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PubMed1989

Effects of chronic LHRH-a + 17-methyltestosterone or LHRH-a + testosterone therapy on oocyte growth in the striped mullet (Mugil cephalus).

The striped mullet (Mugil cephalus) exhibits a restricted spawning season and matures only once per spawning cycle. In vivo monitoring of ovarian maturation of individual females during the season reveals that timing of full maturity varies. A small percentage of females that mature early can be induced to spawn and will remature. Such females can be spawned a second time within the same season. Chronic administration of luteinizing hormone-releasing analog (LHRH-a) + testosterone results in accelerated egg growth. The majority of females undergoing this therapy mature at least a month before control fish. When these females are induced to spawn, a higher percentage remature and can be spawned again. The double spawnings of both control and LHRH-a + testosterone-treated females occur without any appreciable loss in egg quality. Administration of LHRH-a + 17 alpha-methyltestosterone essentially inhibits egg growth. Steroid profiles from females undergoing this therapy exhibit a significant drop in circulating testosterone and estradiol 17 beta, compared to control and LHRH-a + testosterone-treated females. Hypotheses for the poor performance of this therapy are discussed.

Animals↗
PubMed1979

Selective catalytic reduction of 7-methyl-6-dehydrotestosterone acetate to 7 beta-methyltestosterone acetate by benzyl alcohol.

Using benzyl alcohol as a hydrogen donor in the presence of Pd on charcoal, 7-methyl-6-dehydrotestosterone acetate was selectively reduced to 7 beta-methyltestosterone acetate in 90% yield. The addition of hydrogen atoms to the 6, 7 double bond proceeded from the less hindered alpha-face of the steroid molecule, giving rise to the 7 beta-methyl product. Gas chromatograph analysis indicated small amounts of the 7 alpha-methyl epimer, 7 beta-methyl-5 alpha-dihydrotestosterone acetate and the 5 beta-epimer. The 6,7 double bond was hydrogenated in preference to 4,5 double bond, although both are trisubstituted.

Benzyl Alcohols↗
PubMed1991

The effect of methyltestosterone on the growth hormone response to the dopamine receptor agonist, apomorphine.

1. There is some evidence that androgens affect dopaminergic function in animals and man. We investigated the effect of methyltestosterone (MT) (30 mg po) on the growth hormone (GH) response to the dopamine (DA) receptor agonist, apomorphine (Apo) HC1 (0.5 mg sc), in 9 normal men. MT was given 2 hr before Apo. 2. The peak plasma MT concentration was present 1 hr after administration (19.9 +/- 19.5 ng/ml; X +/- SD); the concentration at 4 hr was 7.2 +/- 4.9 ng/ml. At the time of Apo administration, plasma MT varied from 6.0-24.1 ng/ml. 3. There was no significant effect of MT on Apo-GH secretion (interaction F(7,56) = 1.08; p = NS). The mean individual peak GH concentration after Apo alone was 20.2 +/- 11.9 (X +/- SD) vs 22.2 +/- 9.9 ng/ml when MT preceded Apo (p = NS). 4. These results suggest that exogenous androgens do not affect DA receptor function in males with normal androgenic function. Lack of effect due to an insufficient dose or duration of administration of MT cannot be excluded.

Adolescent↗
PubMed1995

Direct effects of the anabolic/androgenic steroids, stanozolol and 17 alpha-methyltestosterone, on benzodiazepine binding to the. gamma-aminobutyric acid(a) receptor.

