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Publication
Journal: Analytical and Bioanalytical Chemistry
July/22/2013
Abstract
This study describes an on-line stacking CE approach by sweeping with whole capillary sample filling for analyzing five anabolic androgenic steroids in urine samples. The five anabolic steroids for detection were androstenedione, testosterone, epitestosterone, boldenone, and clostebol. Anabolic androgenic steroids are abused in sport doping because they can promote muscle growth. Therefore, a sensitive detection method is imperatively required for monitoring the urine samples of athletes. In this research, an interesting and reliable stacking capillary electrophoresis method was established for analysis of anabolic steroids in urine. After liquid-liquid extraction by n-hexane, the supernatant was dried and reconstituted with 30 mM phosphate buffer (pH 5.00) and loaded into the capillary by hydrodynamic injection (10 psi, 99.9 s). The stacking and separation were simultaneously accomplished at -20 kV in phosphate buffer (30 mM, pH 5.0) containing 100 mM sodium dodecyl sulfate and 40 % methanol. During the method validation, calibration curves were linear (r≥0.990) over a range of 50-1,000 ng/mL for the five analytes. In the evaluation of precision and accuracy for this method, the absolute values of the RSD and the RE in the intra-day (n=3) and inter-day (n=5) analyses were all less than 6.6 %. The limit of detection for the five analytes was 30 ng/mL (S/N=5, sampling 99.9 s at 10 psi). Compared with simple MECK, this stacking method possessed a 108- to 175-fold increase in sensitivity. This simple and sensitive stacking method could be used as a powerful tool for monitoring the illegal use of doping.
Publication
Journal: Comptes rendus hebdomadaires des seances de l'Academie des sciences. Serie D: Sciences naturelles
May/27/1966
Publication
Journal: Endocrinologia experimentalis
March/26/1980
Abstract
19-Nortestosterone was identified as a product of testosterone conversion in vitro in male mouse kidney. After incubation of [14C]testosterone with kidney slices of castrated male mice, 64% of the radioactivity was recovered as testosterone, about 6% as epitestosterone and 2.5% was identified as 19-nortestosterone. The renotrophic effect of 19-nortestosterone was at least as high as that of testosterone. Possible role of 19-nortestosterone in mouse kidney is discussed.
Publication
Journal: International Journal of Legal Medicine
October/30/2017
Abstract
We developed and validated a method to detect and quantify 12 anabolic steroids in blood (androstenedione, dihydrotestosterone, boldenone, epitestosterone, mesterolone, methandienone, nandrolone, stanozolol, norandrostenedione, tamoxifene, testosterone, trenbolone) and eight more in hair samples (nandrolone phenylpropionate, nandrolone decanoate, testosterone propionate, testosterone benzoate, testosterone cypionate, testosterone decanoate, testosterone phenylpropionate, testosterone undecanoate) using liquid chromatography coupled to high-resolution mass spectrometry. This method used a benchtop Orbitrap mass spectrometer operating with an APCI probe under positive ionization mode. Analysis was realized in full scan experiment with a nominal resolving power of 140,000. After addition of the internal standard (testosterone-D3) and incubation in phosphate buffer pH = 5 for hair, 200 μL of blood and 30 mg of hair samples were extracted with heptane. LOQ and LOD were determined at 5 and 1 ng mL-1 in whole blood and 10 to 100 pg mg-1 and 2 to 20 pg mg-1 in hair according to the compounds, respectively. The method was linear in the 5-1000 ng mL-1 range in whole blood and between 10 or 100 pg mg-1 and 1000 pg mg-1 in hair with correlation coefficients >0.99, and intra- and inter-day accuracy and precision were <14.8% for all compounds except for some esters in hairs (<19.9%) probably due to an important matrix effect for these compounds. This sensitive and specific method to detect anabolic steroids has been successfully applied to two real cases, for which various anabolic steroids in whole blood, urine, and hair were identified and quantified.
