Flutamide induces alterations in the cell-cell junction ultrastructure and reduces the expression of Cx43 at the blood-testis barrier with no disturbance in the rat seminiferous tubule morphology

BACKGROUND: Present study was designed to establish a causal connection between changes in the cell-cell junction protein expression at the blood-testis barrier and alterations in the adult rat testis histology following an anti-androgen flutamide exposure. Particular emphasis was placed on the basal ectoplasmic specialization (ES) in the seminiferous epithelium and expression of gap junction protein, connexin 43 (Cx43). METHODS: Flutamide (50 mg/kg body weight) was administered to male rats daily from 82 to 88 postnatal day. Testes from 90-day-old control and flutamide-exposed rats were used for all analyses. Testis morphology was analyzed using light and electron microscopy. Gene and protein expressions were analyzed by real-time RT-PCR and Western blotting, respectively, protein distribution by immunohistochemistry, and steroid hormone concentrations by radioimmunoassay. RESULTS: Seminiferous epithelium of both groups of rats displayed normal histology without any loss of germ cells. In accord, no difference in the apoptosis and proliferation level was found between control and treated groups. As shown by examination of semi-thin and ultrathin sections, cell surface occupied by the basal ES connecting neighboring Sertoli cells and the number of gap and tight junctions coexisting with the basal ES were apparently reduced in flutamide-treated rats. Moreover, the appearance of unconventional circular ES suggests enhanced internalization and degradation of the basal ES. These changes were accompanied by decreased Cx43 and ZO-1 expression (p < 0.01) and a loss of linear distribution of these proteins at the region of the blood-testis barrier. On the other hand, Cx43 expression in the interstitial tissue of flutamide-treated rats increased (p < 0.01), which could be associated with Leydig cell hypertrophy. Concomitantly, both intratesticular testosterone and estradiol concentrations were elevated (p < 0.01), but testosterone to estradiol ratio decreased significantly (p < 0.05) in flutamide-treated rats compared to the controls. CONCLUSIONS: Short-term treatment with flutamide applied to adult rats exerts its primary effect on the basal ES, coexisting junctional complexes and their constituent proteins Cx43 and ZO-1, without any apparent morphological alterations in the seminiferous epithelium. In the interstitial compartment, however, short-term exposure leads to both histological and functional changes of the Leydig cells

Aromatase - function and role in the male gonad of selected mammals.

Aromataza jest enzymem katalizującym przemianę androgenów w estrogeny w procesie zwanym aromatyzacją. W poniższej pracy przedstawiono mechanizm działania, budowę i lokalizację aromatazy w gonadzie męskiej u wybranych gatunków ssaków. Aromatyzacja jest procesem złożonym, wieloetapowym i nieodwracalnym. W pracy został zawarty opis specyfik przemian prowadzących do powstania estrogenowego produktu z androgenowego substratu. Opisano również strukturę genu kodującego aromatazę, oraz budowę enzymatycznego kompleksu aromatazy zlokalizowanego w gładkiej siateczce śródplazmatycznej licznych tkanek. W gonadzie męskiej umiejscowienie ekspresji tego enzymu zależne jest od gatunku, wieku osobnika, oraz warunków życia i rozwoju. W pracy porównano dokładną lokalizację tego enzymu w jądrach wybranych ssaków. Zwrócono również uwagę na skutki niedoboru i nadmiaru aromatazy.Aromatase is the enzyme that catalyses the synthesis of estrogens from androgens. The aim of this work is to show the mechanism of aromatase, structure and aromatase expression in the mammalian male gonad.Aromatization is a complicated, irreversible and multistep process. This work contains description of specific transformation androgen substrates to estrogen products. Moreover, there is a description of the aromatase gene and the structure of aromatase enzyme complex which is localized in the smooth endoplasmic reticulum in various tissues. In the male gonad expression of this enzyme is age- and species- dependent. This work is focused on differential localization of aromatase in the male gonad of various mammals. Moreover, consequences of deficiency or excess of aromatase were also described