STX2 is a causative gene for nonobstructive azoospermia.

STX2 encodes a sulfoglycolipid transporter. Although Stx2 nullizygosity is known to cause spermatogenic failure in mice, STX2 mutations have not been identified in humans. Here, we performed STX2 mutation analysis for 131 Japanese men clinically diagnosed with nonobstructive azoospermia. As a result, we identified a homozygous frameshift mutation [c.8_12delACCGG, p.(Asp3Alafs*8)] in one patient. The mutation-positive patient exhibited loss-of-heterozygosity for 58.4 Mb genomic regions involving STX2, suggesting possible parental consanguinity. The patient showed azoospermia, relatively small testes, and a mildly elevated follicle stimulating hormone level, but no additional clinical features. Testicular histology of the patient showed universal maturation arrest and multinucleated spermatocytes, which have also been observed in mice lacking Stx2. PCR-based cDNA screening revealed wildtype STX2 expression in various tissues including the testis. Our results indicate that STX2 nullizygosity results in nonsyndromic maturation arrest with multinucleated spermatocytes, and accounts for a small fraction of cases with nonobstructive azoospermia.

STAT5 Orchestrates Local Epigenetic Changes for Chromatin Accessibility and Rearrangements by Direct Binding to the TCRγ Locus.

The transcription factor STAT5, which is activated by IL-7R, controls chromatin accessibility and rearrangements of the TCRγ locus. Although STAT-binding motifs are conserved in Jγ promoters and Eγ enhancers, little is known about their precise roles in rearrangements of the TCRγ locus in vivo. To address this question, we established two lines of Jγ1 promoter mutant mice: one harboring a deletion in the Jγ1 promoter, including three STAT motifs (Jγ1P(Δ/Δ)), and the other carrying point mutations in the three STAT motifs in that promoter (Jγ1P(mS/mS)). Both Jγ1P(Δ/Δ) and Jγ1P(mS/mS) mice showed impaired recruitment of STAT5 and chromatin remodeling factor BRG1 at the Jγ1 gene segment. This resulted in severe and specific reduction in germline transcription, histone H3 acetylation, and histone H4 lysine 4 methylation of the Jγ1 gene segment in adult thymus. Rearrangement and DNA cleavage of the segment were severely diminished, and Jγ1 promoter mutant mice showed profoundly decreased numbers of γδ T cells of γ1 cluster origin. Finally, compared with controls, both mutant mice showed a severe reduction in rearrangements of the Jγ1 gene segment, perturbed development of γδ T cells of γ1 cluster origin in fetal thymus, and fewer Vγ3(+) dendritic epidermal T cells. Furthermore, interaction with the Jγ1 promoter and Eγ1, a TCRγ enhancer, was dependent on STAT motifs in the Jγ1 promoter. Overall, this study strongly suggests that direct binding of STAT5 to STAT motifs in the Jγ promoter is essential for local chromatin accessibility and Jγ/Eγ chromatin interaction, triggering rearrangements of the TCRγ locus.

A heterozygous mutation of GALNTL5 affects male infertility with impairment of sperm motility.

For normal fertilization in mammals, it is important that functionally mature sperm are motile and have a fully formed acrosome. The glycosyltransferase-like gene, human polypeptide N-acetylgalactosaminyltransferase-like protein 5 (GALNTL5), belongs to the polypeptide N-acetylgalactosamine-transferase (pp-GalNAc-T) gene family because of its conserved glycosyltransferase domains, but it uniquely truncates the C-terminal domain and is expressed exclusively in human testis. However, glycosyltransferase activity of the human GALNTL5 protein has not been identified by in vitro assay thus far. Using mouse Galntl5 ortholog, we have examined whether GALNTL5 is a functional molecule in spermatogenesis. It was observed that mouse GALNTL5 localizes in the cytoplasm of round spermatids in the region around the acrosome of elongating spermatids, and finally in the neck region of spermatozoa. We attempted to establish Galntl5-deficient mutant mice to investigate the role of Galntl5 in spermiogenesis and found that the heterozygous mutation affected male fertility due to immotile sperm, which is diagnosed as asthenozoospermia, an infertility syndrome in humans. Furthermore, the heterozygous mutation of Galntl5 attenuated glycolytic enzymes required for motility, disrupted protein loading into acrosomes, and caused aberrant localization of the ubiquitin-proteasome system. By comparing the protein compositions of sperm from infertile males, we found a deletion mutation of the exon of human GALNTL5 gene in a patient with asthenozoospermia. This strongly suggests that the genetic mutation of human GALNTL5 results in male infertility with the reduction of sperm motility and that GALNTL5 is a functional molecule essential for mammalian sperm formation.