Publication
Journal: General and Comparative Endocrinology
May/9/2011
Abstract
Testosterone regulates a wide variety of behavioral and physiological traits in male vertebrates. It influences reproductive and aggressive behaviors and is used as a marker of gonadal activity. While testosterone is the primary biologically active male gonadal steroid in the blood, it is metabolized into a variety of related steroids when excreted via urine and feces. To monitor endocrinological profiles studies on wild-living animals primarily rely on non-invasively collected samples such as urine or feces. Since a number of androgen metabolites that are found in high concentrations in these matrices do not stem exclusively from gonadal production, but are also produced by the adrenal cortex, the metabolism and excretion pattern of testosterone and its characteristic metabolites have to be investigated. Here, we compare the levels of 11 androgens and their metabolites in serum and urine (after hydrolytic/solvolytic cleavage of conjugates) from female, and intact and castrated male chimpanzees to investigate whether they were of testicular or adrenal origin. For serum, significant differences in concentrations were found only for native testosterone. For urine, testosterone concentrations showed the largest differences between intact and castrated males, and intact males and females, while no differences were seen between females and castrated males. Epitestosterone levels revealed the same pattern. These differences in urinary concentrations could also be seen for 5α-androstane-3α,17β-diol (androstanediol), and less clearly for 5α-dihydrotestosterone (5α-DHT), etiocholanolone, and androsterone. In urine of males, significant correlations were found between the levels of testosterone and 5α-androstane-3α,17β-diol, as well as between testosterone and epitestosterone. Therefore, the clearest urinary markers of gonadal activity in male chimpanzees seems to be testosterone itself.
Publication
Journal: Journal of Steroid Biochemistry and Molecular Biology
February/13/1996
Abstract
Epitestosterone has for a long time been considered as a biologically inactive steroid. However, recently a distinct antiandrogenic activity of this naturally occurring endogenous epimer of testosterone has been demonstrated. Epitestosterone plays a role in the control of doping with testosterone, since an arbitrary ratio of testosterone to epitestosterone in urine has been accepted as a marker for testosterone abuse. For this reason, its urinary excretion has been examined intensively by several authors. On the other hand, its concentration in the blood of men was reported only randomly in a few cases. In the present study the epitestosterone level in human plasma was determined by a specific radioimmunoassay and the concentration of epitestosterone was established in age groups of males of 6 to 65 years of age. There is a clear age dependence of epitestosterone plasma concentration in males. In young boys before puberty, antiandrogenic epitestosterone prevails over testosterone, in adults a striking decline of the ratio epitestosterone:testosterone can be observed.
Publication
Journal: Journal of Clinical Endocrinology and Metabolism
February/2/2005
Abstract
Urinary steroid excretion after androstenedione intake has been examined after a single dose of 50 mg and single doses of 100 or 300 mg/d for 7 d. We evaluated the effects of 28 d of 100 mg three times a day (t.i.d.) androstenedione intake on urinary steroid excretion. Twenty healthy men, ages 30-39 yr (33.5 +/- 0.6), consumed 100 mg androstenedione t.i.d. or placebo for 28 d. Urine samples were analyzed for testosterone, epitestosterone, androsterone, and etiocholanolone via HPLC/tandem mass spectrometry on d 0 and 28. Androstenedione intake increased (P < 0.05) urinary testosterone 35.1 +/- 10.5 ng/ml vs. 251.6 +/- 87.5 ng/ml, epitestosterone 35.3 +/- 8.8 ng/ml vs. 99.7 +/- 28.7 ng/ml, androsterone 2,102 +/- 383 ng/ml vs. 15,767 +/- 3,358 ng/ml, and etiocholanolone 1,698 +/- 409 ng/ml vs. 11,329 +/- 2,656 ng/ml (means +/- se). Although the testosterone to epitestosterone ratio (T/E) tended to increase with androstenedione intake (1.2 +/- 0.3 vs. 4.0 +/- 1.6; P = 0.12), only one subject had a urinary T/E greater than the current Olympic criteria (>6.0) for a positive drug test. Chronic intake of 100 mg androstenedione t.i.d. increases the urinary excretion of steroid metabolites. Due to inconsistent increases in the T/E ratio, the T/E ratio may not effectively detect androstenedione use.
