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PubMed1995

Ultrastructural and radioautographic studies on DNA synthesis in Leydig cells on aging mouse testis.

A morphological observation and a radioautographic study were carried out to detect the ultrastructure and aging changes of DNA synthesis of the Leydig cells, whose structure has been observed and the area of the lipid droplets in the cytoplasm calculated. The observation by electron microscopy showed that Leydig cells contained abundant mitochondria and endoplasmic reticulum and that the area of the lipids in the cytoplasm changed with aging. Only little lipid droplets were found in embryonic and early postnatal stages, but they increased from postnatal two weeks onwards and no significant differences were found from 9 months to 21 months. The DNA synthesis in these cells was not vigorous at embryonic day 19, explored by light microscopic radioautography 1 hr. following a single injection of 3H-thymidine. The labeling index increased slightly before six months of age and reached its peak at 9 months. There was no significant difference found in the number of labelled cells from that time on. A relatively high level was maintained at adult and senescent periods. Our results demonstrate that the generation of the Leydig cells contained plentiful lipid droplets was vigorous at adult and senescence.

Aging↗
PubMed1993

Multiple levels of regulation exist for expression of the Hoxa-4 (Hox-1.4) gene in the mouse testis.

The experiments presented in this study show that the testis-specific expression of the murine Hoxa-4 (formerly Hox-1.4) gene is likely to be achieved through a variety of regulatory mechanisms operating on several levels. S1 mapping analysis suggested the possibility of multiple testicular transcripts arising from alternative splicing events. Analysis of cDNA and genomic sequences revealed the presence of two polyadenylation signals: the canonical AATAAA and further 3', an ATTAAA. Primer extension analysis to determine the start site of the testicular transcripts and nuclear run-on analysis suggested the use of a more upstream promoter than the one previously identified. The nuclear run-on analysis further suggested that Hoxa-4 is under posttranscriptional control. RNase H analysis showed that the size difference between the two testicular Hoxa-4 transcripts of 1.35 and 1.45 kb was due to a postmeiotic increase in poly(A) tail length. Only a proportion of the Hoxa-4 mRNA in germ cells was found to be associated with polysomes, suggesting that translational regulation may also operate as a means of control of Hoxa-4 expression in this adult lineage.

Alternative Splicing↗
PubMed1997

Effects of in utero exposure to nonsteroidal estrogens on mouse testis.

Male mice exposed in utero to alpha-zearalanol (zeranol) or diethylstilbestrol (DES) were analyzed postnatally to evaluate the possible changes on their testicular morphology as part of an examination of the effects of transplacental exposure to non-steroidal estrogens on sensitive tissues. Pregnant NMRI mice were injected subcutaneously with ethyl oleate (0.1 mL) alone (negative control) or with 150 micrograms/kg of body weight of zeranol or DES (positive control) on days 9 and 10 of gestation. Experimental and control male offspring were euthanized at days 45 (n = 47), 90 (n = 44), 180 (n = 40) and 365 (n = 26) after birth and their gonads were examined by light and electron microscopy. The results suggested that prenatal zeranol or DES exposure induced more severe and earlier (at 45 d) testicular abnormalities than in negative control (at 6 mo). These age-related alterations were characterized by regressive changes in the germinal epithelium and Sertoli's cells as well as foci of Leydig's cells around atrophied seminiferous tubules and dysplasia of the rete testis epithelium. On the contrary, the presence of Leydig's cells with immature morphology and their arrangement in sheet could be attributable exclusively to estrogen treatment. The presence of no neoplasm was confirmed.

Analysis of Variance↗
PubMedDate not supplied

Round spermatids from prepubertal mouse testis can develop into normal offspring.

We investigated fertilization and embryo development after intracytoplasmic injection of round spermatids collected from mice before puberty. The rates of normal fertilization, blastocyst formation, and development into live offspring were examined. The injection of oocytes with round spermatids from mature or prepubertal males resulted in similar rates of normal fertilization and embryo development. The rates of the development to term of two-cell embryos were also similar, regardless of the origin of the round spermatids injected. This finding suggests that round spermatids from the prepubertal testis already have the ability to fertilize normally and to allow normal embryo development.

Animals↗
PubMedDate not supplied

[Kinetics of metabolism and mechanisms of formation of absorbed doses in the mouse testis from incorporated Cs-137].

The process of accumulation of absorbed doses from incorporated 137Cs in the body and gonads of male mice was investigated in our experiments. The radionuclide accumulated in gonads has very long time of excretion, and as result the radionuclide can be treated as long lasting and permanent source of alpha- and beta-radiation in gonads. The rates of total exposed doses in gonads were in 2.0-3.0 times higher then the average total exposed dose in hole body.

Animals↗
PubMed2006

Diazepam administration prevents testosterone decrease and lipofuscin accumulation in testis of mouse exposed to chronic noise stress.

