Methyltestosterone Research Articles

The effect of feeding three anabolic steroids in different combinations on the growth, food conversion efficiency and protein and nucleic acid levels of liver, kidney, brain and muscle of mirror carp (Cyprinus carpio)

A study on the effect of three different anabolic-androgenic steroids on the growth, food conversion efficiency and nucleic acid contents of liver, kidney, brain and muscle of carp,Cyprinus carpio was undertaken. The three steroids, methyltestosterone (MT), ethylestrenol (EE) and oxandrolone (ON), were fed in different combinations at final concentrations of 5 or 6 mg/kg diet for 60 days. No effect on the growth was observed in any of the experimental groups. A decrease in the specific growth rate (11-21%) and food conversion efficiency (20-29%) was noted. Feeding of drugs increased the cranio-somatic and reno-somatic index in all except one group. Hepatosomatic (ON+MT) and viscero-somatic (ON+MT; EE+MT+ON) indices decreased. Protein increased and RNA/DNA decreased in only one group while a decrease in protein/DNA was observed in the liver of all experimental groups. RNA/DNA increased and protein/RNA decreased only in one group while no effect was seen in protein and protein/DNA contents in any of the treated kidneys. Proteins, protein/RNA and protein/DNA decreased in certain groups in brain tissue. In muscle, no effect was seen in proteins or protein/DNA. Protein/RNA decreased in all but one group while RNA/DNA was higher only in the group fed all the three steroids together.

Chemiluminescence immunoassay for the detection and quantification of methylestosterone residues in muscle tissue

Chemiluminescence as a detection method for immunoassays has succesfully been applied to the measurement of methyltestosterone (MT) residues in muscle tissue. The sample is digested enzymatically, extracted with diethyl ether and purified on a Lipidex-5000 column. An optional clean-up utilized disposable C 18 columns. As the luminescent label the N-(4-aminobutyl)-N-ethylisoluminol conjugate of MT was used. The antiserum was raised in a rabbit against MT-3-carboxymethyloximebovine serum albumin. The detection limit of the assay was 14 ± 7 pg ( n = 13), with a limit of quantification in muscle tissue of 0.125 ppb.

Multi-immunoaffinity chromatography: A simple and highly selective clean-up method for multi-anabolic residue analysis of meat

A method for the detection of nortestosterone (NT) in bovine muscle at levels below 1 μg/kg is described, based on enzymatic digestion of the sample, clean-up by immunoaffinity chromatography after defatting and detection by gas chromatography—mass spectrometry (selected-ion monitoring). The immunoaffinity matrix was prepared after combining the isolated immunoglobulin G fractions from a rabbit antiserum raised against NT and methyltestosterone (MT). Its capacity per millilitre of gel was approximately 10 ng for each of the two steroids. Results for samples containing 0.1 μg/kg NT and above are described. It is concluded that for multi-residue analysis of samples of muscle at levels as low as 0.1 μg/kg, multi-immunoaffinity chromatography is a very suitable method of sample clean-up. For purposes of quantification the trideuterated internal standard [16,16,17α- 2H 3]nortestosterone was synthesized.

Growth studies on juvenile tilapia using pure species, hormone-treated and nine interspecific hybrids

. The comparative growth performance of the juveniles of six pure tilapia species, Oreochromis mossambicus, O. spilurus, O. macrochir, O. aureus, O. niloticus and Sarotherodon galilaeus were assessed under standardized conditions in a recirculated water system. The effects of standardized treatments of 17α methyltestosterone and 17β estradiol were assessed by comparison with untreated controls of O. niloticus, O. mossambicus and O. aureus and the growth performance of nine interspecific hybrids in comparison to their parental species were studied. The results showed significant differences in growth rate for the strains of the pure species under the conditions used. Standardized hormone treatment had significant effects on sex ratios and growth performance of all the species studied but did not change their overall performance ranking when compared to the pure species. No hybrid performed significantly better than the best parent for SGR although O. aureus×O. niloticus hybrid was significantly better than O. niloticus when corrected weight gain was used. This work shows that species choice hormone treatment and hybridization have implications for tilapia culture.

Low tumorigenic response to 3,2'-dimethyl-4-aminobiphenyl administration in the prostate of rats castrated at birth.