Copy-number variations in Y-chromosomal azoospermia factor regions identified by multiplex ligation-dependent probe amplification.

Although copy-number variations (CNVs) in Y-chromosomal azoospermia factor (AZF) regions have been associated with the risk of spermatogenic failure (SF), the precise frequency, genomic basis and clinical consequences of these CNVs remain unclear. Here we performed multiplex ligation-dependent probe amplification (MLPA) analysis of 56 Japanese SF patients and 65 control individuals. We compared the results of MLPA with those of conventional sequence-tagged site PCR analyses. Eleven simple and complex CNVs, including three hitherto unreported variations, were identified by MLPA. Seven of the 11 CNVs were undetectable by conventional analyses. CNVs were widely distributed in AZF regions and shared by ~60% of the patients and ~40% of the controls. Most breakpoints resided within locus-specific repeats. The majority of CNVs, including the most common gr/gr deletion, were identified in the patient and control groups at similar frequencies, whereas simple duplications were observed exclusively in the patient group. The results imply that AZF-linked CNVs are more frequent and heterogeneous than previously reported. Non-allelic homologous recombination likely underlies these CNVs. Our data confirm the functional neutrality of the gr/gr deletion in the Japanese population. We also found a possible association between AZF-linked simple duplications and SF, which needs to be evaluated in future studies.

Follicle-stimulating hormone enhances recovery from low-dose doxorubicin-induced spermatogenic disorders in mice.

PURPOSE: We aimed to investigate the effects of FSH for promoting spermatogenesis in mice with low-dose doxorubicin-induced spermatogenesis impairment. METHODS: Eight-wk-old male imprinting control region mice were divided into three groups. Groups D and F received 0.5 mg/kg of doxorubicin twice weekly for 5 weeks. Group C received saline instead of doxorubicin. After inducing spermatogenesis impairment, group D was treated daily with saline for 4 weeks. Group F was given 1 IU of recombinant human FSH daily for 4 weeks. Spermatogenesis recovery was evaluated based on the testis weight, sperm count, histological assessment, and mating. The percentage of sperm with unfragmented deoxyribonucleic acid (DNA) was analyzed by single-cell pulsed-field gel electrophoresis, and the serum FSH levels were measured. RESULTS: The elevation of serum FSH advanced slowly. The testis weight, sperm count, percentage of seminiferous tubules with spermatogenesis, percentage of sperm with unfragmented DNA and pregnancy rate were significantly increased by the administration of FSH. CONCLUSION: Our study findings indicated that the immediate administration of exogenous FSH can promote the recovery from impaired spermatogenesis induced by low-dose doxorubicin before endogenous FSH increases to the maximum level.

Microhomology-mediated microduplication in the y chromosomal azoospermia factor a region in a male with mild asthenozoospermia.

Y chromosomal azoospermia factor (AZF) regions AZFa, AZFb and AZFc represent hotspots for copy number variations (CNVs) in the human genome; yet the number of reports of AZFa-linked duplications remains limited. Nonallelic homologous recombination has been proposed as the underlying mechanism of CNVs in AZF regions. In this study, we identified a hitherto unreported microduplication in the AZFa region in a Japanese male individual. The 629,812-bp duplication contained 22 of 46 exons of USP9Y, encoding the putative fine tuner of spermatogenesis, together with all exons of 3 other genes/pseudogenes. The breakpoints of the duplication resided in the DNA/TcMar-Tigger repeat and nonrepeat sequences, respectively, and were associated with a 2-bp microhomology, but not with short nucleotide stretches. The breakpoint-flanking regions were not enriched with GC content, palindromes, or noncanonical DNA structures. Semen analysis of the individual revealed a normal sperm concentration and mildly reduced sperm motility. The paternal DNA sample of the individual was not available for genetic analysis. The results indicate that CNVs in AZF regions can be generated by microhomology-mediated break-induced replication in the absence of known rearrangement-inducing DNA features. AZFa-linked microduplications likely permit production of a normal amount of sperm, although the precise clinical consequences of these CNVs await further investigation.

Regulation of IgA production by naturally occurring TNF/iNOS-producing dendritic cells.