Various exogenous and endogenous steroids have been demonstrated to have both enhancing and inhibiting effects on ligand binding to the gamma-aminobutyric acid(A) receptor (GABAA receptor) in previous studies. In the present study we have explored the possibility that an additional class of synthetic steroidal compounds, anabolic/androgenic steroids (AAS), mediate some of their CNS effects through direct interaction with the GABAa receptor. At micromolar concentrations, two AAS, stanozolol and 17 alpha-methyltestosterone (17 alpha-MT), significantly inhibited 1 nM [3H]flunitrazepam ([3H]Fln) binding to rat brain cerebrocortical membranes. Inhibition of 1 nM [3H]Fln binding by stanozolol was similar for both males and females (approximately 50% inhibition at 50 microM stanozolol). 17 alpha-MT was much less efficacious, but did significantly inhibit 1 nM [3H]Fln binding at concentrations > 10 microM. In equilibrium binding assays, stanozolol (50 microM) raised the apparent KD for [3H]Fln binding. The observed changes in the [3H]Fln binding curve, when analyzed by Rosenthal analysis, reveal complex equilibrium binding behavior. In females, the Rosenthal plot was best fit by a two site binding model. Stanozolol (50 microM) inhibited binding to the higher affinity site in a manner consistent with competitive inhibition, increasing the KD without changing the BMAX. However, the effect of stanozolol on the binding to the low affinity site was more complex, with an increase in the the KD and the BMAX. In males the data were best fit by a single binding site model. This single site exhibited a slight increase in the KD and a decrease in the BMAX in the presence of 50 microM stanozolol.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Combined high-performance liquid chromatography and radioimmunoassay for the screening of 19-nortestosterone and methyltestosterone residues in meat samples.

A procedure is described for the detection of 17 beta-19-nortestosterone (17 beta-19-NT) and 17 alpha-methyltestosterone (17 alpha-MT) in muscle tissue by a combination of high-performance liquid chromatography and radioimmunoassay. The steroids were released from the muscle tissue by enzyme digestion, and the extracts were purified by solid-phase extraction. A meat sample from the retail trade, which was proved to contain 17 beta-19-NT and 17 alpha-MT residues by gas chromatography-mass spectrometry, and blank meat samples obtained from non-treated experimental animals were purified and the extracts injected into the liquid chromatograph. With an automatic fraction collector, fifteen fractions of 1 ml each were obtained, which after evaporation were subjected to a radioimmunoassay for the steroid concerned. It was demonstrated that none of the fractions from the blank meat samples contains any substance that interfered with the immunochemical detection system. In addition, a good qualitative agreement between the two sets of results was obtained. Although the sample preparation step is rather labour-intensive, the method can be successfully applied as a reliable confirmation method for positive radioimmunoassay screening results in circumstances where no gas chromatography-mass spectrometry facilities are available.

Animals↗
PubMed1991

Use of an immobilized enzyme reactor for the analysis of residues of 17 alpha-methyltestosterone in trout by high-performance liquid chromatography.

We have recently observed in trout that 48 h after ingestion of a single dose of [14C]-17 alpha-methyltestosterone ([14C]-MT), 25% of the radioactivity was still in the carcass, corresponding to metabolites of 17-MT. These compounds have no appreciable chromophore, fluorophore or electrophore, therefore the usual detection systems was not satisfactory for their analysis. Consequently a method was developed for high-performance liquid chromatographic separation and detection of two of the major tissue metabolites of 17-MT: 5 alpha-androstane-17 alpha-methyl-3 alpha,17 beta-diol and 5 beta-androstane-17 alpha-methyl-3 alpha,17 beta-diol. A column of immobilized 3 alpha-hydroxysteroid dehydrogenase was prepared and used for detection. The NADH produced from 3-hydroxysteroids by this immobilized enzyme reactor was monitored fluorimetrically. The detection limit of this method, as obtained from the calibration curve, was at the picomole level; the limit of quantification in muscle was 1 microgram/kg, at a signal-to-noise ratio of 4.

Animals↗
PubMed1996

Gas chromatography/mass spectometry identification of long-term excreted metabolites of the anabolic steroid 4-chloro-1,2-dehydro-17alpha-methyltestosterone in humans.