Six‐week‐old rats which had been orchiectomized at birth were given 3,2′‐dimethyl‐4‐aminobiphenyl (DMAB) at various doses combined with a stimulus to prostate epithelial cell proliferation in the form of oral administration of methyltestosterone (MT) for 4 weeks. Thereafter MT treatment was continued or the animals received subcutaneous implants of testosterone propionate (TP) and were maintained until sacrifice at week 60. Although prostatitis and prostatic enlargement were frequently observed, especially in the TP group, numbers of atypical hyperplastic lesions were low and only one prostatic carcinoma in situ developed. Thus, despite the presence of proliferation, castration brought about a significant reduction in susceptibility to DMAB.

Induced sex reversal and spawning of blue-spotted grouper, Epinephelus fario

Attempts were made to induce sex reversal of under 2-year-old blue-spotted groupers and to induce spawning of 4-year-old females. Mature males, through sex reversal, were obtained successfully by the oral administration of methyltestosterone (MT) at daily feeding doses of 0.5 mg and 1.0 mg MT/kg body weight for 5 months. The sperm concentration was 8×10 7 cells/ml milt. The 2-year-old fish attained a sexually mature state in June and July with an average gonadosomatic index (GSI) of 2.07%. Changes in GSI and serum profile of estradiol-17β and 17α-testosterone were correlated with stage of gonad development, including vitellogenesis, sex transition and spermatogenesis. The values of GSI, serum estradiol and testosterone were elevated towards the completion of vitellogenesis and depressed during the sex transition phase. An increase in sex steroid concentrations, testosterone in particular, was recorded during spermatogenesis. Serum testosterone concentrations, ranging between 150 and 200 pg/ml serum in the prespawning season, gradually increased as vitellogenesis progressed and reached a level of 633 pg/ml serum in the mature females during the spawning season. Under the influence of MT administration, serum testosterone concentrations increased to 1100 pg and 1630 pg/ml serum at the end of a 170-day period at daily feeding doses of 0.5 mg and 1.0 mg MT/kg body weight, respectively. Spawning was induced by multiple injections of human chorionic gonadotropin (Puberogen) at doses of 2000–3000 IU HCG/kg fish. The frequency of hormone injections depended upon the stage of sexual maturity, as indicated by the stage of oocyte development and initial oocyte diameter. Two injections, 24 h apart, were found adequate when the recipient females contained mature oocytes at the tertiary yolk globule stage and a mean diameter of greater than 0.55 mm. For fish containing oocytes in the range of 0.50 to 0.55 mm, three injections were required to achieve successful spawning.

Short-term treatment with testosterone increases plasma 3,5,3′-triiodo- l-thyronine and hepatic l-thyroxine 5′-monodeiodinase levels in arctic charr, Salvelinus alpinus

Testosterone (T), methyl testosterone (MT), and testosterone propionate (TP) (0.5 mg/100 g body wt in 40 μl peanut oil) or peanut oil alone were injected (ip) on Days 0 and 3 into immature arctic charr ( Salvelinus alpinus). Chart were sampled on Days 7 and 12 and plasma testosterone, l-thyroxine (T 4), 3,5,3′-triiodo- l-thyronine (T 3), and hepatic microsomal T 45′-monodeiodinase (T 45′D) measured. Plasma androgen levels were elevated by all androgen treatments to levels similar to those observed in spawning salmonids. Plasma T 3 was significantly increased by all forms of testosterone on Days 7 and 12. T 4 levels remained unchanged or significantly decreased on Day 7, with no significant differences on Day 12. T 4 5′D activity was increased on both Days 7 and 12 in the experimental groups due to increases in the V max (1.3 to 5.9 × control groups) with negligible changes in the K m . In conclusion, T, MT, and TP all stimulate thyroidal status by increasing plasma T 3 levels in part as a result of increased hepatic T 45′D activity.

Transdermal Testosterone Treatment of Hypogonadal Men

Hypogonadism, either primary or secondary, results in diminished libido and/or impotence. Conventional treatment consists of periodic intramuscular injections (usually bimonthly) of a depot testosterone preparation or daily oral ingestion of methyl testosterone. These conventional treatments may be associated with side effects, such as gynecomastia, liver function abnormalities and edema. A new method of administering testosterone is by daily application of a transdermal therapeutic system. We studied the efficacy and safety of the transdermal therapeutic system in 4 hypogonadal men. Three patients were treated for 12 weeks and 1 for 7 weeks, and they were evaluated weekly. Of 4 patients 3 had improvement in erectile and/or sexual function. Mean plasma testosterone levels increased significantly compared to pre-treatment values during 7 of 12 treatment weeks. There were no adverse effects of the transdermal therapeutic system as indicated by serial physical examinations, daily reports, blood chemistry studies, liver function tests, urinalysis and hematological profiles. This preliminary report of transdermal testosterone delivery indicates that it may provide an effective alternative method of gonadal steroid replacement.

