Effects Of Methyltestosterone Research Articles

Sexual differentiation and sex reversal in tilapia (Oreochromis niloticus) by hormone 17 α methyltestosterone similar to that used in cultivation systems

The hormone 17 α methyltestosterone (MT) is commonly used in the farming of tilapia, which is a gonochoristic species, for the obtainment of a male mono-sex population to avoid reproduction during grow-out and due to the fact that males present greater growth, making cultivation commercially more lucrative. Larvae were collected and experimentally received MT in the feed for 30 days in a similar way as that performed in commercial farming. Physiological events of sexual differentiation and the moment in which sex reversal promoted by MT occurred were documented with the use of histological and morphometric methods. On the first day of receiving feed with MT, the fish presented gonads with undifferentiated germ cells. On the 12th day of exogenous feeding with and without MT, sexual differentiation of the gonads was observed morphologically, demonstrated by the formation of the ovarian cavity in females. Males continued to have undifferentiated gonads for a longer period. Sex reversal occurred in all females treated with MT at 25 days after the onset of exogenous feeding. The results indicate that treatment for sex reversal used in commercial farming systems could be shorter than that customarily employed, diminishing the quantity of synthetic hormone released into the environment and reducing the harmful effects of MT on other aquatic organisms. Therefore, the data suggest the possibility of reducing the use of hormone MT by 5 days.

Effects of MT on growth and gonad development of natural overwintering Whitmania pigra

The objectives of study were to explore the effects of exogenous methyltestosterone( MT) on the growth and gonadal development of overwintering Whitmania pigra. Before overwintering,0. 1,1. 0,10. 0,100. 0,150. 0 μg·L-1 of MT were added to the aquaculture water for 6 weeks. The changes of growth performance,gonad index,endogenous steroid hormones level and internal quality were measured after hibernate for 60 days. Then the tissue slice technique was used to observe the spermary( ovary) of Wh. pigra.The results showed that the body weight,survival rate and gonadal index increased first and then decreased with the increase of exogenous MT concentration; the male gland index was found the highest at the concentration of MT 10. 0 μg·L-1 and the female gland index was the highest at the concentration of MT 1. 0 μg·L-1. The survival rate of Wh. pigra peaked at the concentration of MT 10. 0 μg·L-1.The weight reaches a peak at a concentration of MT 100. 0 μg·L-1( P<0. 05). The number of primary spermatocytes in the testis was negatively correlated with the concentration of exogenous MT. The number of secondary spermatocytes and sperm cells increased first and then decreased. The concentration of secondary spermatocytes was the highest when the concentration of MT was 100. 0 μg·L-1.The number and volume of oocytes in the ovary and the yolk granules increased first and then decreased with the increase of exogenous MT concentration,and the highest was observed at the MT concentration of 100. 0 μg·L-1. The endogenous steroid hormone of Wh.pigra increased first and then decreased with the increase of exogenous MT concentration. The concentration of androgen and progesterone was the highest in MT 100. 0 μg·L-1 treatment( P<0. 05),and the concentration of estrogen was found the highest in MT 10. 0 μg·L-1 treatment( P<0. 05). After adding exogenous MT,Wh. pigra moisture content,acid-insoluble ash content,p H and anti-thrombin activity met the quality criterion of medicinal Wh. pigra in Chinese Pharmacopoeia( 2015 edition). In conclusion,the short-term addition of 1. 0-100. 0 μg·L-1 exogenous MT before hibernation can promote the growth,the development of sperm cells and the antithrombin activity of Wh. pigra.

Effects of Methyltestosterone on Masculinization in Larva and Juvenile of the Spotted Halibut Verasper variegatus

Effects of Methyltestosterone on Masculinization in Larva and Juvenile of the Spotted Halibut Verasper variegatus

Effects of methyltestosterone, letrozole, triphenyltin and fenarimol on histology of reproductive organs of the copepod Acartia tonsa

