Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0432222 (SEM)
 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The authors have measured the androgen receptor concentrations in the cytosol and nucleus of 13 carcinoma of the prostate (CaP) patients and compared these values to those in an age-matched group of 23 patients with benign prostatic hyperplasia (BPH). Histologic classification of the tumors was carried out and the receptor content was correlated to the grade and stage of the disease. The mean +/- SEM receptor values for BPH (cytosol: 115 +/- 18 fmol/g tissue; nucleus: 140 +/- 34 fmol/g tissue) were not significantly different from those measured in CaP (cytosol: 105 +/- 23 fmol/g tissue; nucleus: 83 +/- 23 fmol/g tissue). There was a positive correlation between nuclear and cytosolic receptors in both BPH and CaP. Our data revealed, however, the absence of any correlation between histologic grade in CaP and receptor content. If, however, the tumors were classified according to the stage of the cancer using the TNM system, "early disease" tumors maintained significantly lower Gleason score (4.4 +/- 0.61) and receptor levels (cytosol: 63.8 +/- 31.2 fmol/g tissue; nucleus: 46.2 +/- 26.5 fmol/g tissue) than those measured in the "late disease" (Gleason score: 7.0 +/- 0.56; cytosol receptor: 146.2 +/- 20.5; nuclear receptor: 117.2 +/- 31.6) (P less than 0.05); therefore the staging of the disease bears a great impact on the capacity of the tumor to specifically bind androgens.
 ...
PMID:Androgen receptors in cancer of the prostate. Correlation with the stage and grade of the tumor. 242 68

To investigate the role of somatostatin (SRIF) in regulating sexually dimorphic GH secretion, we used a reverse hemolytic plaque assay and acutely dispersed somatotropes from age-matched normal male, normal female, and androgen receptor-deficient, testicular feminized (Tfm) rats. Hemolytic plaques were developed after a 90-min incubation in the presence of GH antiserum, 10 nM GH-releasing hormone (GHRH), and the following concentrations of SRIF: 0, 0.001, 0.003, 0.01, 0.03, 0.1, 0.3, 1, 3, 10, 30, and 100 nM. Additional studies were performed with 0 or 100 nM SRIF in the absence of GHRH. The absolute number of somatotropes (x10(6); mean +/- SEM) recovered from the pituitaries of Tfm rats (1.73 +/- 0.18) was significantly greater than that from the males (1.11 +/- 0.13; P = 0.01); the number from female rats (1.30 +/- 0.15) was not different from that of either male or Tfm animals. GHRH-stimulated GH secretion, as estimated by the mean GH plaque area (micron2 x 10(4); mean +/- SEM) in the absence of SRIF, was greater for somatotropes from male rats (3.36 +/- 0.41) than that for either Tfm (2.27 +/- 0.32; P = 0.02) or female (1.78 +/- 0.24; P = 0.001) rats; values for the latter two groups did not differ. However, mean GH plaque areas for each group during maximal SRIF inhibition in either the presence or absence of GHRH were indistinguishable from each other and from mean plaque areas obtained under basal conditions. As demonstrated by a lesser EC50 value (0.04 +/- 0.02 nM; mean +/- SEM), somatotropes from female rats were more sensitive to the inhibitory effect of SRIF than were those from either male (EC50 = 1.82 +/- 0.45; P = 0.0001) or Tfm (EC50 = 0.74 +/- 0.22, P = 0.0001) rats; values for the latter two groups were indistinguishable. These observed differences suggest that gender and/or the gonadal hormone environment may be important determinants of the inhibitory effects of SRIF on GH secretion by the somatotrope. While these gender-associated differences may represent effects of the gonadal hormones directly on the somatotrope, they could reflect modulation of the secretion of hypothalamic SRIF and/or GHRH by the prevailing gonadal hormone environment. Such gender-related differences may contribute to the overall sex-dependent patterns of GH secretion in the intact animal.
 ...
PMID:Somatostatin inhibition of growth hormone secretion by somatotropes from male, female, and androgen receptor-deficient rats: evidence for differing sensitivities. 257 9

