Differential expression of mRNA aromatase in ejaculated spermatozoa from infertile men in relation to either asthenozoospermia or teratozoospermia.

Oestrogen biosynthesis in ejaculated spermatozoa is an autonomous process, which may influence sperm functions. The purpose of this study was to evaluate the relationship between the expression of aromatase, sperm quality and seminal neutral α-glucosidase marker in semen of Tunisian infertile men: asthenozoospermia (A; n = 16), teratozoospermia (T; n = 12) and asthenoteratozoospermia (AT; n = 11) in comparison with 18 normozoospermic ones. Aromatase mRNA levels estimated by real-time PCR were reduced in groups T (52%) and AT (67%) compared to controls and inversely correlated with the percentage of normal forms.

Disruption of nongenomic testosterone signaling in a model of spinal and bulbar muscular atrophy.

As one of the nine hereditary neurodegenerative polyQ disorders, spinal and bulbar muscular atrophy (SBMA) results from a polyQ tract expansion in androgen receptor (AR). Although protein aggregates are the pathological hallmark of many neurodegenerative diseases, their direct role in the neurodegeneration is more and more questioned. To determine the early molecular mechanisms causing motor neuron degeneration in SBMA, we established an in vitro system based on the tetracycline-inducible expression of normal (AR20Q), the mutated, 51 glutamine-extended (AR51Q), or polyQ-deleted (AR0Q) AR in NSC34, a motor neuron-like cell line lacking endogenous AR.

Estrogen, a female hormone involved in spermatogenesis.

In mammalian testes, aromatase irreversibly converts androgens (C19 steroid) into estrogens (C18) and is present in the endoplasmic reticulum of numerous tissues. In purified adult rat germ cells (pachytene spermatocytes and round spermatids) we have shown the presence of a functional aromatase (transcript, protein and biological activity) and the estrogen production is roughly identical to that of Leydig cells. In addition, transcripts of aromatase varied according to the germ cell type and the stages of seminiferous epithelium in an adult rat.

Estrogens in male germ cells.

The biosynthesis of steroids and the production of spermatozoa are two major functions of the mammalian testis which are tightly controlled by gonadotropins and numerous locally produced factors. Among these are the estrogens that are produced within the seminiferous epithelium via the irreversible transformation of androgens (C19) into estrogens (C18) by aromatase. We have recently reported that male germ cells are the new source of estrogens in the testis.

Role of estrogens in spermatogenesis.

Aromatase converts irreversibly androgens into estrogens and is present in the endoplasmic reticulum of various cells of mammalian testes ; at least in rodents, all testicular cells except peritubular cells express aromatase. In testis, high affinity estrogen receptors, ERalpha and/or ERbeta, together with a membrane rapid effect recently described, mediate the effects of estrogens. From the experimental models, in vitro studies and data collected in patients, it is now demonstrated that estrogens play an important role in the testis of vertebrates.