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Query: UMLS:C0432222 (SEM)
 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We measured the concentrations of testosterone and its metabolites in serum and prostate glands of Nigerians, a low risk population for prostatic tumours, by means of radioimmunoassay after solvent and chromatographic extractions. Our results show that the values of serum testosterone in normal, elderly Nigerian men (447.0 +/- 112 ng./dl.) and those with benign prostatic hypertrophy (BPH) (430 +/- 112 ng./dl.) were similar (p greater than 0.05) and compare with values reported for Caucasians. In the Nigerian patients with advanced prostatic cancer, the serum testosterone concentrations (314 +/- 202 ng./dl.) were significantly lower (p less than 0.001) than those of Nigerians with normal prostate and BPH. This again is similar to reports in Caucasians with metastatic prostatic cancer. The serum concentrations of testosterone metabolites in our patients were the same in normal BPH and cancer subjects. The ratios of testosterone to its metabolites were similar in our normal and BPH subjects but lower in cancer patients. Also the testosterone concentrations in BPH glands of Nigerians (0.5 +/- 0.03 SEM ng./gm.) compared favourably with those reported from the western world. The testosterone concentrations in malignant prostate gland (7.9 +/- .06 SEM ng./gm.) were significantly higher than those in hypertrophic glands. This again agrees with the pattern in Caucasians. The DHT concentrations (4.9 +/- 0.3 SEM ng./gm.) were considerably higher in BPH than in cancerous glands (1.7 +/- 0.2 SEM ng./gm.). This pattern has been documented elsewhere. Because the concentrations and pattern of distribution of androgens in serum and prostate gland of our patients are comparable to published Caucasian and black American values, any difference in incidence rates of BPH and carcinoma of the prostate between whites, Afro-Americans and indigenous Africans may not be related to androgens.
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PMID:Androgen concentration in blacks with benign and malignant prostatic disease. 245 27

Prostate tissues from patients with benign prostatic hypertrophy were separated into epithelial and stromal components and the concentrations of zinc and cadmium were determined in these two fractions and in whole tissue by atomic absorption spectrophotometry. The concentrations of testosterone and 5 alpha-dihydrotestosterone (5 alpha-DHT) were determined by radioimmunoassays. The concentration of zinc was found to be significantly greater (P less than .001) in epithelial than in stromal preparations: 17.32 +/- 1.15 vs. 7.29 +/- 0.53 mumol/g dry weight (SEM, n = 15). The concentrations of cadmium in epithelium, 9.55 +/- 1.31 nmol/g dry weight (SEM, n = 15) and in stroma, 6.65 +/- 1.06 nmol/g dry weight (SEM, n = 15), did not differ significantly. The concentrations of zinc and cadmium in whole tissues were 13.88 +/- 1.70 mumol/g dry weight and 8.85 +/- 1.53 nmol/g dry weight, respectively (SEM, n = 15). In epithelial preparations, cadmium and testosterone were inversely correlated, but no other correlations were noted between metal and androgen concentrations in whole tissue, stroma, or epithelium. The results of the present study indicate that zinc preferably resides in the epithelium of human prostatic tissue, particularly in BPH, although the stroma also contains significant amounts of this metal. Cadmium appears to be more evenly distributed between the epithelium and stroma of prostatic tissue and previous findings of high cadmium concentrations in hypertrophic and carcinomatous prostatic tissue were not confirmed.
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PMID:Zinc and cadmium concentrations in whole tissue and in separated epithelium and stroma from human benign prostatic hypertrophic glands. 257 70