Publication
Journal: Endokrinologie
July/18/1974
Publication
Journal: Rapid Communications in Mass Spectrometry
February/18/2009
Abstract
Studies have shown that the administration of androstenedione (ADIONE) significantly increases the urinary ratio of testosterone glucuronide to epitestosterone glucuronide (T/E) - measured by gas chromatography/mass spectrometry (GC/MS) - in subjects with a normal ( approximately 1) or naturally high (>1) initial values. However, the urinary T/E ratio has been shown not to increase in subjects with naturally low (<1) initial values. Such cases then rely on the detection of C(6)-hydroxylated metabolites shown to be indicative of ADIONE administration. While these markers may be measured in the routine GC/MS steroid profile, their relatively low urinary excretion limits the use of gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS) to specifically confirm ADIONE administration based on depleted (13)C content. A mass spectrometry strategy was used in this study to identify metabolites of ADIONE with the potential to provide compound-specific detection. C(4)-hydroxylation was subsequently shown to be a major metabolic pathway following ADIONE administration, thereby resulting in urinary excretion of 4-hydroxyandrostenedione (4OH-ADIONE). Complementary analysis of 4OH-ADIONE by GC/MS and GC/C/IRMS was used to confirm ADIONE administration.
Publication
Journal: Journal of Chromatography A
August/12/2008
Abstract
The medical commission of the International Olympic Committee forbids the use of anabolic androgenic steroids to improve sporting performances. Nine anabolic steroids (androsterone (A), nandrolone, estradiol, testosterone propionate, nandrolone-17 propionate, dydrogesterone, testosterone, epitestosterone, boldenone) and alpha-cholestane as internal standard were studied by gas chromatography coupled with mass spectrometry (GC/MS). The derivatisation reagent employed for the derivatisation of anabolic steroids was a mixture of N-methyl-N-trimethylsilyltrifluoroacetamide (MSTFA), ammonium iodide and 2-mercaptoethanol (1000:2:6, v/w/v). Trimethylsilyl (TMS) derivatives were obtained. Anabolic steroids can be derivatised into one or two forms, mainly for androsterone into A-monoTMS and A-diTMS. The aim of this study was to research the optimization conditions of the derivatisation process (maximum yield of silylation reaction) of each anabolic steroid into only one form. A two-level factorial Doelhert design was used to determine the influence of different parameters and their interactions on each compound, thanks to response surface methodology. The parameters to be optimized were the reaction time and the temperature. The interaction "temperature-reaction time" is significant and has a positive effect on the improvement of the effectiveness of the derivatisation. Considering the large amount of information, often not convergent, a global desirability function was applied for multi-responses optimization. Thus, the optimized temperature and the reaction time of silylation were 85 degrees C and 24 min, respectively. Several GC/MS analytical parameters were also studied: linearity (regression coefficient upper than 0.99 for each compound, sensibility (range of concentration 0.05-0.30 microg/ml). Confirmatory experiments were applied to check the predicted values and to validate the model. The confirmatory assay responses are relatively close to the responses predicted. We observed satisfactory resolutions by GC/MS and a run lower than 12 min.
Publication
Journal: International journal of chronobiology
March/18/1974
Publication
Journal: Steroids
April/20/1967
Publication
Journal: Journal of Endocrinology
December/19/1979
Abstract
Epitestosterone, a product of the metabolism of androstenedione by the caprine placenta in vitro, is present in the plasma of the pregnant goat. The maternal concentrations of both epitestosterone and unconjugated oestrogens (mostly oestradiol-17 alpha) in the blood increased before parturition and dropped post partum. Measurement of arteriovenous differences at term indicated that epitestosterone was secreted by the uterus; its production was not dependent on the presence of corpora lutea. It is suggested that the concentration of epitestosterone (+ androstenedione + oestrogens) in maternal plasma may be used as an indicator of placental C-17,20 lyase activity; the slight rise in the concentration of these compounds prepartum suggests a relatively small increase in flow through this enzyme.
Publication
Journal: Journal of steroid biochemistry
February/19/1988
Abstract
A radioimmunoassay system for 17 alpha-hydroxy-4-androstene-3-one (epitestosterone) was developed and evaluated using rabbit antisera against 17 alpha-hydroxy-4-androstene-3-one-3-(O-carboxymethyl)-oxime-bovine serum albumin conjugate, and radioiodinated homologous histaminyl derivative of epitestosterone as a tracer. Two antisera with different specificity were used for radioimmunological determination of epitestosterone in hydrolyzed urine and plasma, respectively. Apparent intrinsic association constants and derived thermodynamic variables for ligand-antibody interaction were measured under various conditions in order to set up an optimal assay protocol. The mean plasma epitestosterone levels for healthy subjects were 0.44 +/- 0.15 nmol.l-1 (means +/- SD) in males and 0.092 +/- 0.056 nmol.l-1 in females. The corresponding concentrations in urine were 320 +/- 70 nmol.l-1 (males) and 273 +/- 100 nmol.l-1 (females).
