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PubMed2003

Changes in the expression of claudins and transepithelial electrical resistance of mouse Sertoli cells by Leydig cell coculture.

In the testis, tight junctions (TJs) between adjacent Sertoli cells are important for the formation of blood-testis barrier (BTB). To verify the role of paracrine interactions between the Sertoli and Leydig cells in the structure and function of BTB in testis, the expression of claudin-1 and -11, and transepithelial electrical resistance (TER) of the mouse Sertoli cells were examined under the Leydig cell coculture. TER of Sertoli cell monolayer was significantly larger under the Leydig cell coculture in comparison with the control culture. Meanwhile, the expression of claudin-1 slightly decreased and claudin-11 significantly increased in the Sertoli cells in the Leydig cell coculture compared with control. Testosterone significantly increased claudin-11 expression in cultured Sertoli cells. Taken together, it suggested that Leydig cell coculture changed the structure and functions of inter-Sertoli TJs in vitro. Interactions between Leydig and Sertoli cells might be involved in the development of functional blood testis barrier in mouse testis.

Animals↗
PubMed1996

Immunohisto- and immunocytochemical studies on the dynamics of TSH and GTH cells in normally metamorphosing, metamorphosed, and metamorphosis-arrested Hynobius retardatus.

The development and dynamics of TSH and GTH cells were studied immunohisto- and immunocytochemically in the salamander Hynobius retardatus, which had been reported to show neoteny in a specific environment and a precocious development and maturation of testis in goitrogen-treated larvae. Pituitary glands from normally metamorphosing and metamorphosed animals, and metamorphosis-arrested larvae which had been treated with goitrogens, were examined using anti-human TSH beta and anti-bullfrog LH beta sera. The immunoreactive TSH cells in the goitrogen-treated larvae began to exceed those in the controls in number at 40 days after hatching (stage 64). At the end of this experiment (220 days after hatching), the goitrogen-treated larvae had four times more immunoreactive TSH cells than the controls. The immunoreactive TSH cells in the goitrogen-treated larvae came to occupy nearly the whole area of the section of the pars distalis. Contrary to this, no significant differences were observed in the number of immunoreactive GTH cells between the goitrogen-treated larvae and the controls during their ontogeny. The number of immunoreactive GTH cells was much less than that of immunoreactive TSH cells. Immunocytochemistry at the electron microscopical level revealed many "thyroidectomy cells" with extraordinarily inflated ER and secretory granules which showed strong immunoreactivity with anti-TSH beta antibody only in the pars distalis of the goitrogen-treated larvae. These results suggest the possibility that TSH induces precocious testicular development and maturation in the goitrogen-treated larvae in H. retardatus.

Animals↗
PubMed1980

Radiation therapy for seminoma of the testis: results in British Columbia.

Between 1942 and 1978 radiation therapy was given to 362 patients with seminoma of the testis, 40 (11%) of whom had a history of maldescent of either testis. The disease was classified retrospectively according to the extent of the primary tumor, the involvement of the regional lymph nodes and the presence of distant metastases (the TNM system), and the results of treatment were analysed according to the classifications. Among the 275 patients referred for treatment at least 5 years before this analysis the 5-year survival rates were 87% overall, 96% for those with a T1 or T2 (relatively localized) tumour but no evidence of nodal involvement or distant metastases and 62% for the 24 with palpable or distant metastases at the time of clinical presentation. Of the 28 patients in whom the disease recurred 15 were successfully treated. A second primary testicular tumour developed in the contralateral testis of eight patients. The incidence of other cancers was not increased over the expected rate in the general male population of the same age.

Adult↗
PubMed1990

Ultrastructural evidence of mature Leydig cells and Leydig cell regression in the neonatal human testis.