Plasma testosterone (T, nmol/l) and dihydrotestosterone (DTH, nmol/l) were measured in 54 children and young adults with male pseudohermaphroditism (46XY, no defect of steroid biosynthesis) 4 h after im injection of testosterone propionate (25 mg/m2, group 1, N = 18), or before and 2, 4 and 6 days after hCG (5000 IU/m2 im, group 2, N = 36). The response to hCG was also studied in 5 control children (unilateral cryptorchidism, group 3) and that to testosterone propionate in a gonadectomized child with confirmed 5 alpha-reductase deficiency. Mean T (133.1 +/- 14.0, SEM) and DHT (17.1 +/- 2.6) in group 1 were higher than in group 2 (17.3 +/- 2.1 and 2.9 +/- 0.4), but there was not significant difference in the T/DHT ratios (group 1: 10.7 +/- 2.0; group 2: 7.2 +/- 0.6). Following testosterone-propionate, there was a negative correlation of T with age (r = -0.723). After hCG, T and DHT were lower in the prepubertal children than in those under 2 or over 10 years, and the T/DHT-ratio rose with age. Two children from group 1 had a T/DHT-ratio above 18, but urinary aetiocholanolone/androsterone (Ae/A) ratios were normal. In the child with 5 alpha-reductase deficiency, the T/DHT ratio was 60, and the urinary Ae/A ratio high. We concluded that the two tests are suitable for confirming or excluding 5 alpha-reductase deficiency in prepubertal children, in whom basal DHT is too low for evaluation, but that physiological age-related changes in 5 alpha-reductase activity have to be taken into consideration.
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PMID:Comparison of two tests to recognize or exclude 5 alpha-reductase deficiency in prepubertal children. 288 Apr 42

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.
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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.
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PMID:Adrenal precursor C19 steroids are potent stimulators of growth of androgen-sensitive mouse mammary carcinoma Shionogi cells in vitro. 297 15

Available androgen binding to soluble proteins from the cytosol of human endometrium was studied using the dextran coated charcoal adsorption method and sucrose density centrifugation analysis. Specific binding of [3H]-5 alpha-dihydrotestosterone ([3H]-DHT) was observed with both methods. The apparent dissociation constant (Kd), for DHT binding is 1.3 +/- 0.2 (SEM) nM and the binding capacity 177 +/- 42 (SEM) fmol/mg protein. Sucrose density ultracentrifugation identifies specific [3H]-DHT binding that sediments at 4S and 8S. The stability of the androgen receptor in human endometrium is increased by the addition of 10% glycerol to the homogenization buffer. The addition of trypsin or pronase and heating at 60 degrees C reduces specific binding which demonstrates that the specific [3H]-DHT binder is a protein. The uptake of [3H] DHT in endometrial tissue minces indicated that 20% of the bound radioactivity was nuclear. Steroid specificity suggests that the binding protein from the uterus is specific for androgens. These observations indicate that androgen binding protein in the human uterus has the characteristics of the androgen receptor.
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PMID:The androgen receptor of the human endometrium. 358 78

The conversion of testosterone to estradiol by aromatase and to dihydrotestosterone by 5 alpha-reductase was measured in the medial basal hypothalamus of starved and control male rats. Activities of both enzymes were significantly reduced in starved animals. Aromatase activity was 18.2 +/- 2.3 versus 29.8 +/- 5.7 fmol E2/mg protein/90 min (mean +/- SEM, P less than 0.02) and 5 alpha-reductase was 4.95 +/- 0.35 versus 5.96 +/- 0.30 pmol DHT/mg protein/90 min (P less than 0.02) for starved and control animals respectively. The results indicate that hypothalamic metabolism of testosterone is decreased during starvation. Therefore the increased sensitivity of the T-LH feedback described earlier in starved rats [4] cannot be explained by changes in central testosterone metabolism.
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PMID:Testosterone metabolism in the medial basal hypothalamus of the starved male rat. 358 55

The serotonin (5-hydroxytryptamine, 5-HT) content of tissue compartments in the medicinal leech, Hirudo medicinalis, was measured by means of high-pressure liquid chromatography coupled with electrochemical detection (HPLC-EC). Each segmental ganglion contains 21.3 +/- 2.9 (9) pmol 5-HT [X +/- SEM (N)]. The pharynx contains 7.1 +/- 1.1 (9) pmol 5-HT/mg wet weight; the salivary glands 3.2 +/- 0.9 (10), ventral body wall 2.0 +/- 0.2 (11), and vasofibrous tissue 1.2 +/- 0.2 (11). The blood of hungry leeches contains 8.7 +/- 1.9 (7) nM 5-HT while that of well-fed leeches is 2.2 +/- 0.4 (6) nM. Leeches were injected with the cytotoxic analog of serotonin, 5,7-dihydroxytryptamine (5,7-DHT) producing selective lesions of the peripherally projecting serotonin-containing neurons, and which in turn abolished their feeding behavior. The serotonin content of the pharynx and ganglia of these toxin-treated leeches were lowered significantly. The serotonin levels within the body wall and salivary glands were not altered significantly by the toxin treatment, but the levels within the vasofibrous tissue and blood were elevated substantially.
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PMID:Quantitative effects of a neurotoxin upon serotonin levels within tissue compartments of the medicinal leech. 650 56