An estrogen stimulated increase in prostatic androgen receptor content has been postulated as the mechanism by which canine prostatic hyperplasia can be induced in the castrate dog treated with androstanediol and estradiol but not by androstanediol alone. In order to determine if the potent anti-estrogen Nafoxidine would inhibit this estrogen-associated development of prostatic hyperplasia, 2 week castrate young mongrel male dogs were injected for 1 month with either a) carrier solution (group 1), b) Nafoxidine (group 2), c) androstanediol and estradiol (group 3), or d) androstanediol and estradiol and Nafoxidine (group 4). At the termination of the experimental period the prostates of the animals in groups 1 and 2 were small (3.1 +/- 0.3 g (X +/- SEM) and 8.6 +/- 1.4 g respectively) and were atrophic histologically. The prostates in groups 3 and 4 were significantly heavier (24.7 +/- 3.0 g and 23.6 +/- 3.6 g respectively) than those in groups 1 and 2 and displayed glandular hyperplasia histologically. The dihydrotestosterone content of the prostatic tissue in groups 1 and 2 were similar (4.65 +/- 2.01 ng/mg DNA (X +/- SEM) and 3.13 +/- 0.65 ng/mg DNA respectively) and were significantly less than that of groups 3 and 4 (19.98 +/- 4.70 ng/mg DNA and 19.62 +/- 2.42 ng/mg DNA). The prostates of groups 3 and 4 thus displayed gravimetric, histologic and biochemical evidence of prostatic hyperplasia.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Androgen receptor content of nafoxidine treated experimentally induced canine prostatic hyperplasia. 258 Jun 56

To investigate the cellular mechanisms underlying the unique GH secretory apparatus of the androgen-resistant testicular feminized (Tfm) rat we employed a reverse hemolytic plaque assay to assess GH secretion by individual cells from normal male, normal female, and Tfm rats. Acutely dispersed pituitary cells were incubated for 90 min with GH anti-serum in the presence of medium alone, 0.01, 0.1, 1, 10, or 100 nM GHRH, or 3 microM forskolin after which hemolytic plaques were developed over an additional 30 min. Body weights of the Tfm rats [318 +/- 7 g (mean +/- SEM)] were intermediate between intact males (372 +/- 18 g) and females (218 +/- 7 g). The total number of cells recovered from dispersion of Tfm rat pituitaries [3.20 +/- 0.42 X 10(6) (mean +/- SEM)] was greater than that from males (1.43 +/- 0.12 X 10(6); P = 0.001), but not distinguishable from that from females (2.31 +/- 0.30 X 10(6); P = 0.06). However, the absolute population of recovered somatotropes from the Tfm animals (1.24 +/- 0.22 X 10(6) exceeded both male (0.56 +/- 0.10 X 10(6); P = 0.002) and female (0.80 +/- 0.14 X 10(6); P = 0.046) values. Mean basal and maximal GH plaque areas were greater for cells from male rats than for those from either female or Tfm rats (P less than 0.05) regardless of whether GHRH or forskolin was used as the secretagogue. Plaque areas from female and Tfm cells were indistinguishable under all study conditions. These data suggest that a deficiency of androgen receptors prevents establishment of the greater GH secretory capacity of individual somatotropes characteristic of the adult male rat. This androgen receptor-dependent modulation of GH secretory capacity appears to occur at a step distal to the GHRH receptor. The data also suggest that an increase in the absolute population of somatotropes is an additional consequence of androgen receptor deficiency. This combination of individual somatotropes, each possessing a GH secretory capacity similar to that of cells from normal females, but present in greater absolute numbers, may explain the intermediate values found during previous studies of the Tfm rat GH axis which were based on assessment of large mixed populations of pituitary cells.
 ...
PMID:Growth hormone secretion by individual somatotropes of the testicular feminized rat. 264 10