The neonatal period in male development is characterized by an acute rise in serum testosterone, which peaks at 2 to 3 months of age. The purpose of this study is to examine the neonatal human testicular interstitium at 4 months for evidence of Leydig cell maturation, as well as any morphological criteria relating to the fate of Leydig cells during this period, specifically, for signs of cell regression. Leydig cells are described with impressive development of the steroid secreting apparatus, which are consistent with the mature Leydig cells found during early fetal development and in the adult. The outstanding feature of these cells is the "organelle association" of extensive, anastamosing tubules of smooth endoplasmic reticulum (SER), pleomorphic mitochondria with a component of tubular cristae, and abundant microperoxisomes associated with the SER. Well-developed Golgi elements, regionalized RER, and diverse cell inclusions are also characteristics of these cells. Reinke crystals and paracrystalline inclusions are absent. Gap junctions are common in this system and are notable in the asymmetric nature of the adjacent cytoplasmic components. These findings provide a morphologic correlate to the reported neonatal phase of testosterone production in man. Intermediate forms of Leydig cells are described with "organelle associations" including decreased SER with increased lipid droplets, and decreased SER with prominent cytoplasmic filaments and/or dramatic mitochondrial changes supportive of mitochondrial involution. Cells consistent with immature Leydig cells are also present. The rather impressive diversity in cell morphology present during this time frame of 4 months, slightly past the peak in testosterone production, provides evidence of Leydig cell regression and a continuity of the mature neonatal Leydig cells with the immature Leydig cells of childhood (Prince, 1984). There is also some evidence of cell degeneration. Although the developmental history of Leydig cells has been described for years as biphasic, it is time to view Leydig cell development in man as a triphasic event, fetal, neonatal, and pubertal.

Endoplasmic Reticulum↗
PubMed2001

Androgen receptor (AR), estrogen receptor-alpha (ER-alpha) and estrogen receptor-beta (ER-beta) expression in the testis of the newt, Triturus marmoratus marmoratus during the annual cycle.

Expression of androgen receptor (AR), estrogen receptor alpha (ER-alpha) and estrogen receptor beta (ER-beta) in the testis of the marbled newt (Triturus marmoratus marmoratus) was investigated, with special attention to changes during the annual testicular cycle, using light microscopy immunohistochemistry and Western blot analysis. Primordial germ cells, primary and secondary spermatogonia and spermatocytes showed a positive reaction to the 3 receptor antibodies during the annual reproductive cycle. Follicular cells were positive to AR, ER-alpha and ER-beta during the spermiogenesis and quiescence periods in the glandular tissue. Interstitial cells showed reactivity to AR, ER-alpha and ER-beta in the spermiogenesis and the quiescence periods, and presented no labelling to these receptors in the proliferative period. These findings suggest that, as in mammals, there is an androgen-estrogen regulation of the function and development of the newt testis.

Animals↗
PubMed1980

Post-pubertal female psychosexual orientation in incomplete male pseudohermaphroditism type 2 (5 alpha-reductase deficiency).

An 18 year-old 46,XY female-reared patient with incomplete male pseudohermaphroditism type 2 (5 alpha-reductase deficiency) was studied. She had a male habitus, Wolffian ducts derivatives, normal testes and small phallus; there were no Mullerian duct derivatives nor gynaecomastia. Clinical and genetic data were typical of the diagnosis which was corroborated by endocrinological studies. Normal LH, FSH, testosterone (T) and oestradiol and decreased dihydrotestosterone (DHT) plasma levels before and after hCG administration were found; the T:DHT ratio was highly increased. The histopathological studies of a testis biopsy showed a normal adult male pattern, and the meiotic chromosomes were interpreted as normal. After assessment of her psychosexual orientation, successful surgical and medical therapy to maintain and improve her femaleness was effectuated. The post-pubertal gender role switch commonly observed in these female-reared patients is discussed.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
PubMed2003

Effects of insulin-like growth factor I on steroidogenic enzyme expression levels in mouse leydig cells.

The role of IGF-I in Leydig cell maturation was studied by evaluation of: 1) steady state levels for nine mRNA species expressed specifically in Leydig cells of 35- and 50-d-old IGF-I-null mice and wild-type controls; 2) protein levels for 17 alpha-hydroxylase/C17-20 lyase, cholesterol side-chain cleavage, and type I 5 alpha-reductase (5 alpha R-1) in Leydig cells by immunocytochemistry; and 3) serum testosterone (T) and testicular interstitial fluid IGF-I levels. Expression levels of all mRNA species associated with T biosynthesis were lower in the absence of IGF-I stimulation. In contrast, androgen-metabolizing enzyme mRNA species had either normal (3 alpha-hydroxysteroid dehydrogenase) or higher expression (5 alpha R-1) levels in IGF-I-null mice (P < 0.05) relative to wild-type controls. None of the mRNA species studied changed developmentally in the mutant, whereas there were increases or decreases between d 35 and 50 in normal controls. Parallel trends were observed for average Leydig cell 5 alpha R-1 immunostaining intensity. T levels in mutants were initially higher during d 14-21, equivalent to normal on d 28, and then failed to increase pubertally, remaining at 30% of control levels (P < 0.01) in 90-d-old adult animals. In normal wild-type mice, interstitial fluid and plasma IGF-I levels were highest (P < 0.05) on d 24, indicating that the action of this growth factor on the testis peaks during pubertal development. These results show that in the absence of IGF-I, there is a failure of adult Leydig cells to mature, and that the reduced capacity for T production is caused by disproportionate expression of T biosynthetic and metabolizing enzymes.