The marine calanoid copepod Acartia tonsa was exposed to methyltestosterone (MET, 1.6–126μgL−1), letrozole (LET, 10–1000μgL−1), triphenyltin chloride (TPT, 0.0014–0.0088μgL−1 TPT-Sn) and fenarimol (FEN, 2.8–105μgL−1) for 21d covering a full life-cycle. All four compounds investigated are known to act as androgens in vertebrates. The digestive tract, musculature, nervous system, reproductive organs, gonad and accessory sexual glands were examined by light microscopy after routine staining and immune-labelling for detection of apoptosis and determination of proliferation activities. MET induced an inhibition of oogenesis, oocyte maturation and yolk formation, respectively, which was most pronounced at the lowest concentrations tested. In LET exposed males, spermatogenesis was enhanced with very prominent gamete stages; in some stages apoptosis occurred. The spermatophore was hypertrophied and displayed deformations. In females, LET induced a disorder of oogenesis and disturbances in yolk synthesis. TPT stimulated the male reproductive system at 0.0014 and 0.0035μg TPT-SnL−1, whereas inhibiting effects were observed in the female gonad at 0.0088μg TPT-SnL−1. In FEN exposed females proliferation of gametes was reduced and yolk formation showed irregular features at 2.8–105μgL−1. In FEN exposed males an elevated proliferation activity was observed. No pathological alterations in other organ systems, e.g. the digestive tract including the hindgut acting as respiratory organ, the nervous system, or the musculature were seen. This indicates that the effects on gonads might be caused rather by disturbance of endocrine signalling or interference with hormone metabolism than by general toxicity.

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.

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.

Neuropsychological Effects of Methyltestosterone in Women Using Menopausal Hormone Replacement

To observe the effects of androgen replacement on neuropsychological measures in menopausal women, healthy menopausal women already using replacement estrogen were studied in a randomized, double-blind, active placebo-controlled, crossover comparison between two 8-week periods of treatment with (1) 0.625 mg oral esterified estrogen (E) alone and (2) in combination with 1.25 mg oral methyltestosterone (meT). After an initial baseline session, data were gathered at the end of two treatment periods. Scores on standardized psychological tests and computerized reaction times were compared between treatments, as was an overall outcome score that combined all measures. Added meT significantly improved scores on a test of complex information processing, the Switching Attention Test, but not on other tests. Mean outcome score showed no net change and wide variation. Fourteen subjects had outcome scores >1 SD from the mean, and 21 had no change. In the estrogen alone condition, three measures predicted favorable outcome with added meT: surgically compromised ovarian function, fewer physical symptoms, and higher score on a self-image measure of creativity. Added meT treatment may improve complex information processing. Despite wide disparities in outcome, an increased chance of overall improvement may be predicted by specific pretreatment measures.

Effects of methyltestosterone on insulin secretion and sensitivity in women.

The frequent coexistence of hyperandrogenism and insulin resistance is well established; however, whether a cause and effect relationship exists remains to be established. In this study we tested the hypothesis that short-term androgen administered to women would induce insulin resistance. To test this hypothesis, regularly menstruating, nonobese women were studied before and during methyltestosterone administration (5 mg tid for 10-12 days) by the hyperglycemic (n=8) and euglycemic, hyperinsulinemic (n=7) clamp techniques. Short-term methyltestosterone administration had no significant effects on the fasting levels of glucose, insulin, c-peptide, glucagon, or glucose turnover. During the hyperglycemic clamp studies, the mean glucose level during the final hour was 203+/-2 and 201+/-1 mg/dL in the methyltestosterone and control studies, respectively. The insulin response to this hyperglycemic challenge was slightly but not significantly greater during methyltestosterone treatment (first phase 59+/-8 vs. 50+/-8 microU/mL in controls; second phase 74+/-9 vs. 67+/-9 microU/mL in controls; total insulin response 133+/-16 vs. 117+/-15 microU/mL in controls). In spite of this, glucose uptake was reduced from the control study value of 10.96+/-1.11 to 7.3+/-0.70 mg/kg/min by methyltestosterone (P < 0.05). The ratio of glucose uptake per unit of insulin was also significantly reduced from a control study value of 14.3+/-1.4 to 9.4+/-1.3 mg/kg/min per microU/mL x 100 during methyltestosterone administration. In the euglycemic hyperinsulinemic clamp studies, insulin was infused at rates of 0.25 and 1.0 mU/kg/min to achieve insulin levels of approximately 25 and 68 microU/mL, respectively. During low-dose insulin infusion, rates of endogenous hepatic glucose production were equivalently suppressed from basal values of 2.37+/-0.29 and 2.40+/-0.27 mg/kg/min to 0.88+/-0.25 and 0.77+/-0.26 mg/kg/min in the methyltestesterone and control studies respectively. Whole body glucose uptake during low-dose insulin infusion was minimally affected. During the high-dose insulin infusion, endogenous hepatic glucose production was nearly totally suppressed in both groups. However, whole body glucose uptake was reduced from the control value of 6.11+/-0.49 mg/kg/min to 4.93+/-0.44 mg/kg/min during methyltestosterone administration (P < 0.05). Our data demonstrate that androgen excess leads to the development of insulin resistance during both hyperglycemic and euglycemic hyperinsulinemia. These findings provide direct evidence for a relationship between hyperandrogenemia and insulin resistance, and its associated risk factors for cardiovascular disease.