In order to study the regulation of aromatase activity by androgens in cultured fibroblasts derived from genital skin of normal prepubertal boys, aromatase activity was evaluated in the presence of various concentrations of non-aromatizable androgen DHT(5 alpha-dihydrotestosterone). The estrogen formation was assayed by an enzymatic method, after 24 h incubation of the cells with 10(-6) M androstenedione. Aromatase activity was stimulated 3- to 20-fold by DHT at concentrations 10(-10) and 10(-9) M. It was necessary to preincubate the cells with DHT for 48 h in order to bring about this stimulation. The stimulatory effect was not significant after preincubation for only 24 h. The basal value of aromatase activity was in the range of 8 +/- 1.2 pmol/mg protein/day (mean +/- SEM), while the maximal stimulation 1043 +/- 46 pmol/mg protein/day was obtained at the concentration of 10(-8) M DHT. This stimulation was partially blocked with cyproterone acetate at level of 20 +/- 4 pmol/mg protein/day; stimulation of aromatase activity by DHT could thus be mediated by the androgen receptor. This stimulatory effect was prevented by incubation of the cells with cycloheximide or actinomycin D, suggesting that DHT acts to increase aromatase activity in cultured fibroblasts by inducing the synthesis of new proteinaceous material. In vitro regulation of aromatase activity by androgens could contribute to a new approach to the extraglandular formation of estrogen.
 ...
PMID:Stimulation of aromatase activity by dihydrotestosterone in human skin fibroblasts. 294 41

Since there is convincing evidence for a role of adrenal steroids as precursors of active sex steroids in peripheral tissues, especially prostate cancer, we have studied the effect of the four main adrenal steroids, namely dehydroepiandrosterone sulfate (DHEA-S), DHEA, 5-androstene-3 beta,17 beta-diol (delta 5-diol) and 4-androstene-3,17-dione (delta 4-dione) on the growth of an androgen-sensitive clone (SEM-1) of the mouse mammary carcinoma Shionogi. From a control doubling time of 6.69 +/- 0.03 days, 0.1 microM DHT, 1.0 microM delta 4-dione, 10 microM delta 5-diol, 10 microM DHEA-S and 10 microM DHEA decreased generation time to 1.60 +/- 0.01, 1.69 +/- 0.01, 1.95 +/- 0.01, 4.37 +/- 0.02 and 5.66 +/- 0.03 days, respectively (P less than 0.01 vs. control). The same compounds exerted their stimulatory effects on cell growth at the following ED50 values: 0.06 nM, 16 nM, 90 nM, 150 nM and 16 microM for DHT, delta 4-dione, DHEA, delta 5-diol and DHEA-S, respectively. The stimulatory effect of all compounds was inhibited in a competitive manner by the pure antiandrogen hydroxyflutamide. Further evidence for an action of the adrenal steroids through the androgen receptor is indicated by competition of [3H]testosterone uptake in the tumor cells at the following IC50 values: 0.21 nM, 0.63 nM, 50 nM, 75 nM and 680 nM for DHT, testosterone, delta 4-dione, delta 5-diol and DHEA, respectively. The present data show that the four main adrenal steroids present in the serum of adult men can exert potent stimulatory effects on the growth of an androgen-sensitive cancer cell line through an androgen receptor-mediated mechanism.
 ...
PMID:Adrenal precursor C19 steroids are potent stimulators of growth of androgen-sensitive mouse mammary carcinoma Shionogi cells in vitro. 297 15

