An acute exposure to glyphosate-based herbicide alters aromatase levels in testis and sperm nuclear quality.

Roundup is the major pesticide used in agriculture worldwide; it is a glyphosate-based herbicide. Its molecular effects are studied following an acute exposure (0.5%) of fifteen 60-day-old male rats during an 8-day period.

Aromatase, oestrogens and human male reproduction.

In most mammalian species aromatase is encoded by a single gene (Cyp19), which contains 18 exons, nine of them being translated. In man, the presence of a biologically active aromatase and oestrogen receptors (ERalpha and ERbeta) has been reported in Leydig cells, and also in immature germ cells and ejaculated spermatozoa. Concerning aromatase, the amount of transcript and enzymatic activity are decreased in immotile compared with motile sperm.

Mammalian sperm quality and aromatase expression.

In most mammalian species the aromatase is encoded by a single gene (cyp19), which contains 18 exons, 9 of them being translated. In adult rats, together with Leydig cells germ cells represent an additional source of estrogens. The amount of P450arom transcript is threefold higher in pachytene spermatocytes compared to younger cells (spermatogonia-preleptotene spermatocyte) or round spermatids; conversely, aromatase activity is more intense in haploid cells.

Estrogens: a new player in spermatogenesis.

The mammalian testis serves two main functions: production of spermatozoa and synthesis of steroids; among them, estrogens are the end products obtained from the irreversible transformation of androgens by aromatase. The aromatase is encoded by a single gene (cyp19) in humans which contains 18 exons, 9 of them being translated. In rat the aromatase activity is mainly located in Sertoli cells of immature animals and then in Leydig cells of adults.

Transcripts of aromatase and estrogen receptors and significance of other RNAs in human spermatozoa.

The existence of a complex population of mRNAs in human sperm is well documented but their role is not completely elucidated. Evidence for a latent transcriptional capacity and/or a potential translation de novo in mature spermatozoa from fertile men has been provided and is helpful in understanding the final steps of sperm maturation (capacitation and/or the acrosome reaction). Spermatogenesis is controlled by gonadotrophins and testosterone, their effects are modulated by locally-produced factors that include estrogens derived from the irreversible transformation of androgens by aromatase.

Relationship between chromatin organization, mRNAs profile and human male gamete quality.

Spermiogenesis is a complex process leading to the formation of motile spermatozoa characterized by a highly stable chromatin compaction that transfers the paternal genome into the oocyte. It is commonly held that these haploid cells are devoid of transcriptional and translational activities and that the transcripts represent remnants of stored mRNAs. Recently, the chromatin organization of mature spermatozoa has been revisited as a double nucleoprotamine-nucleohistone structure possessing less-condensed regions sensitive to nuclease activity, which could be implicated in the expression of genes involved in the early embryo development.

Expression of aromatase in human ejaculated spermatozoa: a putative marker of motility.

Cytochrome p450 aromatase (p450arom) is a key enzyme responsible for the irreversible transformation of androgens into estrogens. In the present study, we have analysed the ability of human ejaculated spermatozoa to produce estrogens and for that purpose we have looked for the expression of specific aromatase transcript and protein. We have confirmed the presence of p450arom transcript in all normospermic purified samples by nested PCR.

[Testicular aromatase].

The cytochrome P450 aromatase (P450arom) is the terminal enzyme involved in the irreversible transformation of androgens into estrogens. The P450arom plays a role in development, reproduction, sexual differentiation and behaviour, but also in bone and lipid metabolisms, brain functions and diseases such as breast and testicular tumors. Besides testicular somatic cells, where the aromatase gene is expressed via promoter II and I.

Reproductive system: aromatase and estrogens.

The cytochrome P450 aromatase (P450arom) is the terminal enzyme responsible for the formation of estrogens from androgens. In the rat testis we have immunolocalized the P450arom not only in Leydig cells but also in germ cells and especially in elongated spermatids. Related to the stage of germ cell maturation, we have shown that the level of P450arom transcripts decreases, it is much more abundant in pachytene spermatocytes (PS) than in mature germ cells whereas the aromatase activity is two- to fourfold greater in spermatozoa when compared to younger germ cell preparations.