Effect of 17α‐Methyltestosterone Treatment and Withdrawal on Growth and Dietary Protein Utilization of Juvenile Rainbow Trout Fed Practical Diets Varying in Protein Level1,2

AbstractThe effects of 17α ‐methyltestosterone (MT) treatment and withdrawal on relative daily gain (RDG), protein gain (PG), productive protein value (PPV), and maximum efficient protein gain (MEPG) of juvenile rainbow trout fed practical diets varying in protein to metabolizable energy (P:ME) ratio were examined over an 18 week period. Two commercially available practical feeds with additions of dextrin and codliver oil were used to formulate diets containing 48% and 32% protein at approximately 320 kcal ME/100 grams with and without 2.0 mg MT/kg of dry diet. MT treated fish were fed hormone supplemented diets for 10 weeks (Phase 1) and hormone free diets for the final eight weeks (Phase 2) of the experiment. Control fish were fed hormone free diets for 18 weeks.MT treatment increased all growth and efficiency factors of fish during Phase 1. The increase in MEPG values due to MT treatment was more pronounced for fish fed the diet containing 48% protein than for fish fed the diet containing 32% protein. Hormone withdrawal reduced growth and efficiency values of fish to below the level of controls during Phase 2. Greater declines occurred for MT treated fish fed the diet containing 32% protein. No difference was observed between final mean RDC, PG, and MEPG values of fish initially fed MT and control fish calculated for the entire 18 weeks. Hormone withdrawal negated MT stimulated increases in empty carcass (EC) fat and whole body (WB) protein and decreases in EC and WB water contents that occurred in Phase 1. EC ash content was increased due to MT treatment and remained high through the period of withdrawal.

Lesions of the prostate glands and seminal vesicles induced by N-methylnitrosourea in F344 rats pretreated with ethinyl estradiol

In an attempt to induce a high incidence of prostate carcinoma, N-methylnitrosourea (MNU), a multipotential carcinogen, was given during the period of cell proliferation of the prostate gland induced by administration of methyltestosterone (MT) to F344 rats pretreated with ethinyl estradiol (EE). Rats were given diet containing EE for 3 weeks and then diet containing 300 ppm of MT for 5 days. On the 3rd day of MT-treatment, they were given a single intravenous injection of 50 mg/kg body wt. of MNU. Control rats (group 4) were given vehicle only. After treatment with MT for 5 days, the rats were given basal diet (group 1), diet containing MT (group 2) or diet periodically containing EE (groups 3 and 4) until the end of the experiment (week 60). Carcinoma of the prostate was found only in 1 or 17 rats in group 3. Atypical hyperplasia of the prostate was found in 1 of 10 rats in group 1 and 3 of 17 rats in group 2. The incidences of atypical hyperplasia of the seminal vesicles in groups 1–3 were 0%, 41% and 29%, respectively. No tumor promoting effect of MT or EE was observed except promotion by MT on the development of atypical hyperplasia of the seminal vesicles.

Lack of tumorigenic response in the prostate gland of castrated F344 rats by 3,2′-dimethyl-4-aminobiphenyl given with methyltestosterone

In an attempt to induce a high incidence of prostate carcinoma, 3,2′-dimethyl-4-aminobiphenyl (DMAB), a prostatic carcinogen, was given during the period of cell proliferation of the prostate gland induced by the administration of methyltestosterone (MT) to castrated F344 rats. Three weeks after the surgical castration, rats were given diet containing 300 ppm of MT for 2 weeks and basal for 2 weeks alternately 12 times. During each treatment with MT, one (group 1) or two (group 2) subcutaneous injections of 50 mg/kg body wt. of DMAB was given. After the last treatment of MT, a pellet of testosterone propionate (TP) was implanted in the subcutis of all animals until the end of the experiment (week 60). No carcinomas developed in the prostate gland of any of the rats. Atypical hyperplasia of the ventral lobe of prostate was found in 4 of 22 rats in group 1 and 2 of 20 rats in group 2. The incidences of atypical hyperplasia of the seminal vesicles in groups 1 and 2 were 64% and 75%, respectively. No pathological lesions in the prostate were observed in 32 rats given DMAB without MT treatment.

