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.

Regulation of growth and epidermal growth factor receptor levels of LNCaP prostate tumor cells by different steroids.

Abstract: The growth of LNCaP cells, derived from a lymph-node carcinoma of the human prostate, was stimulated by different hormones. Optimal growth (3- to 4-fold increase in DNA content per culture versus controls) was observed at 0.1 nM R1881 (a synthetic androgen), 1 nM progesterone or 10 nM estradiol. Triamcinolone acetonide had no effect. Dihydrotestosterone maximally stimulated cell growth at 10 nM. When the culture medium was changed 4 times in 6 days instead of twice, optimal growth was observed at 1 nM dihydrotestosterone. This indicates that a rapid metabolism of dihydrotestosterone influenced growth response. LNCaP cells contained considerable amounts of androgen receptors (920 fmol/mg cytosol protein) while progestagen, estrogen and glucocorticoid receptors were absent. The affinity of steroids for the androgen receptor decreased in the order of: R1881 (relative binding affinity: 100.0) greater than dihydrotestosterone (67.7) greater than progesterone (29.4) greater than testosterone (23.8) greater than estradiol (4.3) greater than triamcinolone acetonide (less than 0.1). Effects on cell growth of these steroids paralleled their affinity for the androgen receptor. The number of EGF receptors per cell increased in a dose-dependent manner upon treatment with various hormones. Again the amount of steroid needed for maximal effects reflected the affinity of the steroid for the androgen receptor. An approximately 2-fold increase in EGF receptor number was observed within 24 hr and before an increase in growth could be detected. Actinomycin-D and cycloheximide inhibited the hormonally induced increase in EGF receptor numbers.

Paradoxical effects of maternal stress on fetal steroids and postnatal reproductive traits in female mice from different intrauterine positions.

Abstract: We examined effects of maternal stress on prenatal serum concentrations of testosterone and estradiol and on postnatal reproductive traits in female mice from different intrauterine positions. On Day 18 of fetal life, control females positioned in utero between two male fetuses (2M females) had higher concentrations of testosterone and lower concentrations of estradiol in serum than control female fetuses located between two females (0M females). Control females positioned between a male and a female fetus (1M females) had intermediate levels of both hormones. Prior intrauterine position in control females accounted for differences in genital morphology (length of the anogenital separation) at birth and length of estrous cycles during adulthood. Maternal stress eliminated these postnatal differences due to prior intrauterine position: all 0M, 1M, and 2M female offspring of stressed mothers exhibited postnatal traits that were indistinguishable from those of control 2M females. Maternal stress resulted in an increase of over 1 ng/ml in serum testosterone in all female fetuses; the magnitude of the increase was similar for 0M, 1M, and 2M females. There was no effect of maternal stress on serum concentrations of estradiol in 0M and 2M female fetuses. Maternal stress resulted in a dramatic change in the postnatal traits of 0M females, whereas 2M females showed no change. Since the effect of maternal stress on sex steroids was similar among fetuses from different intrauterine positions but postnatal response to maternal stress varied by intrauterine position, other components of the endocrine system may mediate effects of maternal stress on these postnatal characteristics.

Effects of valproate, phenobarbital, and carbamazepine on sex steroid setup in women with epilepsy.

Abstract: Serum levels of sex-hormones, sex-hormone binding globulin, gonadotropin, and prolactin were evaluated during the follicular and the luteal phases in 65 women with epilepsy and in 20 healthy controls. Twenty-one patients were treated with sodium valproate (VPA), 21 with phenobarbital (PB), and 23 with carbamazepine (CBZ). VPA does not stimulate liver microsome enzymes, whereas PB and CBZ do. Patients on VPA therapy showed higher body weight and body mass index, but no significant differences in hirsutism score, or in ovary volume or polycystic ovary prevalence (at ultrasound examination). Estradiol levels were lower in all patient groups than in healthy controls in the follicular but not in the luteal phases. VPA affected luteal progesterone surge in 63.6% of cases. This effect was significantly lower in the CBZ and PB groups. Furthermore, increases in testosterone and delta 4-androstenedione levels and in free androgen index, along with a higher luteinizing hormone-follicle-stimulating hormone ratio in the luteal phase, were observed in women treated with VPA. Although sex-hormone binding globulin levels were higher in CBZ and PB than in VPA-treated patients, the differences were not significant because of the wide dispersion of the carrier protein levels. Inducer antiepileptic drugs decreased dehydroepiandrosterone sulfate levels, which remained unchanged during VPA treatment. No significant differences occurred in basal gonadotropin and prolactin levels.