Objective To investigate the feasibility and optimal regimen of orally administration of low dose gossypol acetic acid （GA） combined with methyltestosterone （MT） plus ethinyl estradiol （EE） for contraception in ...Objective To investigate the feasibility and optimal regimen of orally administration of low dose gossypol acetic acid （GA） combined with methyltestosterone （MT） plus ethinyl estradiol （EE） for contraception in males.Methods Wistar male rats were randomly assigned into four groups, 20 in each group. Animals in group A or B were administered daily with 1% methyl cellulose or GA （12 mg/kg） suspended in 1% methyl cellulose, respectively. Rats in group C or D took firstly GA 12 mg/kg＋MT 20 mg/kg＋EE 0.1 mg/kg or MT 20 mg/kg＋EE 0.1 mg/kg, in asuspension with 1% methyl cellulose, via gastric intubation. After the infertilities were initiated（6 weeks for group C, 8 weeks for group D）, GA was served alone while MT＋EE were withdrawn in rats of groups C and D. The treatment was ceased after 18 weeks and some males from group C were permitted to recover. Fertility testing, 10 males per group, was served for determining infertility or restoration of fertility in treated rats. Examinations of histology and biochemistry in treated rats were used to examine the morphologic influences on sperm, testis, epididymides and viscera, and biochemical changes in blood. The growth and development of F1 generation of the rats would also be tested in a series of behavioral tests.Results Ten rats from group C were infertile at week 6 after treatment, and the fulfilled infertility was maintained with low-dose GA （12 mg/kg） only daily. Six weeks after cessation of treatment, all of treated males recovered their fertility. However, 8 of 10 rats from group D were in sterility at 6th week of treatment and all at 8th week of treatment, but the infertility could not be kept with the similar dose GA alone later on. Moreover, no adverse effects were found in our present experiments.Conclusion Administration of oral low dose GA combined with MT and EE as loading dose could successfully induce infertility in short term, whereafter the efficacy could completely be maintained by similar low dose of GA alone for long term. The combined regimen should be safe, effective, reversible and long term, and then optimal and promised contraception for male.展开更多
The effects of recombinant eel growth hormone (reGH).methyltestosterone (MT)and L-thyroxine (T4)on the growth of red sea bream. Pagrosomus major.were investigated.Administration of reGH to fry by immersion at 2 mg 1 f...The effects of recombinant eel growth hormone (reGH).methyltestosterone (MT)and L-thyroxine (T4)on the growth of red sea bream. Pagrosomus major.were investigated.Administration of reGH to fry by immersion at 2 mg 1 for 2 hevery 5 dsys resulted in significant increase in both weight and length.but the condition factor (CF) diminished relative to that of similarly treated controls over the 37day treatment period.Immersion in 0.1 mg:1 T4 also resulted in significant increase in both weight and length and higher survival rate of test fry compared to the controls. Immersion in MT had less effect on growth and high-dose resulted in high mortality.In the second study.injection of 2 μg reGH(gwk)caused a significant increase in the specific growth rate (SGR) of test red sea bream fingerlings relative to that of the controls during the 4-week treatment period and maintained the increasing trend over the post-treatment period (weeks 4-6).Injection of MT at a dosage of 1μg (gwk) resulted in a significant展开更多
The use of synthetic anabolic steroid methyltestosterone (MT) as growth promoter is prohibited in China. Vali-dations of analytical methods for MT residue in food and the results obtained have become indispensable. Th...The use of synthetic anabolic steroid methyltestosterone (MT) as growth promoter is prohibited in China. Vali-dations of analytical methods for MT residue in food and the results obtained have become indispensable. The high perfor-mance liquid chromatography (HPLC) method for the detection of MT with liquid-liquid extraction by trichloromethane-methanol in carp muscle tissue was preliminarily validated with reference to the following parameters: recovery (accuracy)at the 1, 5 and 10mg kg-1 level, between-run and within-run CV values (repeatability, also called relative standard deviation(RSD)) and limit of detection. The recoveries were above 80% and the between-run and within-run CV values below 10%for muscle tissue. The limit of detection was 0.05 mg kg-1.展开更多
文摘Objective To investigate the feasibility and optimal regimen of orally administration of low dose gossypol acetic acid （GA） combined with methyltestosterone （MT） plus ethinyl estradiol （EE） for contraception in males.Methods Wistar male rats were randomly assigned into four groups, 20 in each group. Animals in group A or B were administered daily with 1% methyl cellulose or GA （12 mg/kg） suspended in 1% methyl cellulose, respectively. Rats in group C or D took firstly GA 12 mg/kg＋MT 20 mg/kg＋EE 0.1 mg/kg or MT 20 mg/kg＋EE 0.1 mg/kg, in asuspension with 1% methyl cellulose, via gastric intubation. After the infertilities were initiated（6 weeks for group C, 8 weeks for group D）, GA was served alone while MT＋EE were withdrawn in rats of groups C and D. The treatment was ceased after 18 weeks and some males from group C were permitted to recover. Fertility testing, 10 males per group, was served for determining infertility or restoration of fertility in treated rats. Examinations of histology and biochemistry in treated rats were used to examine the morphologic influences on sperm, testis, epididymides and viscera, and biochemical changes in blood. The growth and development of F1 generation of the rats would also be tested in a series of behavioral tests.Results Ten rats from group C were infertile at week 6 after treatment, and the fulfilled infertility was maintained with low-dose GA （12 mg/kg） only daily. Six weeks after cessation of treatment, all of treated males recovered their fertility. However, 8 of 10 rats from group D were in sterility at 6th week of treatment and all at 8th week of treatment, but the infertility could not be kept with the similar dose GA alone later on. Moreover, no adverse effects were found in our present experiments.Conclusion Administration of oral low dose GA combined with MT and EE as loading dose could successfully induce infertility in short term, whereafter the efficacy could completely be maintained by similar low dose of GA alone for long term. The combined regimen should be safe, effective, reversible and long term, and then optimal and promised contraception for male.
文摘The effects of recombinant eel growth hormone (reGH).methyltestosterone (MT)and L-thyroxine (T4)on the growth of red sea bream. Pagrosomus major.were investigated.Administration of reGH to fry by immersion at 2 mg 1 for 2 hevery 5 dsys resulted in significant increase in both weight and length.but the condition factor (CF) diminished relative to that of similarly treated controls over the 37day treatment period.Immersion in 0.1 mg:1 T4 also resulted in significant increase in both weight and length and higher survival rate of test fry compared to the controls. Immersion in MT had less effect on growth and high-dose resulted in high mortality.In the second study.injection of 2 μg reGH(gwk)caused a significant increase in the specific growth rate (SGR) of test red sea bream fingerlings relative to that of the controls during the 4-week treatment period and maintained the increasing trend over the post-treatment period (weeks 4-6).Injection of MT at a dosage of 1μg (gwk) resulted in a significant
文摘The use of synthetic anabolic steroid methyltestosterone (MT) as growth promoter is prohibited in China. Vali-dations of analytical methods for MT residue in food and the results obtained have become indispensable. The high perfor-mance liquid chromatography (HPLC) method for the detection of MT with liquid-liquid extraction by trichloromethane-methanol in carp muscle tissue was preliminarily validated with reference to the following parameters: recovery (accuracy)at the 1, 5 and 10mg kg-1 level, between-run and within-run CV values (repeatability, also called relative standard deviation(RSD)) and limit of detection. The recoveries were above 80% and the between-run and within-run CV values below 10%for muscle tissue. The limit of detection was 0.05 mg kg-1.
