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.

Pituitary-Gonadal Relations in Infancy: 2. Patterns of Serum Gonadal Steroid Concentrations in Man from Birth to Two Years of Age

Abstract: Testosterone, estradiol, 17OH-progesterone, and androstenedione (except in cord samples) concentrations were determined in cord sera (30 male and 14 female) and in peripheral sera from infants (121 male and 110 female), age 1 day to 2 years. Male and female cord serum levels of these steroids were not significantly different. In both sexes levels during the first week were lower than those in cord sera. In male infants serum testosterone and 17OH-progesterone levels rose sharply in die second week of life, reached a peak at 1–2 months, and then declined to the range seen in later childhood by 6 months of age; male serum androstenedione and estradiol concentrations were higher during the first 2 months of life, but no distinct pattern of rise and fall was seen. In girls serum testosterone levels fell in the first week to the range seen throughout childhood; serum concentrations of estradiol, androstenedione, and 17OH-progesterone in girls were markedly variable, with many values above the childhoo...

Androgen Receptor Gene Expression in the Primate Ovary: Cellular Localization, Regulation, and Functional Correlations

Abstract: Excess androgens are associated with a characteristic polyfollicular ovarian morphology; however, it is not known to what extent this problem is due to direct androgen action on follicular development vs. interference with gonadotropin release at the level of the pituitary or hypothalamus. To elucidate potential androgen effects on the ovary, we investigated the cellular localization of androgen receptor (AR) messenger ribonucleic acid (mRNA) in rhesus monkey using in situ hybridization. To investigate the regulation of ovarian AR gene expression, we compared the relative abundance of AR transcripts in monkeys during follicular and luteal phases of the menstrual cycle and in monkeys treated with testosterone. To assess potential functional consequences of AR expression in the primate ovary, we compared AR mRNA levels with indexes of follicular cell proliferation and apoptosis in serial sections from individual follicles. AR mRNA expression was most abundant in granulosa cells of healthy preantral and antr...

A biological profile of a nonsteroidal antiandrogen SCH 13521 (4-nitro-3-trifluoromethylisobutyranilide).

Abstract: Sch 13521 (4'–nitro–3'–trifluoromethylisobutyranilide) at daily doses from 1–50 mg/kg reduced seminal vesicles and ventral prostate wt of intact male rats treated orally for 1–3 weeks. No alterations in sex structures of female rats were observed with doses as high as 50 mg/kg. Sch 13521 antagonized the effects of testosterone, testosterone propionate, androstenedione, and dihydrotestosterone on seminal vesicles and ventral prostate wt in castrated rats as well as the effects of hCG in hypophysectomized rats. A comparative study in castrated rats revealed that Sch 13521 was equipotent to cyproterone acetate (CPA) as an antiandrogen. However, when Sch 13521 was given to gravid rats, days 16–19, it reduced the anogenital distance in male fetuses and altered the normal development of the scrotum and penis, but unlike CPA, Sch 13521 did not effect parturition time. In the majority of these male rats, hypospadias and vaginal tracts were present and ventral prostates and seminal vesicles were absent or markedly...