Lipofuscin is an autofluorescent and undegradable material, which accumulates in tissues during ageing and under different types of stress. Among these, oxidative stress represents a major trigger for lipofuscin formation. However, prolonged noise exposure is also an effective stressful stimuli. Diazepam may inhibit lipofuscinogenesis in liver and prevent the noise-induced reduction of the steroidogenesis in the adrenal gland. The aim of the study was to ascertain whether chronic noise exposure causes lipofuscin accumulation in mouse testis, and to evaluate the effects of diazepam administration. Eight-week old mice were either exposed for 6 weeks (6 h day(-1)) to white-noise (group A), or received diazepam (3 mg kg(-1), i.p.) before noise exposures (group B), while a further group was used as control (group C). Light fluorescence and transmission electron microscopy revealed lipofuscin in large amounts in the Leydig cells in mice of group A, which concomitantly had low serum testosterone levels; pre-treatment with diazepam occluded both effects. The present study indicates that: (i) chronic noise exposure causes lipofuscin accumulation at the level of the Leydig cells and a decrease in testosterone; (ii) all these effects are suppressed by pre-treatment with diazepam. As the Leydig cells represent the only cellular type of the interstitial testicular tissue having peripheral benzodiazepine receptors, these results could be explained by the capacity of the peripheral benzodiazepine receptors to prevent reactive oxygen species damage and to increase the resistance of these cells to oxidative stress.

Animals↗
PubMed2003

Expression of p63 in the testis of mouse embryos.

Apoptosis of testicular germ cells during fetal development is regulated by both p53-dependent and independent mechanisms. However, its precise mechanisms are largely unknown. A member of p53 gene family, p63, is required for p53-dependent apoptosis and can induce apoptosis in the absence of p53 through the activation of p53-target genes. In this study, we examined the expression pattern of p63 in the mouse testis from embryonic day (E) 13.5 to E18.5 to clarify their possible role in the regulation of germ cell apoptosis. Immunostaining for p63 was found in the nucleus of germ cells at E13.5, and continuously observed until E18.5. The RT-PCR using specific primers for two p63 isotypes, those containing the transactivation domain and others not, showed that both transcripts were expressed in the fetal gonads. Possible roles of p63 in the embryonic testes were discussed.

Animals↗
PubMed1991

Evidence for the requirement of proteolysis in LH stimulated cyclic AMP production and steroidogenesis in Leydig cells.

We have investigated the effect of protease activity on cyclic AMP production and steroidogenesis in rat testis, mouse testis and mouse tumour Leydig (MA10) cells. LH-, dibutyryl cyclic AMP-, and forskolin-stimulated steroidogenesis, but not 22R(OH) cholesterol conversion to pregnenolone, was inhibited by protease inhibitors. In mouse Leydig cells, LH but not forskolin or cholera toxin stimulated cyclic AMP production was inhibited by protease inhibitors. These results suggest that steroidogenesis in Leydig cells requires proteolysis before the conversion of cholesterol to pregnenolone. In the mouse but not rat Leydig cells, LH-stimulated cyclic AMP production is also dependent on proteolysis.

Animals↗
PubMed1994

Identification and characterization of the developmentally regulated pattern of expression in the testis of a mouse gene exhibiting similarity to the family of phosphodiesterases.

A cDNA for a rat brain phosphodiesterase (PDE) was used to screen a mouse testis library to identify the murine PDEs which are expressed in this tissue. A clone of 981 bp, p4-6, was isolated and shown to exhibit limited identity at the amino acid level to the rat brain PDE (20%). The putative protein encoded by clone p4-6 also contains multiple potential modification sites, for phosphorylation, myristylation, and glycosylation, many of which are located at positions similar to those found for rat brain PDE. The gene identified by p4-6 yields 3 transcripts, an abundant 1.9 kb transcript, and less abundant transcripts of 3.8 and 6.7 kb. Of the nine tissues examined in this study, the expression of the corresponding gene was limited to the adult mouse testis. Furthermore, the expression in the testis was most abundant in the germ cell lineage, although low levels were detected in somatic cells of the testis as well. Analysis of RNA from testes at different stages of development suggested that the p4-6 gene is most abundantly expressed in germ cells that have completed the meiotic divisions.

Amino Acid Sequence↗
PubMed1988

Nerve growth factor mRNA and protein in the testis and epididymis of mouse and rat.

In situ hybridization using beta-nerve growth factor (NGF) DNA probes was used to demonstrate NGF mRNA in spermatocytes and early spermatids of adult mouse. NGF mRNA-containing cells were also identified in the epithelium of convoluted ducts in mouse corpus epididymidis. Blot-hybridization analysis of RNA prepared from mouse testis and epididymis as well as from rat epididymis confirmed the presence of a 1.3-kilobase (kb) NGF mRNA in these tissues. In the rat testis, however, only a 1.5-kb NGF mRNA was found, corresponding in size to a minor NGF mRNA detected in the rat brain, heart, and epididymis. By using affinity-purified anti-NGF antibodies, NGF-like immunoreactivity was observed in germ cells of rat and mouse testis and in the lumen of epididymis. Extracts of both mouse epididymis and testis stimulated fiber outgrowth in cultured sympathetic ganglia, and the effect was blocked by antibodies to mouse NGF. A two-site enzyme immunoassay showed the presence of 10 and 70 ng of NGF per g of tissue in the mouse testis and epididymis, respectively. Furthermore, RNA blot analysis showed the presence of mRNA for the NGF receptor in mouse testis. These results suggest a nonneurotrophic role for NGF in the male reproductive system, possibly in survival maturation and/or motility of spermatozoa.

Animals↗