Androgen insensitivity has been reported to be present in as many as 40% of patients with severe oligospermia. In order to evaluate further the role of androgen resistance in male infertility we studied 24 men with severe oligospermia. Plasma T and LH were measured by RIA and the T X LH product was calculated. Fibroblasts were grown from genital skin obtained during testicular biopsies and androgen receptor maximal binding capacity (BMAX) and affinity (KD) were measured in fibroblast monolayers. Pubic skin 5 alpha-reductase activity, an androgen-dependent enzyme, was measured in skin homogenates. Plasma T values were in the upper normal range [7.0 +/- 1.7 (SEM) ng ml-1] whereas the T X LH product was high (greater than 50) in only six patients. Mean BMAX and KD values for the androgen receptor were normal [BMAX: 788 +/- 259 fmol mg DNA-1 (patients, n = 20), 726 +/- 227 (normal men, n = 20), and KD: 0.27 +/- 0.24 (patients, n = 20), 0.18 +/- 0.09 (normal men, n = 15), respectively]. However, four men had supranormal KD values. The mean BMAX was also normal when the group of men with sperm densities below 10(6) per ejaculate was considered separately. Public skin 5 alpha-reductase activity was normal in all but four patients (patients: 177.1 +/- 91 fmol/mg skin/h, n = 30, normal men: 210 +/- 45, n = 20 patients). In conclusion, androgen receptor BMAX levels were normal in all patients studied, regardless of the sperm density and the T X LH product. Pubic skin 5 alpha-reductase activity was also normal in all but four patients. In these four patients, a qualitative defect of the androgen receptor cannot be excluded. In this group of patients with severe oligospermia, infertility did not seem to be related to quantitative abnormality of the androgen receptor as was previously reported.
 ...
PMID:Androgen insensitivity in oligospermic men: a reappraisal. 309 23

Labeled methyltrienelone was used to determine androgen receptor (AR) levels in cultured pubic skin fibroblasts in 40 infertile men with primary seminiferous tubule disorders and 18 normal men. LH pulse patterns and mean serum LH levels were also determined by blood sampling at 10-min intervals for 6 h. The infertile men and the normal men had similar mean receptor levels [mean, 28.1 +/- 2.0 (+/- SEM) and 24.8 +/- 1.8 fmol/mg protein, respectively]. However, 5 men with chromosomal disorders had a higher mean AR level (41.3 +/- 6.2 fmol/mg protein) than the normal men, and 5 of the remaining infertile men (14.2%) had receptor levels that were less than the minimum value in normal men. In men with idiopathic oligospermia, 19.0% had low receptor levels. Although mean serum FSH and testosterone levels were similar in the infertile men with low AR levels and in the normal men, mean LH levels were significantly elevated in this group (7.1 vs. 3.6 IU/L), the higher values being a result of increased LH pulse amplitude (mean, 5.6 vs. 2.8 IU/L). The LH-testosterone product (an index of androgen resistance) was also elevated in these men. When infertile men with low AR levels were matched with infertile men with normal receptor levels, the mean LH values were significantly elevated in the former, as was the LH-testosterone product. Testosterone values were similar in the two groups of men. After excluding subjects with chromosomal disorders, there were no significant correlations between AR levels and other indices of androgen action, such as semen volume, seminal fructose, or sex hormone-binding globulin levels. We conclude that AR levels are higher in patients with severe testicular failure associated with X-chromosome disorders. Also, AR defects were found in 19.0% of infertile men with idiopathic oligospermia. Finally, elevation of mean LH levels in men with seminiferous tubule disorders may reflect resistance to androgen action.
 ...
PMID:Variable androgen receptor levels in infertile men. 310 95