The misuse of anabolic steroids by athletes has been banned by sports organizations and is controlled by the analysis of urine samples obtained from athletes using gas chromatography/mass spectrometry (GC/MS). To extend the retrospectivity of the analytical methods, research is focused on long-term excreted metabolites. Preliminary results concerning the long-term detection of metabolites of the anabolic androgenic steroid 4-chloro-1,2-dehydro-17alpha-methyltestosterone I are presented. A new metabolite 4-chloro-3alpha, 6 beta, 17beta-trihydroxy-17alpha-methyl-5beta-androst-l-en-16-one was isolated by high performance liquid chromatography (HPLC) from urine following a single oral administration of 40 mg of I and characterized. Metabolite II was excreted into urine with a maximum excretion rate at approximately 48 h after administration and could be detected by gas chromatography/high resolution mass spectrometry (GC/HRMS) for up to 14 days. Two further partly characterized metabolites III and IV were confirmed for more than 9 days. The same three metabolites, II-IV, in varying amounts were also detected in urine samples from athletes who administered I.

Adult↗
PubMed2005

Combined esterified estrogen and methyltestosterone treatment for dry eye syndrome in postmenopausal women.

PURPOSE: To determine whether systemic replacement with combined esterified estrogen (EE) and methyltestosterone (MT) (EE + MT) would reduce symptoms and promote clinical improvement in postmenopausal women with dry eye syndrome (DES). DESIGN: Retrospective, noncomparative, interventional case series. METHODS: Investigators reviewed the charts of 11 postmenopausal women treated within the last 3 years with EE + MT. RESULTS: The mean patient age was 65.2 years (standard deviation [SD] 11.4, range 48-84 years). The mean treatment duration was 12.2 months (SD 6.2 months, range 4-24 months). Ten (91%) of 11 patients reported improvement in dry eye symptoms while receiving treatment. For these 10, relief occurred after an average of 4.1 months of treatment (SD 3.2, range, 1-9 months). CONCLUSIONS: Treatment with EE + MT may be efficacious for DES of various etiologies. A randomized placebo-controlled trial is planned to further evaluate these encouraging findings.

Aged↗
PubMed2005

Short-term exposure to low concentrations of the synthetic androgen methyltestosterone affects vitellogenin and steroid levels in adult male zebrafish (Danio rerio).

Short-term effects of methyltestosterone (MT) on the endocrine system of adult male zebrafish (Danio rerio) were examined. Males were exposed to 0, 4.5, 6.6, 8.5, 19.8, 35.9, 62.3 ng MT/l and ethinylestradiol (EE2) (26.4 ng/l) for 7 days. Several physiological endpoints that may be affected by endocrine disrupters were analysed, specifically vitellogenin (VTG) concentration, estradiol (E2), testosterone (T), and 11-ketotestosterone (KT) content, brain aromatase activity and gene expression of CYP19A1 and CYP19A2 in the testis. Exposure to the lowest MT concentration (4.5 ng MT/l), and the EE2 increased the concentration of VTG significantly compared to solvent control group. Exposure to higher concentrations of MT did not increase VTG levels. Endogenous KT and T levels decreased significantly in a concentration-dependent manner in response to the MT exposure and the lowest effective concentrations were 6.4 and 8.5 ng MT/l, respectively. The levels of KT and T were also significantly suppressed by EE2 when compared to the solvent control group. Significant decreases in endogenous E2 levels were found in some MT groups but it was not possible to distinguish a simple concentration-response relationship. No effects of MT or EE2 on the brain aromatase activity or on testicular gene expression of CYP19A1 and CYP19A2 were detected. The results show that androgens such as MT can act as endocrine disrupters even at very low concentrations.

Analysis of Variance↗
PubMed2004

A combined regimen of gossypol plus methyltestosterone and ethinylestradiol as a contraceptive induces germ cell apoptosis and expression of its related genes in rats.