Immunoglobulin-A has an irreplaceable role in the mucosal defence against infectious microbes. In human and mouse, IgA-producing plasma cells comprise approximately 20% of total plasma cells of peripheral lymphoid tissues, whereas more than 80% of plasma cells produce IgA in mucosa-associated lymphoid tissues (MALT). One of the most biologically important and long-standing questions in immunology is why this 'biased' IgA synthesis takes place in the MALT but not other lymphoid organs. Here we show that IgA class-switch recombination (CSR) is impaired in inducible-nitric-oxide-synthase-deficient (iNOS-/-; gene also called Nos2) mice. iNOS regulates the T-cell-dependent IgA CSR through expression of transforming growth factor-beta receptor, and the T-cell-independent IgA CSR through production of a proliferation-inducing ligand (APRIL, also called Tnfsf13) and a B-cell-activating factor of the tumour necrosis factor (TNF) family (BAFF, also called Tnfsf13b). Notably, iNOS is preferentially expressed in MALT dendritic cells in response to the recognition of commensal bacteria by toll-like receptor. Furthermore, adoptive transfer of iNOS+ dendritic cells rescues IgA production in iNOS-/- mice. Further analysis revealed that the MALT dendritic cells are a TNF-alpha/iNOS-producing dendritic-cell subset, originally identified in mice infected with Listeria monocytogenes. The presence of a naturally occurring TNF-alpha/iNOS-producing dendritic-cell subset may explain the predominance of IgA production in the MALT, critical for gut homeostasis.

The stable o-phthalaldehyde-ferrocene/6-ferrocenyl-1-hexanethiol pre-column derivatization high-performance liquid chromatography of dimethylarginine by novel dual fluorescence and electrochemical detector.

Monomethylarginine, asymmetric dimethylarginine and symmetric dimethylarginine were separated on a Wakopak Combi ODS with an acetonitrile-100 mm potassium phosphate buffer (pH 7.0; 1:1, v/v). Dimethylarginines were derived from o-phthalaldehyde for the fluorescence detector and from 6-ferrocenyl-1-hexanethiol for the electrochemical detector. The detection limits of the dimethylarginines in spiked plasma were 0.3-0.5 pmol by electrochemical detection and 1-2 pmol by fluorescence detection. The detection limits were improved over 30 times by electrochemical detection and 10 times by fluorescence detection compared with previous reports. In previous derivatization liquid chromatography, the reaction solutions, o-phthalaldehyde, 2-mercaptethanol and dimethylarginines were unstable and required quick derivatization at 4°C. By our proposed pre-column methods, the dimethylarginines were derivatized at room temperature and the fluorescent products were stable for 6 h. The manipulation performance was greatly advanced compared with previous LC reports. This is the first report on stable and sensitive dimethylarginines by dual detection. The selectivity was also improved by dual detection. The proposed method was applied to preliminary monitoring of dimethylargines in plasma and urine.

Event-related potentials in patients with adult attention-deficit/hyperactivity disorder versus schizophrenia.

Event-related potentials (ERPs) such as Nd, N2b, and P300 in an attentional task and an auditory oddball task were compared among 54 adult AD/HD patients, 43 schizophrenic patients (SZ), and 40 healthy age-matched volunteers (HC). It is known that Nd, N2b, and P300 reflect selective attention, voluntary attention, and cognitive context updating respectively. The peak amplitude of P300 was significantly lower in the adult AD/HD and SZ groups than in the HC group. The peak latencies of late Nd, N2b, and P300 were significantly longer in the SZ group than in the HC and adult AD/HD groups. Thus, attenuated amplitude and prolonged latency of various ERP components in the SZ group suggest the possibility of impairment of basic mechanisms underlying cognitive processing. Unlike the SZ group, the adult AD/HD group exhibited reduced amplitude of P300 but not prolonged latency. These findings suggest the existence of a different type of cognitive dysfunction in the adult AD/HD group, which might be closely related to attentional function.

IL-17A produced by gammadelta T cells plays a critical role in innate immunity against listeria monocytogenes infection in the liver.