Effect of feeding high levels of androgens on the sex ratio of Oreochromis aureus

An experiment in which Oreochromis aureus fry were fed ethynyltestosterone (ET) at levels of 60, 90, 120, and 240 mg/kg of feed for 22 days at 27 to 32°C produced 100% male fish. Feeding methyltestosterone (MT) at levels of 60, 90, and 120 mg/kg of feed produced 96–99% males. Accidental overdosing of O. aureus fry with ET or MT (to the extent of 300% of recommended doses) should not hamper practical-scale production of monosex males.

Tissue distribution and elimination of radiolabelled methyltestosterone fed to adult blue tilapia

Radioactivity levels in 10 tissues were monitored for 21 days after adult (1-year-old) blue tilapia, Oreochromis aureus, were fed a single meal of a diet containing 30 μg unlabelled methyltestosterone (MT) per gram of feed and radiolabelled MT ( 3H-labelled steroid nucleus and 14C-labelled 17α-methyl group). Radioactivity was highest in all tissues 6–12 h after the feeding; about 90% of the radioactivity was in the digestive tract, liver, gall bladder, and kidney. Radioactivity declined nearly 90% by 4 days and only 0.5% of original radioactivity (67 ng/g of fish) remained after 21 days. Half of the remaining exogenous hormone was in digestive and excretory tissues; concentrations in muscle were less than 1 ng/g of tissue. Ratios of 3H: 14C in tissues were similar to those incorporated in the diet and suggested that the 17α-methyl group was not removed during metabolism.

Commercial methods for the control of sexual maturation in rainbow trout ( Salmo gairdneri R.)

Over half of the production of United Kingdom trout farms is accounted for by female-only stocks, and the use of sterile trout, particularly for sport fisheries and saltwater culture, is increasing. The practical sex control techniques by which these are produced were developed at this laboratory. They are suitable for use on technically unsophisticated farms, require no specialized equipment and are aesthetically acceptable to the consumer. The production of entirely female stocks requires phenotypically male broodstock of female genotype to fertilize eggs from untreated females. The sex-inversed males are produced by feeding fry for 700°C days with food containing 3 mg kg −1 17α methyltestosterone. The majority of the males lack sperm ducts, requiring the semen to be removed surgically, but reduced duration androgenization increases the proportion of males with intact ducts. No fish destined for human consumption are treated with hormones. Sterile trout are produced by the induction of triploidy in female eggs. Eggs are heatshocked at 28°C for 10 min, commencing 40 min after fertilization. Commercially acceptable levels of survival and sterility are achieved. This paper presents details of the techniques developed and considers the problems of applying genetic methods to commercial aquaculture.

Stimulatory effects of methyltestosterone on pituitary gonadotropic cells and testes leydig cells of the three-spined stickleback, Gasterosteus aculeatus L., in Winter

Male three-spined sticklebacks were kept for a month in short photoperiod at ca. 20° in winter. During this period methyltestosterone (MT), dissolved in the water (35 μg/liter), stimulated the appearance of breeding colors and kidney hypertrophy, characters which were both absent in the controls. MT furthermore prevented the onset of spermatogenesis. The gonadotropic cells of the MT-treated fish contained significantly more dilated endoplasmic reticulum and less granules than those of the controls. The nuclei of the testes Leydig cells were enlarged after treatment with MT. These findings suggest the existence of a positive feedback of androgen on the gonadal-pituitary axis of the male stickleback in winter.

Effects of 17β-estradiol and methyl testosterone on the activity of the thyroid gland in rainbow trout, Salmo gairdneri Richardson

Methyl testosterone (MT) and 17β-estradiol (E2), suspended either in sesame oil (and injected on alternate days) or in warm hydrogenated coconut oil (and injected once in the form of an “implant”), were administered intraperitoneally to nonvitellogenic rainbow trout ( Salmo gairdneri Richardson). When given as sesame oil injections E2 significantly reduced plasma triiodo- l-thyronine (T3) levels and thyroid epithelial cell height (TEH), but had no apparent effect on plasma l-thyroxine (T4) levels. When given as a coconut oil “implant” E2 significantly reduced both plasma T3 and T4 levels. E2 also elevated the hepatosomatic index (HSI), plasma Ca 2+, Mg 2+, protein, triglyceride, and alkali-labile phosphoprotein (ALP) and hepatic lipid concentration, decreased hepatic glycogen levels, but was without effect on plasma Na + and glucose levels. MT given via sesame oil injections significantly lowered plasma T3 levels, but was without effect on plasma T4 concentrations or TEH; the T3-lowering effect of MT was not evident when the steroid was given in the form of a coconut oil “implant”. MT also effected a lowering of plasma Mg 2+ and protein and hepatic lipid concentrations, but had no significant effect on HSI, plasma Na +, glucose triglyceride and ALP concentration, or hepatic glycogen levels. MT given as a series of injections lowered plasma Ca 2+ levels, but was without effect when given as an “implant” and had no significant effect on plasma Ca 2+. Intraperitoneal injections of ovine thyrotropin (TSH) (2 μg/g body wt) elicited an increase in both plasma T4 and T3 levels within 24 hr in E2-, MT-, and oil-injected groups. The TSH-stimulated increase in plasma T4 level was significantly less in the E2-treated fish compared with oil- or MT-treated groups. The TSH-stimulated increase in plasma T3 levels in both groups of steroid-treated fish was significantly less than that of the oil-injected controls.

