Aim: To ascertain whether the side effects of gossypol, hypokalemia and irreversibility, could be avoided on dose re-duction. Methods: Seventy-seven male volunteers were divided into 3 groups: control (22 cases), 10 m...Aim: To ascertain whether the side effects of gossypol, hypokalemia and irreversibility, could be avoided on dose re-duction. Methods: Seventy-seven male volunteers were divided into 3 groups: control (22 cases), 10 mg gossypol(29 cases) and 12.5 mg (26 cases). Serum levels of testosterone, FSH and LH were measured by RIA and potassiumby flame photometry. Spema counts and motility were examined before and regularly after treatment for the evaluationof contraceptive efficacy. Results: The average sperm density and motility started to decrease significantly by theend of month 2 of medication and gradually reached the infertility levels ( < 4 million /mL) in both treated groups. Af-ter that the 10 mg group was asked to take the same dose every other day for up to a total observation period of 16-18months for the maintenance of infertility. Subjects in the 12.5 mg group did not take gossypol any more so as to ob-serve the length of the loading dose required, but in a few, a maintenance dose of 12.5 mg every other day was insti-tuted for a few more months. In both treated groups, none of the spouses was pregnant during the maintenance dose pe-riod. Serum levels of potassium, FSH, LH and testosterone were not significantly changed and not a single volunteercomplained of myoasthenia. After cessation of drug administratioin, the semen data returned to pretreatment levels.Conclusion: A regimen with 10 or 12.5 mg of gossypol as the daily loading dose and 35 or 43.75 mg as the week-ly maintenance dose could induce infertility in male volunteers without developing hypokalemia or irreversibility.(Asian J Androl 2000 Dec; 2: 283-287)展开更多
This review provides an overview of the literature on aspects of reproductive endocrinology wherein Asian menmay differ from Caucasian, notably, prostatic nioplasm and the sensivity to pharmacological regimens of male...This review provides an overview of the literature on aspects of reproductive endocrinology wherein Asian menmay differ from Caucasian, notably, prostatic nioplasm and the sensivity to pharmacological regimens of male contra-ception. Both genetic and environmental factors, such as nutrition, might be relevant. Asian men residing in Asia seemto be relatively protected from clinical prostatic nioplasm while the prevalence of preclinical prostatic nioplasm is notdifferent. Migration to an area with a higher prevalence reduces this difference but does not undo it. With regard toprostatic nioplasm the following factors have been considered as relevant in Asian men: 1) a reduction in 5α-reductaselevel, 2) decreased levels of androgenic ketosteroid precursors of 5α-reduced androgen metabolites, 3) the decreasedpresence of a P53 mutation, 4) a higher CAG-repeat length of the androgen receptor, 5) a possible higher level ofphysical activity, 6) differences in sexual activity. Furthermore, Asian men respond to a higher degree with azoosper-mia in response to contraceptive steroids. Possible explanations offered for the more pronounced response to contracep-tive steroids are: 1) differences in testicular structure and decreased spermatogenic potential, 2) an earlier and moremarked suppression in LH secretion by exogenous androgens. The differences may be due to genetical and/or environ-mental factors influencing the peripheral testosterone metabolism. Dietary factors such as the higher intake of phytoe-strogens in Asians might exert effects on 5α-reductase activity and/or on sex hormone binding globulin (SHBG) levels,thus having an impact on the biological efficay of circulating androgens. ( Asian J Androl 2000; 2: 13 - 20)展开更多
Development of an ideal hormonal contraceptive for man has been the goal of several research workers during thepast few decades. Suppression of pituitary gonadotropic hormones, which in turn would inhibit spermatogene...Development of an ideal hormonal contraceptive for man has been the goal of several research workers during thepast few decades. Suppression of pituitary gonadotropic hormones, which in turn would inhibit spermatogenesis whilemaintaining normal libido and potentia has been the approach for a contraceptive agent. Intramuscularly administeredand orally active testosterone or testosterone in combination with progesterone have been shown to cause inhibition ofspermatogenesis resulting in azoospermia in normal men. Similarly testosterone has been used in combination with go-nadotropin releasing hormone antagonists and agonists to inhibit pituitary gonadotropic hormone release. Immunologicalapproach to neutralize the circulating levels of follicle stimulating hormone has also been shown to cause inhibition ofspermatogenesis. The available literature shows that testosterone causes reversible azoospermia without any significantside effects in Asian population effectively and appears to be a promising chemical for control of fertility in man.展开更多