Aging↗
PubMed1996

Pem: a testosterone- and LH-regulated homeobox gene expressed in mouse Sertoli cells and epididymis.

Few transcription factors in somatic cells of the testis and epididymis that could potentially regulate androgen-dependent developmental events during male gametogenesis have been identified. In this study we examined the regulation and expression of an orphan homeobox gene, Pem, which encodes a homeodomain related to those in the Prd/Pax gene family. RNase protection, in situ hybridization, and Northern blot analyses of wild-type and germ-cell-deficient mutant mice (W(V)/ W(V)) localized Pem transcripts to Sertoli cells of the testis. During prepubertal testicular development, Pem expression was dramatically induced on Day 9, approximately when germ cells are known to enter meiotic prophase. In adult mice, Pem transcripts were preferentially expressed in stages VII-VIII seminiferous epithelium, the androgen-dependent stages during which germ cells undergo the first step of meiosis. Pem gene expression depended on androgens and gonadotrophins, as demonstrated by a lack of expression in hypophysectomized mice, gonadotrophin-deficient hypogonadal (hpg) mutant mice, and androgen receptor-deficient (tfm) mutant mice. Injection of either testosterone or luteinizing hormone (LH) into hypophysectomized and hpg/hpg mice restored Pem expression in the testes to normal levels. The Pem gene was also shown to be specifically expressed in the proximal cauda and distal corpus regions of the epididymis, the regions where spermatozoa gain forward motility and fertilization competence. Pem expression in the epididymis did not depend on spermatozoa in the lumen of the testis, as shown in quaking (qk/qk) mutant mice, however, unlike in the testes, epididymal Pem expression required germ-cell-induced factors. Our results show that discrete cell types in male reproductive tissues transcribe and independently regulate the Pem homeobox gene. To our knowledge no transcription factors have previously been shown to depend on testosterone or LH for expression in Sertoli cells in vivo. Collectively, the data implicate Pem as a candidate to regulate a subset of androgen-dependent genes in the male reproductive system.

Animals↗
PubMed2003

Combined analysis of tumor growth pattern and expression of endogenous lectins as a prognostic tool in primary testicular cancer and its lung metastases.

The aim of this study was to glyco- and immunohistochemically analyze expression of distinct growth/adhesion-related markers of primary testicular carcinomas and their lung metastases in relation to the risk of developing lung metastases and survival of patients, and to correlate immunohistochemical staining profile and syntactic structure analysis in order to delineate new prognostic parameters for this tumor type. Clinical features of 50 patients with primary testicular carcinomas and their corresponding lung metastases were evaluated and compared to those of a control cohort of 25 cases. The set of eight probes including labeled galectins-1 and -3, specific non-cross-reactive antibodies against galectins-1, -3, and -8 as well as anti-Ki-67, anti-bcl-2, and anti-p53 was applied to formalin-fixed, paraffin-embedded tumor sections of both primary and metastatic lesions. Syntactic structure analysis computed staining intensities and structural features of the tumor cells. These parameters were set into relation separately and in combination to clinical data including tumor stages, smoking habits, applied cytostatic therapy, disease-free interval, and survival. The risk of testis cancer patients to develop lung metastases depends in descending order on the tumor cell type (non-seminoma versus seminoma), tumor cell heterogeneity (mixed versus monomorphous cell type), age of patients, and pT stage. The extent of differential expression of galectin-related features between primary and secondary lesions was pronounced. Prognostic correlations for distinct galectin-related features were delineated in combination with data from syntactic structure analysis, for example cluster radius of galectin-3-positive tumor cells and post-surgical and total survival. Lengths of disease-free interval and total survival of patients were also correlated to characteristics obtained by syntactic structure analysis and their combination with galectin data in the first place, then to smoking habits, percentage of proliferating cells in the primary and secondary tumors, and finally to expression of certain galectins and of p53. Patients with non-seminoma testicular cancer should be thoroughly controlled for lung metastases. Regarding marker selection, our study underscores that further investigation of the growth-regulatory network of galectins is clearly warranted.