Hormonal sex reversal of wild‐spawned tilapia in India

The effectiveness of methyltestosterone (MT) for sex reversal and growth promotion in Oreochromis mossambicus was studied in culture experiments in India. Wild‐spawned fry were treated with 30 μg MT g−1 diet for 30 or 60 days at two feeding levels (initially 20% or 10% of body weight daily). The fish were grown on for 66–96 days after the hormone treatment period in fertilized cement ponds without supplementary feeding. Tilapia treated with MT for 60 days attained an average weight of 29.0 g compared to 18.8 g for untreated fish reared under similar conditions. The percentage of males among the untreated tilapia was 58%, MT treatment for 30 days significantly increased this percentage at the higher feeding level (79% male), but not at the lower feeding level (51%). More than 90% of the tilapia in both 60 day MT treatment groups were male; 3% of all the fish reared showed an intersex condition. The experiments demonstrated that the anabolic and sex reversal effects of MT on tilapia are proportional to the duration of treatment and quantity of hormone administered. The possible application of monosex tilapia culture in tropical countries is noted.

A chemiluminescent immunoassay for 17α‐methyltestosterone

An immunoassay for the xenobiotic anabolic compound methyltestosterone (MT) is presented. The detection is based on chemiluminescence of a MT-isoluminol conjugate. Applications are presented for detection of methyltestosterone and cross-reacting compounds in bovine urine and tissues of application sites isolated from slaughtered cattle, illegally treated with hormonal anabolics.

The effect of oral medroxyprogesterone acetate and methyltestosterone on sexual functioning in a male contraceptive trial

Twenty-three men who participated in a 15-month clinical trial to assess the potential effectiveness of using a combination of varying doses of medroxyprogesterone acetate (MPA) and methyltestosterone (MT) as a male contraceptive agent, completed a “sexual problem checklist” every two weeks. The study was divided into three phases: pre-treatment (3 months), treatment (6 months), post-treatment (6 months). The questionnaire evaluated changes in various aspects of sexual behaviour and sexual perception and explored whether the treatment influenced any of the parameters considered. The results indicated a small, but significant, decrease in subjective assessment of sexual drive. This was not, however, accompanied by a change in sexual behaviour, in that subjects experienced the same number of erections, ejaculations and frequency of intercourse. It is concluded that the combination of MPA and MT in the doses used may produce a slight decrease in subjective assessment of sexual drive, but no change in actual sexual behaviour.

Stimulation of estradiol production from estrone-3-sulfate by 5α-dihydrotestosterone in cultured human placental explants

The effect of androgens on the conversion of estradiol (E 2) and estrone (E 1) from estrone-3-sulfate (E 1-S) was studied in explants of normal human term placentas. Explants incubated in medium supplemented with 2.0 μM E 1-s showed that 50 μM dihydrotestosterone (DHT) stimulated E 2 production 15-fold above control values after 0.5 h, but neither 50 μM methyltestosterone (MT) nor 50 μM diethylstilbestrol (DES) had any effect. HCG (5.0i.u./ml), alone or in combination with one of the androgens, did not influence the E 2 production. When the explants were incubated in medium with 0.25μM E 1-S (the average concentration reported for late pregnancy plasma), DHT (0.5–50μm) caused a dose- and time-dependent increase in E 2 production, while E 1 production and the combined accumulation of E 2 and E 1 were slightly inhibited by all doses of DHT during the 0.5–4 h incubation. When E 1 (O.1 μM) was used as substrate, DHT caused a dramatic dose- and time-dependent shift in the E 1-E 2 equilibrium towards E 2. The results indicate that during late pregnancy, a particular class of androgens may increase the production of the more bioactive E 2 from the circulating E 1-s; the mode of action may be an enhanced conversion of E 1 to E 2.