 ng per milliliter or lower to treatment with finasteride (5 mg per day) or placebo for seven years. Prostate biopsy was recommended if the annual PSA level, adjusted for the effect of finasteride, exceeded 4.0 ng per milliliter or if the digital rectal examination was abnormal. It was anticipated that 60 percent of participants would have prostate cancer diagnosed during the study or would undergo biopsy at the end of the study. The primary end point was the prevalence of prostate cancer during the seven years of the study. results Prostate cancer was detected in 803 of the 4368 men in the finasteride group who had data for the final analysis (18.4 percent) and 1147 of the 4692 men in the placebo group who had such data (24.4 percent), for a 24.8 percent reduction in prevalence over the seven-year period (95 percent confidence interval, 18.6 to 30.6 percent; P<0.001). Tumors of Gleason grade 7, 8, 9, or 10 were more common in the finasteride group (280 of 757 tumors [37.0 percent], or 6.4 percent of the 4368 men included in the final analysis) than in the placebo group (237 of 1068 tumors [22.2 percent], P<0.001 for the comparison between groups; or 5.1 percent of the 4692 men included in the final analysis, P=0.005 for the comparison between groups). Sexual side effects were more common in finasteride-treated men, whereas urinary symptoms were more common in men receiving placebo. conclusions Finasteride prevents or delays the appearance of prostate cancer, but this possible benefit and a reduced risk of urinary problems must be weighed against sexual side effects and the increased risk of high-grade prostate cancer.
01 Sep 1959-Endocrinology
TL;DR: The sexual behavior of male and female guinea pigs from mothers receiving testosterone propionate during most of pregnancy was studied after the attainment of adulthood and the capacity to display lordosis following administration of estrogen and progesterone was greatly reduced.
Abstract: The sexual behavior of male and female guinea pigs from mothers receiving testosterone propionate during most of pregnancy was studied after the attainment of adulthood. As a part of the investigation, the responsiveness of the females to estradiol benzoate and progesterone and to testosterone propionate was determined. The larger quantities of testosterone propionate produced hermaphrodites having external genitalia indistinguishable macroscopicalty from those of newborn males. Gonadectomized animals of this type were used for tests of their responsiveness to estradiol benzoate and progesterone and to testosterone propionate. The capacity to display lordosis following administration of estrogen and progesterone was greatly reduced. Male-like mounting behavior, on the other hand, was displayed by many of these animals even when lordosis could not be elicited. Suppression of the capacity for displaying lordosis was achieved with a quantity of androgen less than that required for masculinization of the exte...
TL;DR: Levels of endogenous sex hormones are strongly associated with breast cancer risk in postmenopausal women, and SHBG was associated with a decrease in Breast cancer risk.
Abstract: Background: Reproductive and hormonal factors are involved in the etiology of breast cancer, but there are only a few prospective studies on endogenous sex hormone levels and breast cancer risk We reanalyzed the worldwide data from prospective studies to examine the relationship between the levels of endogenous sex hormones and breast cancer risk in postmenopausal women Methods: We analyzed the individual data from nine prospective studies on 663 women who developed breast cancer and 1765 women who did not None of the women was taking exogenous sex hormones when their blood was collected to determine hormone levels The relative risks (RRs) for breast cancer associated with increasing hormone concentrations were estimated by conditional logistic regression on case–control sets matched within each study Linear trends and heterogeneity of RRs were assessed by two-sided tests or chi-square tests, as appropriate Results: The risk for breast cancer increased statistically significantly with increasing concentrations of all sex hormones examined: total estradiol, free estradiol, non-sex hormone-binding globulin (SHBG)-bound estradiol (which comprises free and albumin-bound estradiol), estrone, estrone sulfate, androstenedione, dehydroepiandrosterone, dehydroepiandrosterone sulfate, and testosterone The RRs for women with increasing quintiles of estradiol concentrations, relative to the lowest quintile, were 142 (95% confidence interval [CI] = 104 to 195), 121 (95% CI = 089 to 166), 180 (95% CI = 133 to 243), and 200 (95% CI = 147 to 271; Ptrend<001); the RRs for women with increasing quintiles of free estradiol were 138 (95% CI = 094 to 203), 184 (95% CI = 124 to 274), 224 (95% CI = 153 to 327), and 258 (95% CI = 176 to 378; Ptrend<001) The magnitudes of risk associated with the other estrogens and with the androgens were similar SHBG was associated with a decrease in breast cancer risk (P trend = 041) The increases in risk associated with increased levels of all sex hormones remained after subjects who were diagnosed with breast cancer within 2 years of blood collection were excluded from the analysis Conclusion: Levels of endogenous sex hormones are strongly associated with breast cancer risk in postmenopausal women [J Natl Cancer Inst 2002;94:606–16]
01 Jun 2008-Cancer Research
TL;DR: Maximal therapeutic efficacy in the treatment of castration-resistant prostate cancer will require novel agents capable of inhibiting intracrine steroidogenic pathways within the prostate tumor microenvironment.