Publication
Journal: Journal of reproductive medicine, The
September/28/1978
Abstract
Fourteen patients with clinically diagnosed and surgically documented polycystic ovarian (Stein-Leventhal) disease (PCOD) and 16 normal control women were studied to identify the laboratory test or tests that, from the clinician's point of view, are most likely to aid in the nonsurgical diagnosis of the disease. A single random morning blood specimen was assayed in all cases for testosterone, epitestosterone, androstenedione, FSH and LH. The mean testosterone level for the PCOD patients was significantly greater (p less than 0.001) than that for the controls, with 50% of the patients showing elevated levels. Androstenedione showed a similar pattern, but mean epitestosterone levels were not significantly different from controls. FSH was not significantly different, but LH levels were significantly higher than controls (p less than 0.005), with 10 of 13 (77%) demonstrating elevated levels. A strong positive correlation was also found between the degree of virilization and the levels of LH, testosterone and androstenedione. This study suggests that the most useful diagnostic laboratory assay from a single drawing of blood is the serum LH; the only other useful test is testosterone and/or androstenedione. These data do not support other reports of elevated levels of epitestosterone or decreased values of FSH in PCOD.
Publication
Journal: Blood
July/5/1976
Abstract
A double isotope ratio technique was used to estimate the specific binding of testosterone (T), as opposed to its biologically nonactive stereoisomer, epitestosterone (Epi T). The mouse erythropoietic spleen formed in response to a phenylhydrazine-induced hemolytic anemia was used as the target organ. Spleen minces from preanemic mice, as well as those in the early and late phases of erythropoietic spleen development, were incubated with 10(-9) M of 14C-T and 3H-EpiT, and the selective uptake of T was calculated from the 14C/3H ratio measured in the media before and after incubation, as well as in the subcellular fractions of the minces. Preferential uptake of T was seen in the early phase of development, but not in spleens obtained from preanemic animals or those in the late phase. There was no evidence of metabolic conversion of T or EpiT. The selective uptake of T by early phase spleens was reflected in a preferential nuclear accumulation of T. These data represent the first demonstration of a specific binding of T in vitro to a developing erythroid tissue.
Publication
Journal: British Journal of Sports Medicine
January/29/1992
Abstract
Human chorionic gonadotrophin (hCG) is a glycoprotein hormone which is produced in large amounts during pregnancy and also by certain types of tumour. The biological action of hCG is identical to that of luteinizing hormone, although the former has a much longer plasma half-life. Some male athletes use pharmaceutical preparations of hCG to stimulate testosterone production before competition and/or to prevent testicular shutdown and atrophy during and after prolonged courses of androgen administration. Testosterone administration can be detected by measuring the ratio of concentrations of testosterone to epitestosterone (T/E). An athlete is often considered to have failed a drug test if the urinary T/E ratio is greater than 6. In contrast, hCG administration stimulates the endogenous production of both testosterone and epitestosterone without increasing the urinary T/E ratio above normal values. Although the administration of hCG was banned by the International Olympic Committee (IOC) in 1987, no definitive test for hCG has been approved by the IOC. Currently, the only way of measuring small concentrations of hCG is by immunoassay, and this does not have a discriminating power as great as gas-liquid chromatography with mass-spectrometry which is necessary to satisfy IOC requirements. Extraction procedures and chromatographic steps could be introduced before using a selected immunoassay for hCG to meet these requirements.
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Publication
Journal: European journal of clinical chemistry and clinical biochemistry : journal of the Forum of European Clinical Chemistry Societies
September/21/1997
Abstract
Epitestosterone, a C19-steroid with anti-androgenic activity, was determined in the plasma of 234 boys and men from the ages of 6-86 years, and in the prostate tissue of 15 men 55-82 years of age. It was documented that, while in adulthood the concentration of epitestosterone is about ten times lower than the concentration of testosterone, in the pre-pubertal period the level of epitestosterone is similar or even higher than that of testosterone. In the hyperplastic prostate tissue the content of epitestosterone is comparable to that of androstenedione, it is about twice as high as the content of testosterone and approximately half that of the content of dihydrotestosterone. At least in the case of pre-pubertal boys and in the prostatic tissue it is therefore possible to include epitestosterone into consideration as a regulatory factor for the androgen-dependent events.