Serum Sex Hormone Levels After Menopause and Subsequent Breast Cancer

Abstract: Background : High levels of androgens and estrogens have been reported to be associated with breast cancer. However, the multiplicity of factors that influence hormone levels and methodologic issues complicate the study of the relationship between steroid sex hormones and breast cancer. Purpose : Using an improved study design, we assessed prospectively the relationship between the principal steroid sex hormones in serum and the subsequent occurrence of invasive breast cancer in postmenopausal women. Methods : Four thousand fifty-three healthy postmenopausal women, aged 40-69 years, were enrolled from June 1987 through June 1992 in a prospective investigation of hormones and diet in the etiology of breast tumors (ORDET study) as part of a larger volunteer cohort of 10 788 premenopausal and postmenopausal women from Varese Province, northern Italy. At recruitment, blood samples were taken between 8 :00 AM and 9 :30 AM (after overnight fasting), and sera were preserved in -80 °C freezers. Women who had received hormone treatment in the 3 months prior to enrollment, who had a bilateral ovariectomy, or who had a history of cancer or liver disease were not recruited. Twenty-five women in the final eligible cohort of 4040 postmenopausal women developed histologically confirmed, invasive breast cancer during the first 3.5 years of follow-up for the cohort (13 537 woman-years). For each case subject, four control subjects were randomly chosen after matching for factors possibly affecting hormone preservation in serum. One case subject and eight control subjects were excluded because premenopausal hormonal patterns were found ; thus, after also excluding the four control subjects matched to the ineligible case subject, we included 24 case and 88 control subjects. In the spring of 1994, stored sera of case and control subjects were assayed in a blinded manner for dehydroepiandrosterone sulfate and estradiol (E 2 ) by in-house radioimmunoassay and for total and free testosterone and sex hormone-binding globulin by commercially available nonextraction iodination kits. Mean differences in risk factors were tested by analysis of variance for paired data. Relative risks (RRs) were estimated by conditional logistic regression analysis. All P values resulted from two-sided tests. Results : Age-adjusted mean values of total testosterone, free testosterone, and E 2 were significantly higher in case subjects than in control subjects : total testosterone, 0.34 ng/mL versus 0.25 ng/mL (P<.001) ; free testosterone, 1.07 pg/mL versus 0.77 pg/mL (P =.006) ; and E 2 , 25 pg/mL versus 22 pg/mL (P = .027). Age-adjusted RRs for breast cancer in increasing tertiles were as follows: for total testosterone, 1.0, 4.8, and 7.0 (P for trend =.026) ; for free testosterone, 1.0, 1.8, and 5.7 (P for trend =.005) ; and for total E 2 , 1.0, 7.1, and 5.5 (P for trend =.128). Conclusions and Implications : This prospective study provides further evidence in support of the already established association between elevated estrogen levels and breast cancer. Even more importantly, it provides new evidence that high serum testosterone levels precede breast cancer occurrence

Quantitative studies of prostatic secretion : ii. the effect of castration and of estrogen injection on the normal and on the hyperplastic prostate glands of dogs.

Abstract: Cystic hyperplasia of the prostate occurs spontaneously in senile dogs only when they possess physiologically effective amounts of androgenic hormone. The cysts are closely grouped and radially arranged in a conical manner with the base of the cone at the periphery of the gland. Flattened and columnar epithelium, varying from about 5 to 25micro are seen in each cyst. The cysts communicate with the urethra by way of ducts. Both normal and cystic prostates undergo marked atrophy when the testes are removed, the chief difference 3 months after orchiectomy being the persistence of slightly dilated clefts and spaces at the site of the former cysts in the senile state. In the castrate dog whose prostate gland is being reconstructed as result of the influence of daily injections of androgen, certain doses of estrogen prevent increase of secretion and still larger doses greatly depress the output of the gland. In dogs so treated by daily injections of testosterone propionate, 10 mg., the amount of secretion is maintained from day to day at a level by daily injections of stilbestrol, 0.4 to 0.6 mg. and greatly depressed by doses of 1 to 1.5 mg. When the larger amounts of estrogen are used, together with androgen, squamous metaplasia occurs in the posterior lobe of the prostate while the epithelium of the acini decreases in height to cuboidal or low columnar form; these histological signs of activity of both androgen and estrogen on the prostate show that inhibition of the male hormone by stilbestrol is incomplete at these ratios. In dogs with either normal or cystic prostate glands, the prostate decreases in size when estrogen is injected in amounts to depress prostatic secretion profoundly. The gland is maintained in an atrophic state and overdosage avoided by controlled periodic injections of stilbestrol until secretion is reduced to the minimum, followed by free intervals, the estrogen being again administered when secretion measurably increases. The shrinkage is related to depression of male hormone production. Overdosage of estrogen causes the prostate gland of dogs to enlarge, and structures of the posterior lobe and utriculus respond first and most markedly with metaplasia caused by this material. The prostatic enlargement does not resemble the common cystic hyperplasia of senile dogs. Metaplasia rapidly disappears from the prostate, and the epithelial structures quickly return to normal when estrogen is discontinued and androgen is administered.