IL-17A is originally identified as a proinflammatory cytokine that induces neutrophils. Although IL-17A production by CD4(+) Th17 T cells is well documented, it is not clear whether IL-17A is produced and participates in the innate immune response against infections. In the present report, we demonstrate that IL-17A is expressed in the liver of mice infected with Listeria monocytogenes from an early stage of infection. IL-17A is important in protective immunity at an early stage of listerial infection in the liver because IL-17A-deficient mice showed aggravation of the protective response. The major IL-17A-producing cells at the early stage were TCR gammadelta T cells expressing TCR Vgamma4 or Vgamma6. Interestingly, TCR gammadelta T cells expressing both IFN-gamma and IL-17A were hardly detected, indicating that the IL-17A-producing TCR gammadelta T cells are distinct from IFN-gamma-producing gammadelta T cells, similar to the distinction between Th17 and Th1 in CD4(+) T cells. All the results suggest that IL-17A is a newly discovered effector molecule produced by TCR gammadelta T cells, which is important in innate immunity in the liver.

[Adenocarcinoma of the rete testis. A case report].

Adenocarcinoma of the rete testis is a rare malignant tumor with a poor prognosis. About 60 cases of this adenocarcinoma have been reported in the literature. The diagnosis is often difficult and made incidentally. Herein, we report a case of adenocarcinoma of the rete testis and review the literature. Our patient was an 80-year-old man who presented with painless scrotal swelling for 2 years. Physical examination revealed an enlarged, hard mass of the left scrotum. The serum markers alpha-fetoprotein (AFP), beta-human chorionic gonadotropin (beta-HCG), and carcinoembryonic antigen (CEA) were negative. Magnetic resonance imaging (MRI) showed a left hydrocele with central necrosis of the testis. After 4 months, the patient presented with appetite loss, general fatigue, and pain in the left scrotum. Positron emission tomography (PET) was performed in another hospital, and the patient was referred for a left testicular tumor, multiple lung metastases, and para-aorta lymph node metastasis. The patient underwent left high inguinal orchiectomy. Pathological examination revealed a hard whitish mass around the testis involving the epididymis and tunica vaginalis and spreading under the subcutaneous tissue. Histological examination revealed adenocarcinoma in the hilum of the testis, which extended to the subcutaneous tissue but not to the surface of the scrotum. The tunica albuginea was intact, and no invasion of carcinoma in the testis was seen. After the histological diagnosis of adenocarcinoma of the rete testis was confirmed, computed tomography (CT) was performed and showed multiple pulmonary nodules and para-aortica lymph node swelling of 3 cm diameter. Because the patient did not wish to receive chemotherapy or other aggressive treatment, he has been followed-up with palliative care since his diagnosis. Although local recurrence has occurred 4 months later, he is still alive for 8 months since his diagnosis.

Mutation of GALNTL5 gene identified in patients diagnosed with asthenozoospermia.

Asthenozoospermia is commonly observed in infertile men. However, very few causative gene mutations have been identified because an efficient detection method has not been established. We previously identified a patient with asthenozoospermia carrying a heterozygous point deletion in GALNTL5 by detecting an abnormal reduction in the abundance of GALNTL5 and other marker proteins. To identify other mutations in GALNTL5, we screened sperm samples from 208 infertile men mainly diagnosed with asthenozoospermia using the same method, and conducted next-generation sequencing. Consequently, another case of GALNTL5 mutation was detected only in sperm at a low frequency but not in the somatic blood cells of a patient diagnosed with asthenozoospermia. In this patient, sperm motility improved and the mutation disappeared at 2 years after the first observation. In this man, carrying a heterozygotic deficiency of GALNTL5, the swim-up method was useful to concentrate the spermatozoa without mutation. Intracytoplasmic sperm injection of the selected motile spermatozoa into oocytes of the patient's partner resulted in successful conception, and a female child was safely delivered. These results suggest the feasibility of our approach for the screening and treatment of asthenozoospermia associated with GALNTL5 mutation.

Comparison of Productivity and Fecal Microbiotas of Sows in Commercial Farms.

Sow productivity, that is, the number of weaned piglets per sow per year, depends on their health status. The gut microbiota is considered a crucial factor in the health of pigs and may affect sow productivity. In the present study, we aimed to investigate the relationship between productivity and the fecal microbiotas of sows in different farms. Feces of sows were collected from 18 farms (10 samples/farm). A total of 90 fecal samples of high-reproductive performance farms were labeled as group H, and 90 fecal samples from low-reproductive performance farms were labeled as group L. Fecal microbiotas were analyzed by 16S rRNA metagenomics, and the organic acids and putrefactive metabolites of the microbiotas were measured. ß-diversity was significantly different between groups H and L (P < 0.01), and the relative abundances of 43 bacterial genera, including short-chain fatty acid-producing and fiber-degrading bacteria such as Ruminococcus, Fibrobacter and Butyricicoccus, significantly differed between groups (P < 0.05). In addition, the concentrations of acetate, propionate and n-butyrate were significantly higher in group H than in group L (P < 0.05). In conclusion, sow productivity in farms was likely associated with the compositions of the fecal microbiotas.

