Testosterone

About: Testosterone is a research topic. Over the lifetime, 23258 publications have been published within this topic receiving 808079 citations. The topic is also known as: 4-androsten-17beta-ol-3-one & 4-Androsten-3-one-17b-ol.

Total Serum Testosterone and Gonadotropins in Workers Exposed to Dioxin

Abstract: Human reproductive endocrine data may be an important source of epidemiologic information in regard to the toxic potential of 2,3,7,8-tetrachlorodibenzo-p-dioxin (dioxin). The association of serum dioxin with total serum testosterone, luteinizing hormone, and follicle-stimulating hormone was examined in 248 chemical production workers from New Jersey and Missouri plants and 231 nonexposed neighborhood referents who participated in a medical evaluation in 1987. In linear regression analyses, current serum dioxin was positively and significantly related to luteinizing hormone and follicle-stimulating hormone and inversely related to total testosterone after adjustment for potential confounders (p 28 IU/liter), high follicle-stimulating hormone (> 31 IU/liter), and low testosterone (< 10.4 nmol/liter) by serum dioxin quartiles. There was a greater prevalence of high luteinizing hormone among workers in the second (odds ratio (OR) = 1.9, 95% confidence interval (CI) 0.7-5.5), third (OR = 2.5, 95% CI 0.9-7.3), and fourth (OR = 1.9, 95% CI 0.7-5.0) quartiles of serum dioxin compared with referents. For follicle-stimulating hormone, the authors observed a greater prevalence of high follicle-stimulating hormone among workers in the fourth quartile (OR = 2.0, 95% CI 0.7-5.6) compared with referents. Similarly, the prevalence of low testosterone was two to four times greater among workers in the second (OR = 3.9, 95% CI 1.3-11.3), third (OR = 2.7, 95% CI 0.9-8.2), and fourth quartiles (OR = 2.1, 95% CI 0.8-5.8) than among referents. The trends observed in these data offer human evidence of alterations in male reproductive hormone levels associated with dioxin exposure. The results support the animal literature in which dioxin-related effects have been observed on the hypothalamic-pituitary-Leydig-cell axis and on testosterone synthesis.

Significance of Aromatase Activity in Human Breast Cancer

Abstract: The significance of in vitro aromatization of [7 alpha-3H]testosterone to estradiol by human breast cancer has been investigated by correlation with (a) estrogen receptor activity and (b) clinical response to endocrine therapy. Evidence for estradiol synthesis was obtained in 66 and estrogen receptor activity in 81 of 110 tumors. Whereas most estrogen receptor-positive tumors synthesized estradiol, the majority of the receptor-negative tumors did not. This tendency for aromatization to be associated with estrogen receptor-positive tumors was statistically significant (p less than 0.005). Mean level of receptor was also significantly higher in tumors with aromatization than in tumors without estradiol synthesis (p less than 0.001). Forty patients with advanced breast cancer have been treated by endocrine therapy. There was a significant trend for tumors with aromatization to be associated with response to treatment (p less than 0.05), but the correlation was not absolute and may simply reflect the association between aromatase activity and estrogen receptors. Within the small subgroup of patients treated with aminoglutethimide or adrenalectomy, tumors with high aromatase activity responded whereas those without aromatization did not. Tumor estrogen biosynthesis may therefore be of clinical significance in selecting patients for treatments which remove sources of precursor for aromatization of inhibit aromatase activity itself.