RESUMO
Previous results obtained with a model system of human epididymal tubules maintained in organ culture suggested that androgenic stimulation of this tissue resulted in responses similar to those obtained in epididymides of experimental animals under physiological conditions, as well as in other human androgen-dependent tissues. In this instance we have explored the possible influence of androgens on the activity of the androgen-converting enzymes 5 alpha-reductase and 17 beta-dehydrogenase. Activity of the former enzyme increases significantly during the culture period but no differences were found among the cultured groups, regardless of the addition of androgen. On the other hand, the activity of 17 beta-dehydrogenase was unchanged in all the experimental conditions tested. The co-culture of the tissue with explants of human testis was without effect. More than 85% of the activity of both enzymes was found localized in a fraction enriched in epithelial cells. Histological observation of the cultured tissues showed a marked disorganization of the pseudostratified epithelium in the absence of androgen while the inclusion of DHT in the media partially prevented these changes. We conclude that, under the conditions employed in these experiments, the activity of the enzymes studied is not influenced by androgens.
Assuntos
17-Hidroxiesteroide Desidrogenases/metabolismo , 3-Oxo-5-alfa-Esteroide 4-Desidrogenase/metabolismo , Androgênios/farmacologia , Epididimo/enzimologia , Idoso , Androgênios/metabolismo , Di-Hidrotestosterona/metabolismo , Epididimo/citologia , Células Epiteliais , Humanos , Masculino , Pessoa de Meia-Idade , Técnicas de Cultura de Órgãos , Testículo/citologiaRESUMO
Some preliminary speculations about the possible participation of epididymal antigens in sperm function may be supported by the above data. On the one hand, the reduction in the amount of antigens and their abnormal localization on spermatozoa from infertile patients may be coincident with our view about participation of epididymal antigens in the development of zona pellucida binding ability and fertilizing capacity by spermatozoa during maturation. This hypothesis is derived from experiments showing that immature hamster spermatozoa gain their ability to recognize and bind to zona pellucida and to penetrate homologous oocytes when exposed to preparations enriched in androgen-dependent epididymal secretory proteins or preincubated in conditions that favor their interaction with these proteins. Supporting our viewpoint for such a role in humans is evidence showing the progressive development of the ability to interact with hamster denuded oocytes as human spermatozoa pass along the epididymis. On the other hand, the apparent correlation between the loss of epididymal antigens during capacitation and the increased fertilization of human oocytes in vitro may be reminiscent of the removal of a decapacitation or acrosome stabilizing factor known to occur in many species and that must be removed prior to fertilization. Pending further understanding of their physiological role, the androgen-dependent epididymal proteins may become a useful marker of epididymal function and/or of sperm capacitation in humans. Within this context, we wish to stress the potential value of the model system that we have developed for the study of human epididymal physiology.