Publication
Journal: Journal of Biological Chemistry
August/31/1976
Abstract
The metabolism and binding of [1, 2, 6, 7-3H] testosterone in male and female rat brain has been studied in an attempt to find an explanation for the relative androgen unresponsiveness characterizing the female hypothalamo-pituitary axis involved in regulation of hepatic steroid metabolism. The most significant sex differences in the pattern of [3H] testosterone metabolites recovered from several brain regions (including pituitary, pineal gland, and hypothalamus) after intraperitoneal administration of [3H] testosterone were the predominance of testosterone and androstenedione in male brain compared to the quantitative importance of 5alpha-androstane-3alpha, 17beta-diol, 5alpha-androstane-3beta, 17beta-diol, epitestosterone, and dihydroepitestosterone in female brain. One possible explanation for the androgen unresponsiveness of female rats is, therefore, the faster metabolism of testosterone to inactive compounds in female brain. Experiments both in vivo and in vitro showed the presence of high affinity, low capacity binding sites for [3H] testosterone in male pituitary, pineal gland, and hypothalamus (Kd values in the region of 1 X 10(-10) to 1 X 10(-9) M and number of binding sites 1.0 to 1.4 X 10(-14) mol per mg of protein). The steroid - macromolecular complexes generally had a pI of 5.1, were excluded from Sephadex G-200, were heat-labile, and were sensitive to protease. Competition experiments indicated the following order of ligand affinities: testosterone is greater than 5alpha-dihydrotestosterone and estradiol is greater than androstenedione is greater than corticosterone. No steroid-binding proteins of similar nature were found in pituitary, pineal gland, or hypothalamus from female rats. On the basis of these results it is suggested that the androgen unresponsiveness of female rats referred to above relates to the absence of receptor protein for androgens in female rat brain. In support of this hypothesis, 28-day-old female rats, which are known to be affected by androgens with regard to liver enzyme activities, were shown to contain receptor proteins for androgen in the brain. In conclusion, the relative androgen unresponsiveness of the female hypothalamo-pituitary axis is probably explained by the absence of receptor proteins for androgen in female hypothalamus and pituitary. The fast metabolism of testosterone in female rat brain also serves to decrease the availability of active androgen to potential receptor sites. It may be speculated that the presence of androgen receptors in male brain is the result of neonatal programming ("imprinting") by testicular androgen.
Publication
Journal: Journal of Pharmaceutical and Biomedical Analysis
January/29/2012
Abstract
Manipulation of urine specimens provided by elite athletes for doping control purposes has been reported several times in the past, and in most of these cases urine substitution was eventually proven. Recent findings of suspected and substantiated manipulation have outlined the complexity and diversity of tampering options, sample appearance alterations resulting from non-manipulative influence, and the analytical challenges arising from these scenarios. Using state-of-the-art mass spectrometric and immunological doping control and forensic chemistry methodologies, four unusual findings were observed. One sports drug testing specimen was found to contain an unusually high content of saccharides accompanied by hordenine and Serpine-Z4, while no endogenous steroid (e.g. testosterone, epitestosterone, androsterone and etiocholanolone) was detected. This specimen was identified as non-alcoholic beer filled into the doping control sample container, constituting an undisputed doping offense. A doping control sample of bright green color was received and found to contain residues of methylene blue, which is not considered relevant for doping controls as no masking or manipulative effect is known. In addition, the number of urine samples of raspberry to crimson red coloration received at doping control laboratories has constantly increased during the last years, attributed to the presence of hemoglobin or betanin/isobetanin. Also here, no doping rule violation was given and an impact on routine analytical results was not observed. Finally, a total of 8 sports drug testing samples collected at different competition sites was shown to contain identical urine specimens as indicated by steroid profile analysis and conclusively proven by DNA-STR (short tandem repeat) analysis. Here, the athletes in question were not involved in the urine substitution act but the doping control officer was convicted of sample manipulation.