To investigate the relative effects of androgens and estrogens on long bone growth, we evaluated the 3-week ulnar growth velocities of 10 boys before and after the iv administration of testosterone (T; 15 mg/day), dihydrotestosterone (DHT; 7 mg/day), and estradiol (E2; 90 micrograms/day) for 4 days. Ulnar growth is a sensitive index of short term growth in children. Mean 3-week ulnar growth velocities increased from 0.49 +/- 0.11 (+/- SEM) to 1.09 +/- 0.14 mm/3 weeks after the T infusion (P less than 0.005), from 0.42 +/- 0.09 to 0.84 +/- 0.13 mm/3 weeks after the DHT infusion (P less than 0.02), and from 0.67 +/- 0.07 to 0.96 +/- 0.26 mm/3 weeks after the E2 infusion (P = NS). The mean T level was 2555 +/- 234 ng/dl during the T infusion. Mean E2 levels were 53 +/- 4 pg/ml during the T infusion and 102 +/- 7 pg/ml during the E2 infusion. Mean DHT levels were 73 +/- 7 ng/dl during the T infusion and 1115 +/- 124 ng/dl during the DHT infusion. Mean somatomedin-C levels increased to a similar degree during all infusions, but were significantly higher only during the E2 infusion (P less than 0.01). We conclude that T and DHT given for 4 days stimulated ulnar growth, while E2 at concentrations greater than those derived from T did not cause a significant increase in ulnar growth. None of the ulnar growth rates after T, DHT, or E2 treatment, however, differed significantly.
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PMID:The effects of sex steroids on ulnar growth during adolescence. 653 5

Partially-purified 5 alpha-dihydrotestosterone-receptor (DHT-R) complexes, extracted from normal genital skin fibrolasts (GSF) previously labelled with [3H]DHT, dissociate with monophasic kinetics and dissociation rate constants (k-2) of 10, 6, 3 and 2 x 10(-3) min-1 at 40, 37, 32 and 29 degrees C, respectively. An Arrhenius plot yields an activation energy of 28 kcal/mole. We studied 2 subjects who have constitutional androgen insensitivity (AI) despite a normal level of specific DHT-R activity in their GSF. Subject 1 has complete AI and unambiguous female external genitalia; subject 2 has partial AI and had ambiguous external genitalia at birth. In contrast to normal, the DHT-R complexes extracted from the GSF of these 2 subjects dissociate with biphasic kinetics. At 37 degrees C the k-1 of their early ('fast') component is 21 +/- 0.4(+/-SEM) x 10(-3) min-1(n = 7), while that of their late ('slow') component (k-2) is 7.8 +/- 0.3 x 10(-3) min-1 (n = 7). The latter value is very similar to the single k-2 (6.1 +/- 0.1 x 10(-3) min-1, n = 9) of the DHT-R complexes extracted from normal fibroblasts. When dissociation of DHT-R complexes is studied with intact fibroblasts, monophasic kinetics are observed for both the normal and mutant subjects. A k-1 of 18 x 10(-3) min-1 was previously observed for both mutant subjects at 37 degrees C (normal: K-2, 5.9 +/- 0.3 x 10(-3) min-1, n = 15). At 40 degrees C subject 1 has a rate constant of 25 while that of subject 2 is 50 x 10(-3) min-1(normal: 10 x 10(-3) min-1). An Arrhenius plot of the results from subject 1 yields an activation energy of 18 kcal/mole. The 2 sets of data suggest that inability of DHT-R complexes to transform from a rapidly dissociating to a slowly-dissociating form within intact target cells is a marker of genetic mutations that alter the androgen receptor and thereby cause certain types of partial of complete AI.
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PMID:Defective activation of androgen-receptor complexes: a marker of androgen insensitivity. 705 33


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