Effective regulation of human fertility has global consequences in terms of resource depletion, pollution and pover-ty. Current family planning services predominantly target a female clientele with few significant dev...Effective regulation of human fertility has global consequences in terms of resource depletion, pollution and pover-ty. Current family planning services predominantly target a female clientele with few significant developments in malefertility regulation for over a century. The last two decades have witnessed a gathering interest, initially from the scien-tific community, and laterally from industry, in the development of safe, reliable, reversible methods of contraceptionfor men. This review summarises the methods of male fertility regulation which are currently available and critically ex-amines the published data on novel developments in male hormonal contraception which offer the potential of improvedcontraceptive choice for all in new millennium. (Asian J Androl 2000; 2: 3 - 12)展开更多
Aim: The rationale and technique underlying a novel concept of non-invasive removal of an intravasal vas deferens poly-meric contraceptive drug to reverse drag injection-induced azoospermia are explained. Thus the con...Aim: The rationale and technique underlying a novel concept of non-invasive removal of an intravasal vas deferens poly-meric contraceptive drug to reverse drag injection-induced azoospermia are explained. Thus the conventional methods ofsurgical exploration to remove vas deferens plugs and intravasal injection of solvents to flush out contraceptive drugs are tobe replaced by steps which will be readily accepted by subjects. Methods: The approach is based upon the non-invasiveapplication of specific forces to various segments of the vas deferens so that non-sclerosing and non-tissue-adherent com-pounds, in particular styrene maleic anhydride (SMA) can be expelled. Forces are generated by palpation; percuta-neous electrical stimulation; vibration application; and percussion. The forces help to propel the intravasal polymer to-wards the ejaculatory duct for expulsion during ejaculation. All aspects of the total technique are clinically acceptable,simple, atraumatic, unlikely to cause pain and discomfort even without tranquilizers, local or general anaesthetics. Theprocedure may be repeated several times in different sittings spaced apart by about one week to achieve adequate plug ex-pulsion. Results: Model experiments demonstrated the feasibility of the concept. The polymer was nonadherent andcould be moved within the vas deferens by the application of specific forces. Sufficient removal was possible to enablespermatic fluid to be transported along a region previously occupied by the polymer. A corroborating subhuman primatestudy by an independent investigator has shown that the semen profile becomes normal following the reversal. Conclu-sion: Adoption of the new technique may provide a means of non surgical restoration of normal semen profile after a pe-riod of fertility control obtained by intravasal drag injection. (Asian J Androl 1999 Sep ; 1: 131 - 134)展开更多
文摘Aim: To ascertain whether the side effects of gossypol, hypokalemia and irreversibility, could be avoided on dose re-duction. Methods: Seventy-seven male volunteers were divided into 3 groups: control (22 cases), 10 mg gossypol(29 cases) and 12.5 mg (26 cases). Serum levels of testosterone, FSH and LH were measured by RIA and potassiumby flame photometry. Spema counts and motility were examined before and regularly after treatment for the evaluationof contraceptive efficacy. Results: The average sperm density and motility started to decrease significantly by theend of month 2 of medication and gradually reached the infertility levels ( < 4 million /mL) in both treated groups. Af-ter that the 10 mg group was asked to take the same dose every other day for up to a total observation period of 16-18months for the maintenance of infertility. Subjects in the 12.5 mg group did not take gossypol any more so as to ob-serve the length of the loading dose required, but in a few, a maintenance dose of 12.5 mg every other day was insti-tuted for a few more months. In both treated groups, none of the spouses was pregnant during the maintenance dose pe-riod. Serum levels of potassium, FSH, LH and testosterone were not significantly changed and not a single volunteercomplained of myoasthenia. After cessation of drug administratioin, the semen data returned to pretreatment levels.Conclusion: A regimen with 10 or 12.5 mg of gossypol as the daily loading dose and 35 or 43.75 mg as the week-ly maintenance dose could induce infertility in male volunteers without developing hypokalemia or irreversibility.(Asian J Androl 2000 Dec; 2: 283-287)