Exacerbating role of gammadelta T cells in chronic colitis of T-cell receptor alpha mutant mice.

BACKGROUND & AIMS: T-cell receptor (TCR) gammadelta T cells are an important component of the mucosal immune system and regulate intestinal epithelial homeostasis. Interestingly, there is a significant increase in gammadelta T cells in the inflamed mucosa of patients with ulcerative colitis (UC). However, the role of gammadelta T cells in chronic colitis has not been fully identified. METHODS: TCRalpha-deficient mice, which spontaneously develop chronic colitis with many features of human UC including an increase in gammadelta T-cell population, represent an excellent model to investigate the role of gammadelta T cells in UC-like colitis. To identify the role of gammadelta T cells in this colitis, we herein have generated TCRgamma-deficient mice through deletion of all TCR Cgamma genes (Cgamma1, Cgamma2, Cgamma3, and Cgamma4) using the Cre/loxP site-specific recombination system and subsequently crossing these mice with TCRalpha-deficient mice. RESULTS: An increase in colonic gammadelta T cells was associated with the development of human UC as well as UC-like disease seen in TCRalpha-deficient mice. Interestingly, the newly established TCRalpha(-/-) x TCRgamma(-/-) double mutant mice developed significantly less severe colitis as compared with TCRalpha-deficient mice. The suppression of colitis in TCRalpha(-/-) x TCRgamma(-/-) double mutant mice was associated with a significant reduction of proinflammatory cytokine and chemokine productions and a decrease in neutrophil infiltration. CONCLUSIONS: gammadelta T cells are involved in the exacerbation of UC-like chronic disease. Therefore, gammadelta T cells may represent a promising therapeutic target for the treatment of human UC.

Accumulation of gamma/delta T cells in the lungs and their roles in neutrophil-mediated host defense against pneumococcal infection.

The present study was designed to elucidate the role of Vgamma4(+) gammadelta T cells, a major subset of pulmonary gammadelta T cells, in host defense against infection with Streptococcus pneumoniae. The proportion and number of whole gammadelta T cells, identified as CD3(+) and TCR-delta(+) cells, and Vgamma4(+) gammadelta T cells, identified as CD3(+) and TCR-Vgamma4(+) cells, increased in the lungs at 3, 6 and 12h post-infection. Survival of infected mice and lung bacterial clearance were severely impaired in TCR-Vgamma4(-/-) mice compared with control wild-type (WT) mice. The impaired host protection in TCR-Vgamma4(-/-) mice correlated well with attenuated recruitment of neutrophils in lungs. MIP-2 and TNF-alpha synthesis in the infected tissues was significantly reduced in TCR-Vgamma4(-/-) mice compared with WT mice. Similar results were noted in the synthesis of TNF-alpha, but not clearly of MIP-2, by lung leukocytes stimulated with live bacteria. Our results demonstrate that Vgamma4(+) gammadelta T cells play an important role in the neutrophil-mediated host defense against S. pneumoniae infection by promoting the synthesis of TNF-alpha and possibly of MIP-2 in the lungs.

Cryopreservation of human sperm in patients with malignancy: First 2 years' experience.

Background: Patients with malignancy (n = 130) participated in the sperm cryopreservation program. Methods: After washing and concentrating, sperm was cryopreserved using KS-VIm cryoprotectant medium. Participant background factors such as age, marital status, underlying disease, presence or absence of previous treatment and semen findings (concentration, motility and morphology) were analyzed to determine parameters associated with the program. Results: Patients in their 20s were most common (64 cases) and 94 cases were unmarried at the first visit. The main underlying diseases were testicular tumor (53 cases), leukemia (43 cases) and malignant lymphoma (13 cases). The program was completed for 118 cases. For leukemia, all semen parameters were closer to normal in patients without previous treatment (untreated group, UG) compared with the treated group (TG). When semen findings in the UG were classified according to underlying disease, sperm concentration was lower in patients with testicular tumor compared with those who had leukemia or malignant lymphoma. Four couples underwent reproductive therapies with the cryopreserved sperm through assisted reproductive technology, and three babies were born to two couples. Conclusion: Sperm cryopreservation liberates patients with malignancy from iatrogenic infertility as a consequence of intensive therapy, allowing them to retain reproductive ability.