Abstract: Therapy for advanced prostate cancer centers on suppressing systemic androgens and blocking activation of the androgen receptor (AR). Despite anorchid serum androgen levels, nearly all patients develop castration-resistant disease. We hypothesized that ongoing steroidogenesis within prostate tumors and the maintenance of intratumoral androgens may contribute to castration-resistant growth. Using mass spectrometry and quantitative reverse transcription-PCR, we evaluated androgen levels and transcripts encoding steroidogenic enzymes in benign prostate tissue, untreated primary prostate cancer, metastases from patients with castration-resistant prostate cancer, and xenografts derived from castration-resistant metastases. Testosterone levels within metastases from anorchid men [0.74 ng/g; 95% confidence interval (95% CI), 0.59-0.89] were significantly higher than levels within primary prostate cancers from untreated eugonadal men (0.23 ng/g; 95% CI, 0.03-0.44; P < 0.0001). Compared with primary prostate tumors, castration-resistant metastases displayed alterations in genes encoding steroidogenic enzymes, including up-regulated expression of FASN, CYP17A1, HSD3B1, HSD17B3, CYP19A1, and UGT2B17 and down-regulated expression of SRD5A2 (P < 0.001 for all). Prostate cancer xenografts derived from castration-resistant tumors maintained similar intratumoral androgen levels when passaged in castrate compared with eugonadal animals. Metastatic prostate cancers from anorchid men express transcripts encoding androgen-synthesizing enzymes and maintain intratumoral androgens at concentrations capable of activating AR target genes and maintaining tumor cell survival. We conclude that intracrine steroidogenesis may permit tumors to circumvent low levels of circulating androgens. Maximal therapeutic efficacy in the treatment of castration-resistant prostate cancer will require novel agents capable of inhibiting intracrine steroidogenic pathways within the prostate tumor microenvironment.
TL;DR: It is demonstrated that early-life microbial exposures determine sex hormone levels and modify progression to autoimmunity in the nonobese diabetic (NOD) mouse model of type 1 diabetes (T1D), and Colonization by commensal microbes elevated serum testosterone and protected NOD males from T1D.
Abstract: Microbial exposures and sex hormones exert potent effects on autoimmune diseases, many of which are more prevalent in women. We demonstrate that early-life microbial exposures determine sex hormone levels and modify progression to autoimmunity in the nonobese diabetic (NOD) mouse model of type 1 diabetes (T1D). Colonization by commensal microbes elevated serum testosterone and protected NOD males from T1D. Transfer of gut microbiota from adult males to immature females altered the recipient's microbiota, resulting in elevated testosterone and metabolomic changes, reduced islet inflammation and autoantibody production, and robust T1D protection. These effects were dependent on androgen receptor activity. Thus, the commensal microbial community alters sex hormone levels and regulates autoimmune disease fate in individuals with high genetic risk.
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