Effects of Methyltestosterone on Insulin Secretion and Sensitivity In Women

Effects of Methyltestosterone on Insulin Secretion and Sensitivity In Women

Effects of methyltestosterone on food utilization and growth of Sarotherodon niloticus fry.

Three groups of Sarotherodon niloticus fry were fed for 8 weeks on diets either treated with 17α-methyltestosterone (MT), alcohol (CA), or untreated (CO). Growth rate and food utilization in the different groups were compared. Results indicate that the best growth, Food Conversion Ratio (FCR), Protein Efficiency Ratio (PER) and Mean Growth Rate (MGR) were obtained with the MT diet. There was no significant difference (P>0.05) in growth and food utilization of the CA and CO fry, nor in the mortality rate of the three treatments. The androgen methyltestosterone promotes growth and protein anabolism without producing toxic effects in S. niloticus.

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.

Testosterone-dependent transformation of nephronic tubule cells into serous and mucous gland cells in stickleback kidneys in vivo and in vitro

When male sticklebacks come into breeding condition, the cells of the second proximal segments and collecting tubules of the nephrons are transformed into cells producing secretions used for nest building. This investigation is aimed at determining whether this transformation of renal tubule cells is induced directly by androgens. To this end, renal tissue is cultured with androgen supplement, either methyltestosterone or 11-ketotestosterone. The results are compared with the effects of methyltestosterone on the tubule cells in castrated males. In the nephronic tubules of methyltestosterone-treated fish, the basal labyrinth—and thus most of the ion reabsorbing capacity of the tubules—disappears within 4 days, probably as a result of autophagous digestion. During this period the cells become considerably enlarged and an extensive granular endoplasmic reticulum develops. The Golgi apparatus proliferates and starts to form secretory granules. In renal tissue cultured for 10 days with methyltestosterone, secretory granules are observed in the second proximal tubule cells, but no secretory activity can be detected in the collecting tubules. After 5 days in cultures supplemented with 11-ketotestosterone, however, signs of secretory activity are apparent already in the second proximal tubules, and to a lesser extent, in the collecting tubules. After 10 days of incubation with 11-ketotestosterone, glandular transformation is almost completed. The results provide strong evidence that the transformation of nephronic tubule cells into mucus-secreting cells in sexually mature sticklebacks is due to a direct effect of androgen. It can be concluded then that, at least in vitro, 11-ketotestosterone may be considered more androgenic than methyltestosterone.

Effects of methyltestosterone on spermatogenesis and secondary sexual characters in the three-spined stickleback ( Gasterosteus aculeatus L.)

Methyltestosterone administered via the water (35 μ/liter) at the end of the breeding season prevented involution of secondary sexual characters (high kidney epithelium) and prevented initiation of spermatogenesis in male three-spined sticklebacks. In control males regression of kidney and initiation of spermatogenesis were strongly correlated.

The Effects of Methyltestosterone on Sex Reversal in Bluegill

The Effects of Methyltestosterone on Sex Reversal in Bluegill

Effects of methyltestosterone on the skin and the gonad of salmonids

Oral administration of methyltestosterone caused dark yellow coloration and a thickening of the skin in young pink salmon. This thickening of the skin was due partly to the hypertrophy of mucous cells and of cells in the stratum germinativum in the epidermis. The mucous cells became active in mucous secretion. Furthermore, the upper layer of the dermis became thick and dense and enclosed the scales after 2 weeks. Descaling was inhibited by the treatment. All ovarian eggs had degenerated and spermatogenesis was suspended. Some spermatogonia became hypertrophic and developed vacuoles in the cytoplasm. Hypertrophic changes were also observed in interstitial-like cells and in the cells lining the sperm duct, accompanied by active secretion of a liquid material. No large differences were observed between dosages of concentrations of 50 and 100μg/g diet. Similar changes were observed in chum salmon.