Attempts to develop gossypol and steroidal hormones alone as a male contraceptive have been tested for many years; however, both caused undesirable side effects that have prevented their acceptance. In this study, we formulated a regimen of combined gossypol at a low dose of 12 mg/kg or a high dose of 50 mg/kg plus methyltestosterone 20 mg/kg and ethinylestradiol 100 g/kg daily (12 mg G+H and 50 mg G+H) administered for 6 weeks in adult rats. The possible roles of germ cell apoptosis and related genes expression were studied by techniques of TdT-mediated dUTP nick end-labeling (TUNEL), agarose gel electrophoresis of low-molecular-weight DNA, in situ hybridization and reverse transcription-polymerase chain reaction detection. Results showed that germ cell apoptosis and related genes expression were significantly induced after combined drug administration. The apoptosis index increased 3.86- and 9.65-fold in the 12-mg and 50-mg G+H-treated groups, respectively, as compared to the control group. DNA ladder formation on the agarose gel further validated the findings of TUNEL-stained apoptotic cells. The apoptosis-related genes fas mRNA expression levels increased 0.44- and 1.39-fold, bax mRNA 0.74- and 2.56-fold, caspase-3 mRNA 0.60- and 1.29-fold, and caspase-9 mRNA 2.50- and 4.08-fold, respectively, in the 12-mg and 50-mg G+H-treated groups vs. the control group. These results indicated that our drug regimen applied as a contraceptive could induce rat germ cell apoptosis. The apoptotic process involved fas system, bax and caspase family genes and the apoptotic extent and cell types were gossypol dose-dependent.

Animals↗
PubMed2005

Effects of methyltestosterone on reproduction in the Japanese quail (Coturnix coturnix japonica).

Although the hormone-mediated effects of the synthetic androgenic hormone methyltestosterone (MT) are well characterized in mammals, little is known about endocrine and other toxic effects on reproduction in birds. In a one-generation study, MT was administered to adult Japanese quail (12 pairs per group) at dietary dose levels of 0, 10, 50, and 110 ppm for a period of 3 weeks. Reproductive performance was severely affected in the groups receiving 50 and 110 ppm MT. In females, the egg-laying rate was reduced not only related to the dose administered but also to the duration of treatment. The administration of 110 ppm, and to a lesser extent, of 50 ppm MT resulted in an immediate and dramatic decrease in the total number of eggs laid, which complicated reliable assessment of other reproduction-related parameters. In males, the findings suggested inhibition of spermatogenesis at dose levels of 50 ppm and above, resulting in a subsequent reduction in male fertility.

Anabolic Agents↗
PubMed2006

Effects of the model androgen methyltestosterone on vitellogenin in male and female eelpout, Zoarces viviparus (L).

In the present experiment male and female eelpout, Zoarces viviparus were exposed to different doses of the model androgen 17alpha-methyltestosterone (MT) and the effects on the plasma level of vitellogenin and the gonadosomatic index were investigated. In females exposed to different doses of MT (nominal concentrations 10, 25, 50, 100 and 500 ng/L) in the ambient seawater, the concentrations of the circulating yolk-precursor protein vitellogenin (vtg) were shown to decrease in all groups but only significantly in the MT-100 group when compared to controls. No significant effects could be observed on the GSI during early vitellogenesis (April/May). Males exposed to E2 under flow through conditions during 10 days showed an induced synthesis of vtg as depicted by a high level of circulating vtg. When the estrogen-exposed males were subsequently exposed to different doses of MT only, during another 10 days, the levels of vtg decreased significantly in three of the MT-treated groups when compared with the level of vtg in plasma of the estrogen-treated group after the first 10 days. The gonadosomatic index was observed to decrease by the estradiol-treatment but to increase in a dose-dependent manner in the MT-exposed groups, indicating that MT had the capacity to override the effect of the preceding exposure to estradiol-17beta.

Animals↗
PubMed2006

Central effects of the anabolic steroid 17alpha methyltestosterone in female anxiety.

The androgen 17alpha-methyltestosterone (17alpha-meT) is one of the most commonly abused anabolic androgenic steroids (AAS). We assessed the impact of 17alpha-meT after bilateral infusion into the dorsomedial hypothalamus (DMH) in female anxiety. A paradoxical effect in Vogel conflict test (VCT) behavior was noted: while AAS infusion induced an increase in the latency to display the appetitive reaction of the task, it also increased the number of punished responses. No changes in elevated plus maze (EPM) behavior were noted. However, AAS infusion induced an increase in social interactions. Changes in social interactions were mimicked by muscimol infusion and counteracted by co-infusion of AAS plus the GABAA receptor (GABAA-R) antagonist GABAzine. A reduction of systolic blood pressure was registered after AAS infusion in the DMH. No changes in fluid intake or locomotor behaviors were noted. We conclude that the AAS 17alpha-meT modulates distinct anxiety domains in females through a fast-acting mechanism.

