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Publication
Contraceção masculina: a pílula também é para homens
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Abstract(s)
A contraceção como ato deliberado e consciente da decisão de não ter filhos é uma temática relevante na sociedade e é uma ferramenta no combate à escassez de recursos. Todavia, com exceção do preservativo, as opções disponíveis são afetas quase exclusivamente à mulher.
Nesta dissertação, é apresentado o state of the art no que toca à farmacologia da contraceção masculina hormonal e não hormonal. Dos fármacos hormonais, que interferem com o eixo hipotálamo-hipófise, inibindo assim a espermatogénese, destacam-se os derivados de testosterona (acetato de segesterona, undecanoato de dimetandrolona e o 11β-metil-19-nortestosterona), que apesar do seu efeito contracetivo eficaz, apresentam efeitos adversos pouco aceitáveis: diminuição da líbido e aumento de peso. Alternativas fitoterapêuticas, como o gossipol e o triptonido, exibem efeito contracetivo, contudo são necessários estudos adicionais devido às dificuldades de formulação e de reversibilidade do efeito. Fármacos desenvolvidos para inibir canais iónicos específicos dos espermatozoides, como o CatSper e SLO3, mostraram resultados promissores como contracetivos masculinos por inviabilizarem a mobilidade dos espermatozoides. Antagonistas dos recetores dos ácidos retinóicos, diminuem a expressão de proteínas responsáveis pela regulação e manutenção do ciclo espermatogénico, assim como inibidores de uma proteína específica do testículo, associada à remodelação da cromatina em espermatócitos e espermátides, mostraram evidências na diminuição da mobilidade e produção de espermatozoides. Apesar disto, apenas o RISUG®, um polímero oclusivo inoculável no canal deferente, o qual provoca a inviabilização dos espermatozoides antes da ejaculação, está perto de se tornar comercializável.
Nesta dissertação apresentam-se ainda os resultados obtidos num inquérito informal, no qual participaram 379 indivíduos de ambos os sexos, com o objetivo de avaliar o nível de aceitação desta classe de fármacos pela população, o qual se mostrou positivo.
Contraception as a deliberate and conscious act of deciding not to have children is a relevant issue in society and is an important tool to avoid the scarcity of resources. However, apart from condoms, the available options are almost exclusively for women. This dissertation presents the state of the art of hormonal and non-hormonal pharmacological solutions for male contraception. Among the hormonal drugs, which interfere with the hypothalamic-pituitary axis, inhibiting spermatogenesis, testosterone derivatives (segesterone acetate, dimethandrolone undecanoate and 11β-methyl-19-nortestosterone) showed promising effectiveness as contraceptive, however they present unacceptable side effects such as decreased libido and weight gain. Fitoterapeutic non-hormonal alternatives, such as gossypol and triptonide, exhibit contraceptive effect, but require further studying due to formulation challenges and irreversible effects. Drugs targeting ion channels exclusive to sperm, such as CatSper and SLO3, showed contraceptive effect by affecting sperm mobility. Retinoic acid receptor antagonist, reduce the expression of proteins responsible for regulating and maintaining the spermatogenesis. Likewise, inhibitors of a testis-specific protein, which are associated with chromatin remodeling in spermatocytes and spermatids, have shown good results in reducing sperm mobility and production. However, only RISUG®, a vas deferens polymer causing sperm unviability, is nearing commercialization among male contraceptive options. The present work also includes the results obtained from an informal survey, in which 379 individuals of both sexes participated, with the aim of evaluating the level of acceptance of this class of drugs by the population, which proved to be positive.
Contraception as a deliberate and conscious act of deciding not to have children is a relevant issue in society and is an important tool to avoid the scarcity of resources. However, apart from condoms, the available options are almost exclusively for women. This dissertation presents the state of the art of hormonal and non-hormonal pharmacological solutions for male contraception. Among the hormonal drugs, which interfere with the hypothalamic-pituitary axis, inhibiting spermatogenesis, testosterone derivatives (segesterone acetate, dimethandrolone undecanoate and 11β-methyl-19-nortestosterone) showed promising effectiveness as contraceptive, however they present unacceptable side effects such as decreased libido and weight gain. Fitoterapeutic non-hormonal alternatives, such as gossypol and triptonide, exhibit contraceptive effect, but require further studying due to formulation challenges and irreversible effects. Drugs targeting ion channels exclusive to sperm, such as CatSper and SLO3, showed contraceptive effect by affecting sperm mobility. Retinoic acid receptor antagonist, reduce the expression of proteins responsible for regulating and maintaining the spermatogenesis. Likewise, inhibitors of a testis-specific protein, which are associated with chromatin remodeling in spermatocytes and spermatids, have shown good results in reducing sperm mobility and production. However, only RISUG®, a vas deferens polymer causing sperm unviability, is nearing commercialization among male contraceptive options. The present work also includes the results obtained from an informal survey, in which 379 individuals of both sexes participated, with the aim of evaluating the level of acceptance of this class of drugs by the population, which proved to be positive.
Description
Keywords
Espermatogénese Contraceção Contraceção farmacológica masculina Fármacos hormonais Fármacos não hormonais