Increasing concentrations of 17 beta-estradiol (E2) led to a maximal 7-fold stimulation of growth of the highly androgen-sensitive clone (SEM-1) of the mammary carcinoma Shionogi cell line. Half-maximal stimulation by the estrogen was observed at 100 nM E2. Diethylstilbestrol (DES), on the other hand, a synthetic estrogen with no affinity for the androgen receptor, had no significant stimulatory effect on cell growth but caused growth inhibition at concentrations above 1 microM. Mediation of the action of E2 by the androgen receptor is indicated by the absence of interference of E2 action by the antiestrogen LY156758 while the antiandrogen hydroxyflutamide (3 microM) caused a 50% inhibition of E2 action. While increasing concentrations of E2 led to a progressive increase in cell growth, a progressive shift in the ED50 value of action of dihydrotestosterone (DHT) was observed at intermediate (10-100 nM) concentrations of E2 while 10 microM E2 completely inhibited DHT action. At those high E2 concentrations, however, E2 itself led to a stimulation of cell growth equivalent to approximately 50% of the maximal value achieved by DHT. E2 competed with the specific uptake of [3H]testosterone in intact cells at an inhibition constant (Ki) value of 15 nM, thus indicating direct interaction of E2 with the androgen receptor. Preincubation with E2 had no influence on the apparent affinity of testosterone for the androgen receptor nor on the number of androgen binding sites. The present data demonstrate that both the stimulatory and antiandrogenic action of E2 on the growth of the androgen-sensitive mammary carcinoma cell line SEM-1 are mediated through direct interaction of the estrogen with the androgen receptor. Such data may offer an explanation for the subjective improvements reported in prostate cancer patients receiving a high dose of E2 when relapsing after castration.
 ...
PMID:Mediation by the androgen receptor of the stimulatory and antiandrogenic actions of 17 beta-estradiol on the growth of androgen-sensitive Shionogi mammary carcinoma cells in culture. 340 89

The in vitro binding of a synthetic androgen, methyltrienolone ([3H]-R1881), to brain and pituitary (PIT) cytosol and nuclear extracts was determined in male and female rats. Purified cytosol was prepared from PIT or hypothalamic-preoptic area-amygdala (HPA) and incubated in the presence of 0.1 to 10 nM [3H]-R1881. Scatchard analysis revealed the presence of a single, saturable, high-affinity binding site in PIT cytosol with a dissociation constant (Kd) of 0.42 X 10(-10) M in females and 0.95 X 10(-10) M in intact males. The Kd of HPA cytosol was much less in castrated males [0.47 +/- 0.05 (SEM) X 10(-10)M, n = 7] and females (0.63 +/- 0.1 X 10(-10) M, n = 4) than in intact males (5.8 +/- 1.1 X 10(-10) M, n = 8). Treatment of castrated males with dihydrotestosterone (DHT) for 24 h (250 micrograms/100 g of body weight) increased the Kd of HPA cytosol only slightly (1.6 X 10(-10) M, mean of two replicates). Scatchard analysis of salt-extracted nuclear androgen receptor (ARn) showed a single, high-affinity binding site with similar Kd values in PIT and HPA of intact and castrated, DHT-treated male rats (PIT Kd = 7.3 X 10(-10) M, 9.3 X 10(-10) M; HPA Kd = 1.5 X 10(-9) M, 1.3 X 10(-9) M, respectively). Competition studies involving a range of several radioinert steroids revealed that the binding of [3H]-R1881 to cytosol (ARc) and nuclear extract was specific for androgen receptor when triamcinolone acetonide (10 microM) was added. The ARc and ARn levels were quantified in PIT, preoptic area (POA), hypothalamus (HT), amygdala, hippocampus, and cortex by single point estimation. Significantly (p less than 0.01) greater amounts of ARc were detected in PIT of ovariectomized females (32.7 +/- 2.9 fmol/mg of protein) than in that of orchidectomized males (22.33 +/- 1.6 fmol/mg of protein). The highest levels in the brain were seen in HT and POA. Pituitary ARc in females varied throughout the estrous cycle. Significantly (p less than 0.01) greater amounts were detected on estrus (45.8 +/- 2.2 fmol/mg of protein) and proestrus (39.0 +/- 1.9 fmol/mg of protein) than on diestrus (29.2 +/- 1.5 fmol/mg of protein). These data confirm the existence of specific receptors for androgen in male and female brain and PIT, and suggest an important role for androgen in the control of PIT hormone secretion in the female.
 ...
PMID:Androgen receptors in brain and pituitary of female rats: cyclic changes and comparisons with the male. 348 49


1 2 3 Next >>