Animals↗
PubMed2005

Modulation of elevated plus maze behavior after chronic exposure to the anabolic steroid 17alpha-methyltestosterone in adult mice.

Exposure to supraphysiological doses of androgens may disrupt affective components of behavior. In this study, behavior of adult C57Bl/6 male mice was studied after exposure to the anabolic androgenic steroid (AAS) 17alpha-methyltestosterone (17alpha-meT; 7.5 mg/kg) via a subcutaneous osmotic pump for 17 days. Controls received vehicle implants (0.9% NaCl + 30% cyclodextrine). On day 15, experimental animals were challenged with an ethanol (EtOH) injection (i.p.; 1 g/kg) while controls received saline injections. Five minutes after the injection, animals were tested in an automated elevated plus maze (EPM) or in automated activity chambers. In addition, injection-free animals were tested for ethanol consumption on day 16 after an overnight water deprivation period. Whereas chronic exposure to 17alpha-meT did not modulate open arm behavior, EtOH-exposed animals made more entries into the open arms than controls (P < 0.05). A significant reduction of risk assessment behaviors (rearing, flat approach behavior, and stretch attended posture) over the EPM was noted for EtOH-exposed animals whereas a reduction in stretch attended postures was observed among 17alpha-meT-exposed animals. Locomotor activity, and light-dark transitions in activity chambers remained unaltered. Exposure to AAS did not modulate EtOH consumption. Our data suggest that exposure to a supraphysiological dose of 17alpha-meT has minimal effects on exploratory-based anxiety.

Alcohol Drinking↗
PubMed1980

The combined use of oral medroxyprogesterone acetate and methyltestosterone in a male contraceptive trial programme.

A male contraceptive trial was undertaken in 23 men using a combination of oral medroxyprogesterone acetate (MPA) and oral methyltestosterone (MeT). The men were divided into four groups according to varying drug dosages and were followed for 15 months (control - 3 months, treatment - 6 months, follow-up - 6 months). The parameters assessed included sperm count and motility, serum gonadotropins and sex steroids, and several biochemical and hematological tests. A questionnaire dealing with side-effects and changes in sexual function was administered intermittently. Although sperm count was suppressed (most dramatically at the highest drug doses, MPA 20mg,MeT 20mg), it was not suppressed to infertile levels. Sperm motility was unaltered; LH was modestly suppressed, FSH was not suppressed; testosterone was suppressed even at low doses; dihydrotestosterone responses were inconsistent. No significant biochemical abnormalities or side-effects occurred although some men experienced mild transient acne, gynecomastia and decreased testicular size. We conclude that in the doses used in this trial, the combination of MPA and MeT is not effective for male contraceptive, purposes and that higher doses may induce severe and undesirable side-effects.

Clinical Trials as Topic↗
PubMed2002

Increased 21-hydroxylase and shutdown of C(17,20) lyase activities in testicular tissues of the grouper (Epinephelus coioides) during 17alpha-methyltestosterone-induced sex inversion.

The metabolism in vitro of [(3)H]17-hydroxyprogesterone by gonadal tissues of the grouper (Epinephelus coioides) during 17alpha-methyltestosterone (MT)-induced female-to-male sex inversion was examined. In the female phase, C(17,20) lyase, 5beta-reductase, 3alpha/beta-HSD, 20beta-HSD, and 17beta-HSD activities resulted in the biosynthesis of 5beta-pregnans and 5beta-androstanes (including 5beta-androstane-3alpha/beta, 17beta-diol, 3alpha/beta, 17alpha-dihydroxy-5beta-pregnen-20-one, and 5beta-androstane-3,17-dione). In the MT-induced male phase, however, the abrogation of C(17,20) lyase activity and the concomitant activation of 21alpha-hydroxylase/11beta-hydroxylase resulted in the preferential synthesis of polar 21alpha-hydroxlyated 5beta-pregnans (5beta-pregnan-3beta,17alpha,20beta,21alpha-tetrol and 3beta,20beta,21alpha-trihydroxy-5beta-pregnan-3-one) and corticosteroids (11-deoxycortisol and cortisol). Interestingly, synthesis of these 21alpha-hydroxylated 5beta-pregnans and corticosteroids was uniquely compartmentalized in only testicular tissues of the MT-induced males. This study shows that there is selective activation of specific steroidogenic enzymes in the different sexual phases leading to the synthesis of metabolites that may be involved in regulating sex inversion of the grouper.

