Treatment of GnRHa-implanted Senegalese sole (Solea senegalensis) with 11-ketoandrostenedione stimulates spermatogenesis and increases sperm motility

The effect of 11-ketoandrostenedione (OA) on plasma concentrations of sexual steroids and spermatogenesis of Senegalese sole (Solea senegalensis) implanted with gonadotropin-releasing hormone agonist (GnRHa) was investigated. Males were treated with saline (control) or with GnRHa implants (50 mug kg(-1)) in the presence or absence of OA (2 or 7 mg kg(-1)) during twenty eight days. Treatment with GnRHa alone slightly stimulated spermatogenesis and milt production with respect to controls, and this was associated with a transient elevation of plasma 11-ketotestosterone (11-KT) at day seven and an increase of 5beta-reduced metabolite(s) of 17,20beta-dihydroxy-pregn-4-en-3-one (17,20betaP) at day twenty eight. However, treatment with GnRHa+OA increased plasma concentrations of 11-KT and free+sulphated 5beta-reduced metabolites of 17,20betaP at days seven, fourteen and twenty one. After twenty eight days, the testis of GnRHa+OA-treated fish showed a lower number of spermatogonia B and spermatocytes I, and a higher number of spermatids, than fish treated with GnRHa alone. In addition, the motility of spermatozoa produced by GnRHa+OA males was enhanced by 2-fold with respect to controls or GnRHa males. These results suggest that treatment of Senegalese sole with GnRHa+OA stimulates spermatogenesis resulting in more motile sperm. Such effects could be mediated by an increased synthesis of 11-KT and/or 17,20betaP in the testis but further studies will be required to elucidate the specific mechanism involved.     

Immunohistochemical study of flotillin-1 in rat testis with ischemia/reperfusion injury

To investigate the involvement of flotillin-1 in acute experimental testicular torsion, we examined the expression and cellular localization of flotillin-1 and cathepsin D in the rat testis with ischemia/reperfusion (I/R) injury. Western blot analysis showed that the expression of flotillin-1 increased significantly 6h after I/R and that the level remained elevated for 48 h. Immunohistochemically, flotillin-1 was constitutively localized in some Sertoli cells, peritubular myoid cells, and interstitial cells in the normal testis. After I/R injury, Sertoli cells in the damaged tubules were intensely immunostained for flotillin-1 at 24 and 48 h after I/R. Flotillin-1 was also detected in some inflammatory cells in the interstitial space around damaged tubules. Furthermore, flotillin-1 was colocalized with cathepsin D, a lysosomal marker, in normal testis (mainly in Sertoli cells), and the colocalization was greater in Sertoli cells and macrophages in I/R injured testes. Therefore, we postulate that flotillin-1 immunoreactivity is increased in some Sertoli and inflammatory cells (especially in ED1-positive activated macrophages) in testicular torsion and that flotillin-1 in the injured testis associates with lysosomes in Sertoli cells and macrophages, activating subsequent signals in inflammatory macrophages and Sertoli cells after I/R.     

Localization and expression of selenoprotein S in the testis of <Emphasis Type="Italic">Psammomys obesus</Emphasis>

Summary Selenium is an essential trace element and selenoprotein S is a member of the selenoprotein family that has the non-standard amino acid selenocysteine incorporated into the polypeptide. Dietary selenium has been shown to play an important protective role in a number of diseases including cancer, immune function and the male reproductive system. In this study, we have observed high levels of selenoprotein S gene expression in the testis from Psammomys obesus. Real-time PCR and immunofluorescence demonstrate that selenoprotein S expression is low in testes from 4-week-old animals but increases significantly by 8 weeks of age and remains high until 17 weeks of age. Selenoprotein S protein is detected in primary spermatocytes, Leydig and Sertoli cells of 8, 12 and 17-week-old animals. These results suggest that selenoprotein S may play a role in spermatogenesis.     

Developmental origins of transgenerational sperm DNA methylation epimutations following ancestral DDT exposure

Epigenetic alterations in the germline can be triggered by a number of different environmental factors from diet to toxicants. These environmentally induced germline changes can promote the epigenetic transgenerational inheritance of disease and phenotypic variation. In previous studies, the pesticide DDT was shown to promote the transgenerational inheritance of sperm differential DNA methylation regions (DMRs), also called epimutations, which can in part mediate this epigenetic inheritance. In the current study, the developmental origins of the transgenerational DMRs during gametogenesis have been investigated. Male control and DDT lineage F3 generation rats were used to isolate embryonic day 16 (E16) prospermatogonia, postnatal day 10 (P10) spermatogonia, adult pachytene spermatocytes, round spermatids, caput epididymal spermatozoa, and caudal sperm. The DMRs between the control versus DDT lineage samples were determined at each developmental stage. The top 100 statistically significant DMRs at each stage were compared and the developmental origins of the caudal epididymal sperm DMRs were assessed. The chromosomal locations and genomic features of the different stage DMRs were analyzed. Although previous studies have demonstrated alterations in the DMRs of primordial germ cells (PGCs), the majority of the DMRs identified in the caudal sperm originated during the spermatogonia stages in the testis. Interestingly, a cascade of epigenetic alterations initiated in the PGCs is required to alter the epigenetic programming during spermatogenesis to obtain the sperm epigenetics involved in the epigenetic transgenerational inheritance phenomenon.     