Effects of methyl testosterone on the testis and secondary sex characters of the hypophysectomized adult guppy Poecilia reticulata Peters.

Exogenous methyl testosterone appears to have a direct spermatokinetic effect on the testis of the hypophysectomized adult guppy. The gonosomatic index is significantly increased; spermatogonial cysts divide rapidly and transform into spermatocytes, but later stages of spermatogenesis do not appear. The regressed epithelial cells lining the sperm ducts, the Sertoli cells, and the interstitial cells resume their normal appearance. The gonopodium remains unaffected, but there is moderate recovery in the content of integumentary lipophores.

EFFECTS OF METHYL TESTOSTERONE UPON SERUM LIPIDS.

The effect of a placebo or methyl testosterone in conjunction with a low fat, low cholesterol diet was studied in a double-blind fashion. The only significant change in the lipid fractions in the placebo group was a mean increase of 5.5 mg/100 ml in the alpha lipoprotein cholesterol. Thirty patients were followed for 1 year. In a group of 34 patients who received 10 mg of oral methyl testosterone daily, the only significant change was a mean decrease of 4.6 mg/100 ml in the alpha lipoprotein cholesterol, with a mean rise of 19 mg/100 ml in the beta fraction, resulting in an increase of 1.4 in the beta/alpha lipoprotein cholesterol ratio. The concentration of total cholesterol and phospholipids was unchanged. With daily doses of 25, 50 and 100 mg of methyl testosterone in smaller groups of men, the alpha lipoprotein cholesterol decreased to 31.9, 31.3 and 20.7 mg/100 ml, as the beta lipoprotein cholesterol increased to 196, 208 and 232 mg/100 ml, respectively. The beta to alpha lipoprotein cholesterol rati...

Effects of methyl testosterone on thyroid function, thyrozine metabolism, and thyroxine-binding protein.

Studies on the effect of androgenic steroids on thyroid function are difficult to evaluate because of a number of apparent discrepancies. Money, Kirschner, Kraintz, Merrill, and Rawson (1), using castrate rats on a low iodine diet, found that testosterone propionate had no influence on thyroid weight or on thyroid weight: body weight ratio, but did increase the radioiodine uptake. Kochakian and Evans (2) recently reported that this form of testosterone failed to influence the uptake or release of radioiodine by the thyroid of the castrate rat. Burris, Bogart, and Krueger (3), using heifers and young steers, found that testosterone propionate produced an increased gain in weight; furthermore, the thyroids of the treated animals weighed more, contained less colloid, and exhibited an increase in thyroid cell height. Voitkevich (4) is cited as stating that the goiters produced by propylthiouracil in guinea pigs and cocks are very considerably decreased by simultaneously administered methyl testosterone, and that propylthiouracil goiters are larger in castrate than -in normal cocks.

Adverse effects of methyltestosterone in lymphomas.

Adverse effects of methyltestosterone in lymphomas.

METHYLTESTOSTERONE TREATMENT OF PREMATURE INFANTS

THE REPORTS on the beneficial effects of methyltestosterone for premature infants vary. Shelton and Varden 1 and Shelton, Varden, and Mark 2 found it of benefit in two series of premature infants in decreasing the expected mortality, increasing the daily weight gain, and shortening the hospital stay. Hardy and Wilkins 3 and Seitchik and Agerty 4 in their two series did not find any beneficial results over ordinary nursery treatment of premature infants. Earle, 5 using methyltestosterone and plasma orally, found them of benefit in increasing daily weight gain and in shortening the hospital stay; however he was unable to attribute his results to methyltestosterone alone, to plasma alone, or to the combination of methyltestosterone and plasma. In an effort to evaluate further the use of methyltestosterone, 6 50 premature infants, including four sets of twins, were studied. All premature infants were handled by a standard nursery regimen. Feedings consisted