Publication
Journal: Handbook of Experimental Pharmacology
February/25/2010
Abstract
The list of prohibited substances in sports includes a group of masking agents that are forbidden in both in- and out-of-competition doping tests. This group consists of a series of compounds that are misused in sports to mask the administration of other doping agents, and includes: diuretics, used to reduce the concentration in urine of other doping agents either by increasing the urine volume or by reducing the excretion of basic doping agents by increasing the urinary pH; probenecid, used to reduce the concentration in urine of acidic compounds, such as glucuronoconjugates of some doping agents; 5alpha-reductase inhibitors, used to reduce the formation of 5alpha-reduced metabolites of anabolic androgenic steroids; plasma expanders, used to maintain the plasma volume after misuse of erythropoietin or red blood cells concentrates; and epitestosterone, used to mask the detection of the administration of testosterone. Diuretics may be also misused to achieve acute weight loss before competition in sports with weight categories. In this chapter, pharmacological modes of action, intended pharmacological effects for doping purposes, main routes of biotransformation and analytical procedures used for anti-doping controls to screen and confirm these substances will be reviewed and discussed.
Publication
Journal: Drug Testing and Analysis
May/3/2012
Abstract
In the present study, the content of a number of black market testosterone products collected in Austria has been analyzed. Additionally, (13) C/(12) C ratios were measured for testosterone in the products after cleavage of the testosterone ester. The aim was to determine whether some of these products had similar (13) C/(12) C ratios to those normally found for endogenous testosterone, which could prevent a positive isotopic ratio mass spectrometric (IRMS) finding in doping control. Moreover, it was investigated to what extent the preparations contained the masking agent epitestosterone, in order to lower the testosterone/epitestosterone (T/E) ratio in urinary steroid profiles. Out of 30 analyzed products, the declared ingredients differed from the actual content in 10 cases. Epitestosterone, however, could not be found in any of the products. The products displayed δ(13)C(VPDB) values between -23.6 and -29.4‰. For more than half of these products, the values were within a range reported for endogenous urinary steroids.
Publication
Journal: Journal of Analytical Toxicology
April/29/2002
Abstract
Dehydroepiandrosterone (DHEA) and androstenedione are weak androgens, which need conversion to more potent testosterone in order to enhance anabolic action. Consequences of oral dosing at 1 mg/kg on the urinary and plasma androgen profile of mare and gelding have been evaluated with an analytical method involving conjugate fractionation and selective hydrolysis, group separation, and quantitation by gas chromatography-mass spectrometry with selected ion monitoring of trimethylsilyl ethers. Peak levels of testosterone total conjugates in urine (range 300-6000 microg/L) were attained a few hours after dosing. Renal clearance was fast, so the testosterone detection period lasted only 20 to 33 h, the longest time being generated by androstenedione. The urinary testosterone/epitestosterone ratio for detection of exogenous testosterone in the mare was inoperative after DHEA administration because there was a concomitant increase of epitestosterone, which thereby acted as a masking agent. Androstanediols and androstenediols, as well as some 17-ketosteroids, were additional markers. A transient increase of circulating free testosterone has been evidenced, and this would support possible anabolic/androgenic action by supplementation with DHEA and androstenedione along the oral route.
Publication
Journal: Prostate
October/31/1984
Abstract
Canine prostatic epithelial cells were cultured in primary monolayers in order to define those factors that induce a proliferative response at the cellular level. Cultures were performed in a serum-free medium or in a medium supplemented either with fetal bovine serum or dog serum in the presence or absence of several sex steroids (androstenedione, testosterone, dihydrotestosterone, 3 alpha- and 3 beta-androstanediols, epitestosterone, epidihydrotestosterone, estrone, estradiol, and progesterone). Cell proliferation was observed in the absence of serum and exogenous steroids. The rate of cell division was serum dependent and steroid independent. Pretreatment of sera with charcoal had no effect on their mitogenic activities. Cells maintained in an endocrine milieu prior to tissue dispersion and throughout the whole procedure proliferate to the same extent as those deprived of hormones, whether free of serum or added supplements. The addition of insulin (2 micrograms/ml), dog prolactin (up to 25 ng/ml) and zinc (10(-8) to 10(-2) M) in a serum-free medium did not induce cell responsiveness to steroids. Dihydrotestosterone, 3 alpha-androstanediol, and estradiol alone or in combinations known to induce the growth of the canine prostate in vivo were ineffective in vitro. The proliferative responses to sera were time and concentration dependent, and dog serum was more potent than fetal bovine serum. Thus, humoral factors other than steroids, prolactin, insulin, or zinc may be of importance in the activation of epithelial cells involved in the development of prostatic hyperplasia and adenocarcinoma.
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