吡氟酰草胺对大鼠睾丸的氧化损伤及机制研究

目的:评价吡氟酰草胺原药对大鼠睾丸的损伤效应及其机制,为完善该新型除草剂的安全性评价及防护措施提供实验依据。方法:分别给予雄性SD大鼠0、20(低)、100(中)和500 mg/kg/d(高)的吡氟酰草胺连续经口染毒90天,观察其一般毒性表现;测定血清中谷胱甘肽(GSH)、总抗氧化能力(T-AOC)、超氧化物歧化酶(SOD)的含量;评价大鼠的睾丸损伤,采用免疫印迹法检测睾丸组织中Cleaved-caspases 3、C-PRAR、FAS/FASL等蛋白的表达,并运用免疫组化法进行验证。结果:与对照大鼠相比,中、高剂量组的吡氟酰草胺能明显降低大鼠的体重增长及食物利用率(P0.05);血清SOD和T-AOC水平下降,以高剂量组SOD下降显著(P0.05),但GSH未见变化;染毒大鼠睾丸的生精小管空泡化严重、管腔内精原细胞显著减少;低、高剂量组大鼠睾丸组织中Cleaved-caspases 3、C-PRAR、FAS的表达显著增加;免疫组化也证实,低、高剂量组染毒大鼠生精小管中Cleaved-caspases 3阳性的细胞数显著增加(P0.05)。结论:吡氟酰草胺可引起大鼠睾丸中的抗氧化能力下降,睾丸可能是该除草剂潜在的靶器官,氧化应激通路可能参与了吡氟酰胺所致的雄性生殖毒性。     

高原鼢鼠(Myospalax baileyi)尿道球腺的初步研究

雄性哺乳动物尿道球腺(bulbo-urethral gland)(以下简称B.U.腺)的研究,早已引起人们注意,曾先后对多种家畜(Bharagwaj等,1962;Ali等,1978)、大鼠(Heller1932;Geuze等,1976,1978)、小鼠(Hall,1936)、豚鼠(Nittinger,1973)以及其它野生鼠类,如仓鼠(转引自Geuze等,1978)、穴兔(Dahlback 等,1981)和4种欧洲睡鼠(Hrabe vit,1968)等动物的B.U.腺进行了研究。其内容多着重于组织化学、超微结构以及与性活动的关系。     

The expression pattern of a mouse doublesex-related gene is consistent with a role in gonadal differentiation

The signal for somatic sex determination in mammals, Caenorhabditis elegans and Drosophila melanogaster is chromosomal, but the overall mechanisms do not appear to be conserved between the phyla. However it has been found quite recently that the C. elegans sex-determining gene Mab-3 contains a domain highly homologous to the Drosophila sex-determining gene doublesex (dsx) and shares a similar role. These data suggest that at least some aspects of the regulation of sex determination might be conserved. In humans, a doublesex-related gene (DMRT1) was identified at less than 30 kb from the critical region for sex reversal on chromosome 9p24 (TD9). In order to get insights into the role of DMRT1 in sex determination/differentiation, we have isolated DMRT1 mouse homologue (Dmrt1) and analysed its expression pattern. The gene is expressed in the genital ridges of both sexes during the sex-determining switch and it shows male/female dimorphism at late stages of sex differentiation.     

Ultrastructural and immunohistochemical studies on steroid-secreting cells of the testis and ovary of normal and 3-methylcholanthrene-treated mice

Summary The testis and ovary of normal and 3-methylcholanthrene-treated mice were studied ultrastructurally and immunohistochemically in order to learn whether steroid-secreting cells of the gonads are involved in drug metabolism. The steroid-secreting cells, i.e., Leydig cells of the testis, and theca interna cells, interstitial gland cells, and corpus luteum cells of the ovary of 3-methylcholanthrene-treated mice, show a strong positive reaction to the antiserum against, hepatic microsomal cytochrome P-450, of liver which is the terminal oxidase of the drug-metabolizing enzyme complex. In addition, it was found that elements of smooth endoplasmic reticulum (SER) in drug-treated mice become well developed as compared with those in control animals. These findings indicate that the steroid secreting cells in testis as well as ovary are involved in the metabolism of both endogenous and exogenous chemical compounds.This study was supported by grants from the Ministry of Education, Science and Culture, Japan     

Inhibition of testosterone biosynthesis by ethanol: relation to the pregnenolone-to-testosterone pathway

The concentrations of metabolites in the pregnenolone → testosterone pathway were determined in freezestopped testes in control rats and during ethanol intoxication (2 h after injection of 1.5 $\text{g ethanol}\text{kg}$ body wt). Ethanol lowered the mean testicular concentrations of testosterone (by 63–74%), androstenedione (49–81%), 17-hydroxyprogesterone (60–76%), progesterone (29–67%) and pregnenolone (12–25%). 4-Methylpyrazole had no effect on the ethanol-induced changes. The present results reveal no inhibition at the 17-hydroxyprogesterone → androstenedione → testosterone steps, but do not exclude inhibition before the step yielding pregnenolone and at the pregnenolone → progesterone → 17-hydroxyprogesterone steps.