文摘This review provides an overview of the literature on aspects of reproductive endocrinology wherein Asian menmay differ from Caucasian, notably, prostatic nioplasm and the sensivity to pharmacological regimens of male contra-ception. Both genetic and environmental factors, such as nutrition, might be relevant. Asian men residing in Asia seemto be relatively protected from clinical prostatic nioplasm while the prevalence of preclinical prostatic nioplasm is notdifferent. Migration to an area with a higher prevalence reduces this difference but does not undo it. With regard toprostatic nioplasm the following factors have been considered as relevant in Asian men: 1) a reduction in 5α-reductaselevel, 2) decreased levels of androgenic ketosteroid precursors of 5α-reduced androgen metabolites, 3) the decreasedpresence of a P53 mutation, 4) a higher CAG-repeat length of the androgen receptor, 5) a possible higher level ofphysical activity, 6) differences in sexual activity. Furthermore, Asian men respond to a higher degree with azoosper-mia in response to contraceptive steroids. Possible explanations offered for the more pronounced response to contracep-tive steroids are: 1) differences in testicular structure and decreased spermatogenic potential, 2) an earlier and moremarked suppression in LH secretion by exogenous androgens. The differences may be due to genetical and/or environ-mental factors influencing the peripheral testosterone metabolism. Dietary factors such as the higher intake of phytoe-strogens in Asians might exert effects on 5α-reductase activity and/or on sex hormone binding globulin (SHBG) levels,thus having an impact on the biological efficay of circulating androgens. ( Asian J Androl 2000; 2: 13 - 20)
文摘Development of an ideal hormonal contraceptive for man has been the goal of several research workers during thepast few decades. Suppression of pituitary gonadotropic hormones, which in turn would inhibit spermatogenesis whilemaintaining normal libido and potentia has been the approach for a contraceptive agent. Intramuscularly administeredand orally active testosterone or testosterone in combination with progesterone have been shown to cause inhibition ofspermatogenesis resulting in azoospermia in normal men. Similarly testosterone has been used in combination with go-nadotropin releasing hormone antagonists and agonists to inhibit pituitary gonadotropic hormone release. Immunologicalapproach to neutralize the circulating levels of follicle stimulating hormone has also been shown to cause inhibition ofspermatogenesis. The available literature shows that testosterone causes reversible azoospermia without any significantside effects in Asian population effectively and appears to be a promising chemical for control of fertility in man.
文摘Effective regulation of human fertility has global consequences in terms of resource depletion, pollution and pover-ty. Current family planning services predominantly target a female clientele with few significant developments in malefertility regulation for over a century. The last two decades have witnessed a gathering interest, initially from the scien-tific community, and laterally from industry, in the development of safe, reliable, reversible methods of contraceptionfor men. This review summarises the methods of male fertility regulation which are currently available and critically ex-amines the published data on novel developments in male hormonal contraception which offer the potential of improvedcontraceptive choice for all in new millennium. (Asian J Androl 2000; 2: 3 - 12)
文摘Aim: The rationale and technique underlying a novel concept of non-invasive removal of an intravasal vas deferens poly-meric contraceptive drug to reverse drag injection-induced azoospermia are explained. Thus the conventional methods ofsurgical exploration to remove vas deferens plugs and intravasal injection of solvents to flush out contraceptive drugs are tobe replaced by steps which will be readily accepted by subjects. Methods: The approach is based upon the non-invasiveapplication of specific forces to various segments of the vas deferens so that non-sclerosing and non-tissue-adherent com-pounds, in particular styrene maleic anhydride (SMA) can be expelled. Forces are generated by palpation; percuta-neous electrical stimulation; vibration application; and percussion. The forces help to propel the intravasal polymer to-wards the ejaculatory duct for expulsion during ejaculation. All aspects of the total technique are clinically acceptable,simple, atraumatic, unlikely to cause pain and discomfort even without tranquilizers, local or general anaesthetics. Theprocedure may be repeated several times in different sittings spaced apart by about one week to achieve adequate plug ex-pulsion. Results: Model experiments demonstrated the feasibility of the concept. The polymer was nonadherent andcould be moved within the vas deferens by the application of specific forces. Sufficient removal was possible to enablespermatic fluid to be transported along a region previously occupied by the polymer. A corroborating subhuman primatestudy by an independent investigator has shown that the semen profile becomes normal following the reversal. Conclu-sion: Adoption of the new technique may provide a means of non surgical restoration of normal semen profile after a pe-riod of fertility control obtained by intravasal drag injection. (Asian J Androl 1999 Sep ; 1: 131 - 134)