Obstructive azoospermia caused by low ligation of varicocele: A case report.

Varicocele is commonly observed in male partners of infertile couples. The surgical ligation of varicoceles under microscopy can be safely performed by a skilled andrologist with most patients subsequently experiencing an improvement in semen quality. This is the first case in which obstructive azoospermia occurred after high inguinal varicocelectomy. The vas deferens was disrupted near the internal inguinal ring by fibrous tissue. A vasovasostomy was performed and semen parameters subsequently recovered.

Identification and characterization of novel gut-associated lymphoid tissues in rat small intestine.

BACKGROUND: The crypt lamina propria of the mouse small intestine has been shown to harbor multiple tiny clusters filled with c-kit- and interleukin 7 receptor (IL-7R)-positive lympho-hemopoietic cells (cryptopatches; CPs). However, it has remained an open question whether similar lymphoid tissue are present in the gastrointesitinal tract in other animals. In the present study, we investigated whether the small intestine of rats harbored lymphoid tissues similar to mouse CPs. METHODS: Immunohistochemical and flow cytometric analyses were carried out using various antibodies, including those to c-kit and IL-7R molecules. RESULTS: Lymphocyte-filled villi (LFVs), populated predominantly with c-kit- and IL-7 receptor (IL-7R)-positive cells and less with T cell receptor (TCR)-alphabeta T cells were found throughout the small intestine of young adult rats. Although LFVs were absent from fetal rat intestine, they were first detected at around 2 weeks after birth. Notably, in most LFVs that settled in the antimesenteric wall of the small intestine in young adult rats, immunoglobulin M-positive B cells were also detectable at the bottom of the LFVs. In aged rats, lymphocytes in some LFVs displayed a different phenotype, comprising a large B-cell area that included a germinal center. Thus, these clusters represent the first description of isolated lymphoid follicles (ILFs) in the rat small intestine. CONCLUSIONS: The present study provides the first evidence for c-kit- and IL-7R-positive lymphocyte clusters in the rat small intestine. Our data also indicating that LFVs and ILFs may constitute novel organized gut-associated lymphoid tissues in lamina propria of the rat small intestine.

Onset of hepatic erythropoiesis after malarial infection in mice.

Plasmodium yoelii-infected erythrocytes were injected into mice with or without 6.5 Gy irradiation. This irradiation suppressed erythropoiesis and induced severe immunosuppression. However, these mice showed a rather delayed infection, suggesting that fresh erythrocytes may become malarial targets. In other words, malarial infection did not persist without newly generated erythrocytes in mice. We then examined erythropoiesis in the liver and bone marrow of mice with malaria. Surprisingly, erythropoiesis began in the liver. At this time, the serum level of erythropoietin (EPO) was prominently elevated and the EPO mRNA also became detectable in the kidney. Many clusters of red blood cells appeared de novo in the parenchymal space of the liver. These results revealed that malarial infection had a potential to induce the onset of hepatic erythropoiesis in mice.

Cadmium-induced testicular damage in a rat model of subchronic intoxication.

Background: Cadmium (Cd)-induced testicular damage in relation to spermatogenesis has not been well studied. We studied the mechanism of Cd-induced testicular damage in a rat model of subchronic intoxication. Methods: Male Sprague-Dawley rats were subcutaneously injected with 0.6 mg Cd/kg per day for 6 weeks. The concentration of Cd in urine, serum and testes was measured by using atomic absorption spectrophotometry. Testicular damage was evaluated by counting the spermatogonia (SG) and spermatocytes (SC) on one cut-surface of five seminiferous tubules in stages VII or VIII of spermatogenesis every week. The location of intratesticular cadmium was determined by using oxine-fluorescent cytochemistry. Results: There were no differences in the testes/bodyweight ratio between the study and control groups. The concentration of Cd in the testes increased more than 100-fold that in serum after week 2, suggesting active testicular Cd accumulation (1-3 mg/g tissue). Cadmium accumulation was detected in SG and SC. The number of SG and SC diminished significantly in the study group (week 2: SG 74%, SC 90%; week 4: SG 47%, SC 75%; week 6: SG 30%, SC 54% of the control, respectively). Conclusions: Cadmium accumulated in SG and SC, consequently reduced the number of these cells, and disturbed the spermatogenesis in this rat model of subchronic Cd intoxication. Therefore, the number of SG decreased in this rat model of subchronic Cd intoxication. (Reprod Med Biol 2002; 1: 59-63).