ncRNAs are involved in numerous biological processes by regulating gene expression and cell stability. Studies have shown that ncRNAs also contribute to spermatogenesis. Leydig cells (LCs) and Sertoli cells (SCs) are somatic cells of the testis that support spermatogenesis and are vital to male fertility. In this review, we summarized the findings from studies on ncRNAs in SCs and LCs. In SCs, ncRNAs play key roles in phagocytosis, immunoprotection and development of SCs. In LCs, ncRNAs are involved in steroidogenesis, in particular production of testosterone as well as development of LCs. Here, we discuss the possible target genes and functions of ncRNAs in both types of cells. These ncRNAs regulate the expression of target genes or mRNA coding sequence regions, resulting in a chain reaction that influences cell function. In addition, microRNAs, lncRNAs, piRNA-like RNAs (pilRNAs) and natural antisense transcripts (NATs) are discussed in this review. In summary, we suggest that these ncRNAs might act in coordination to control spermatogenesis and maintain the environmental homeostasis of the testis.

Traditionally, male pigs are surgically castrated without anaesthesia to avoid later occurrence of the sex odour of androstenone in the carcass. Active immunization against gonadotropin-releasing hormone (GnRH) is a painless alternative which inhibits LH and thus steroidogenesis in the Leydig cells. In a preceding study we clarified the return of Leydig cell function after the last dose of antigen by measuring hormones, and found a considerable variation (10 to 24 weeks) till return of their function (testosterone ⩾ 0.5 ng/ml blood plasma). The present paper analyses histological data on testes characteristics of the same six boars at an age of 52 weeks (26 weeks after last immunization). Data were compared to another four boars which were not immunized but slaughtered at the same age. Testis weight was related to the concentration of testosterone in blood. In boars, that first returned to testicular function, testis weight even exceeded those in controls probably due to rebound phenomena. Differences in testis weight were mainly due to differences of Leydig cell content of cytoplasm, and less to the size of nuclei. Additionally, the height of seminiferous epithelium was slightly dependent on testosterone concentrations and contributed moderately to differences in testis weight. Altogether, normalization of testicular function, even after return to steroidogenesis, requires another 13 weeks.

Testicular cell-to-cell interactions play a key role in the regulation of spermatogenesis. In the testis, cell contacts are mediated through several mechanisms, including paracrine and direct contacts depending on gap junctional pathways. Gap junctions require connexin (Cx) channels and connexin-43 (Cx43) represent the most abundant Cx found in mammalian testis. Little is known about Cx expression in non-mammalian testis. Here we report the partial cloning of a Cx43 transcript of 381 bp from Rana esculenta testis. We also demonstrate that, in the frog testis, Cx43 transcript and protein show a parallel temporal and spatial pattern of expression throughout the reproductive annual cycle, with higher levels from September to January (when spermatogenesis is at a maximum level). In situ hybridization, carried out on testis collected in October, indicated that Leydig cells (LC) and Sertoli cells express Cx43 transcript, while the hybridization signal was less intense in germ cells. To obtain more information on Cx43 expression in the frog testis, we have used ethane-dimethane sulphonate (EDS), a toxin that specifically destroys LC. RT-PCR analysis shows a progressive decrease in Cx43 expression in EDS-treated testis from day 1 to day 4 after the injection, associated with LC destruction. Moreover, Cx43 expression returns to normal on day 28, when a new population of LC reappear in the interstitium, indicating that Cx43 is mainly expressed by LC. Taken together our data provide evidence that Cx43 is present in the frog testis with an important role in spermatogenesis.

The amphibian testis is a useful model because of its zonal organisation in lobules, distributed along the cephalocaudal axis, each containing a unique germ cell type. Sperm empty lobules form the so-called glandular tissue at the posterior region of the gonad. Androgen production is limited to the cells of the interstitial tissue surrounding lobules with spermatozoa bundles and to the cells of the glandular tissue. In this work, we have studied the distribution of terminal carbohydrate moieties of N- and O-linked oligosaccharides in the interstitial and glandular tissue of the Pleurodeles waltl testis, by means of 14 lectins combined with chemical and enzymatic deglycosylation pretreatment. Some differences in glycan composition between the interstitial and the glandular tissue have been detected. Thus in both tissues, N-linked oligosaccharides contained mannose, Gal(β1,4)GlcNAc, and Neu5Ac(α2,3)Gal(β1,4)GlcNAc, while O-linked oligosaccharides contained Con A-positive mannose, Gal(β1,3)GalNAc, Gal(β1,4)GlcNAc, Neu5Ac(α2,3)Gal(β1,4)GlcNAc, and WGA-positive GlcNAc. Fucose was also detected in both tissues. However, GlcNAc on N-linked oligosaccharides and GalNAc and Neu5Ac(α2,6)Gal/GalNAc on both N- and O-linked oligosaccharides were found only in the interstitial tissue. As glandular tissue cells arise from the innermost cells of interstitial tissue that surround lobules, the differences in the glycan composition of interstitial and glandular tissue shown in this work may be related to the start of androgen synthesis when steroid hormone (SH)-secreting cells develop.