17-alpha-Hydroxyprogesterone↗
PubMed2002

Activation of the growth hormone/insulin-like growth factor axis by treatment with 17 alpha-methyltestosterone and seawater rearing in the tilapia, Oreochromis mossambicus.

Effects of 17 alpha-methyltestosterone (MT) treatment and environmental salinity on the growth hormone (GH)/insulin-like growth factor (IGF) axis were examined in the euryhaline tilapia, Oreochromis mossambicus. Yolk-sac fry were collected from brood stock in fresh water (FW). After yolk-sac absorption, they were assigned randomly to 1 of 4 groups: FW, MT treatment in FW, SW, and MT treatment in seawater (SW). After 147 days, FW controls had the lowest levels of GH mRNA followed by FW fish treated with MT and SW control fish. Seawater fish fed with a diet containing MT, which grew the fastest, had significantly higher levels of GH mRNA than all the other groups. A significant correlation was observed between GH mRNA and the size of the individual fish. By contrast, plasma GH levels did not vary significantly among the groups. Pituitary GH mRNA levels, plasma IGF-I levels, and fish size varied in a correlated pattern, i.e., SW+MT>FW+MT=SW control>FW control. The tilapia pituitary produces two prolactins (PRLs), PRL(177) and PRL(188). Prolactin(177), but not PRL(188), exhibits growth-promoting actions in FW tilapia. Pituitary mRNA levels of both PRLs were significantly higher in fish reared in FW than those reared in SW. Treatment with MT significantly increased mRNA levels of both PRLs in FW, but had no effect on SW fish. No correlation was seen between plasma PRL levels and growth or between PRL mRNA levels and growth. These results indicate that SW rearing and MT treatment stimulate the GH/IGF-I axis, and suggest that pituitary GH mRNA at this stage of development is a better indicator of growth than plasma levels of GH and IGF-I.

Animals↗
PubMed1999

The effects of oral administration with 17 alpha-methyltestosterone on chromosomal synapsis in Oreochromis niloticus (Pisces, Cichlidae).

The pattern of chromosomal synapsis after treatment with 17 alpha-methyltestosterone (MT), a testosterone analogue routinely used for the reversal of phenotypic sex in aquaculture, was investigated using the Nile tilapia (Oreochromis niloticus) as a model teleost species. Progeny-tested, monosex diploid (2n = 44) individuals were orally administered with diets containing 50 mg/kg MT for 30 days after first feeding (XX(MT) neomales and XY(MT) males) and compared to controls (XY males). The formation and structure of the synaptonemal complex (SC) and the nature of chromosomal synapsis were investigated in control and treated groups by computer-assisted image analysis of transmission electron microscope (TEM) microphotographs taken from SC spreads. Nuclei at the pachytene stage were first observed in XX(MT) neomales, indicating an earlier commitment of genetically female spermatocytes to enter the first meiotic prophase. Administration of MT did not result in obvious SC lesions, breakage, asynapsis or formation of multivalents in genotypic females (XX(MT) neomales). Administration of MT resulted in a significant increase in the SC lengths in XY(MT) males, although it did not significantly alter the pattern of synapsis (SC structure and number and morphology of bivalents) in comparison to XY controls. The significance of the effects and the putative mode(s) of action of MT on chromosomal synapsis in teleosts is discussed.

Administration, Oral↗