Adult↗
PubMed1991

Human chorionic gonadotropin induces all stages of spermatogenesis in vitro in the male Japanese eel (Anguilla japonica).

In the cultivated male Japanese eel, spermatogonia are the only germ cells present in the testis. Using a newly developed organ culture system, we obtained evidence that human chorionic gonadotropin (HCG) can induce the entire process of spermatogenesis, in vitro, from spermatogonia to spermatozoa within 24 days. The HCG-induced spermatogenesis in vitro was accompanied by a marked activation of Sertoli cells and Leydig cells, occurring prior to the beginning of spermatogonial proliferation. These results indicate that gonadotropin triggers spermatogenesis in the Japanese eel and further suggest that this effect of gonadotropin is mediated through the actions of testicular somatic cells.

Anguilla↗
PubMed1999

Radiation-induced apoptosis and gene expression in neonatal kidney and testis with and without protein synthesis inhibition.

PURPOSE: To analyse the incidence of radiation-induced apoptosis, expression of two apoptosis-related genes, Bcl-2 and p53, and post-radiation levels of cell proliferation in the neonatal rat (4-5 days old) kidney and testis. MATERIALS AND METHODS: Apoptosis was quantified in control or treated kidney or testis at 2, 4, 6, 8 and 24h after 5 Gy of whole body X-irradiation (n=4 per group). Morphology (light and electron microscopy) and DNA gel electrophoresis were used to assess apoptosis. Temporal and spatial expression of Bcl-2 or p53 were analysed using immunohistochemistry. Administration of cycloheximide (1.5mg/kg) was used to determine whether new protein synthesis had a role in induction of apoptosis. Tritiated thymidine uptake and autoradiography were used to indicate alterations in cell proliferation (radiolabel administered 1 h prior to tissue collection) or S-phase cells undergoing radiation-induced apoptosis (radiolabel administered 1 h prior to irradiation). RESULTS: Apoptosis peaked at 4 h in the testis and 6 h in the kidney and was significantly higher in the renal nephrogenic zone than in the testis (p<0.05). Mitosis was almost completely negated after irradiation in both tissues. A higher proportion (almost fivefold) of the apoptotic cells died in S phase in the kidney than in the testis. Cycloheximide negated induction of apoptosis in the kidney, and markedly decreased apoptosis in the testis. Bcl-2 expression was highest in the differentiated zone of control kidneys and increased after irradiation in the nephrogenic zone, particularly near foci of apoptosis in developing nephrons. In the control testis, Sertoli cells had moderate expression of Bcl-2. After irradiation, there was complete absence of Bcl-2 expression in apoptotic Sertoli cells, with surviving cells increasing Bcl-2 expression. Irradiated kidney had more intense nuclear p53 expression compared with controls. In the testis, p53 that was present in controls continued to be expressed in surviving cells but not apoptotic cells in radiation-treated animals. CONCLUSIONS: Unique differences can be identified between the incidence and biomolecular control of radiation-induced apoptosis in the normal neonatal kidney and testis. These results may find application for minimizing damage to these normal neonatal tissues in the development of, for example, cancer treatment regimens.

Animals↗
PubMed2003

Hormonal changes in relation to lunar periodicity in the testis of the forktail rabbitfish, Siganus argenteus.

Correlation of hormonal changes in the testis and the lunar periodicity was studied using the forktail rabbitfish, Siganus argenteus, which spawns synchronously around the last quarter moon. Weekly change in sperm motility peaked around the last quarter moon. The pH and osmolality in the seminal fluid increased and decreased around the same lunar phase, respectively. These results suggest that the testis of this species develops toward the specific lunar phase. Human chorionic gonadotropin (hCG) stimulated in vitro production of 11-ketotestosterone (11-KT) in the testicular fragments around the full moon. When the testicular fragments and the sperm preparations were incubated, respectively, with testosterone (T) and 17alpha-hydroxyprogesterone (17alpha-OHP), conversion of T to 11-KT in the testicular fragments decreased and, alternatively, that of 17alpha-OHP to 17alpha,20beta-dihydroxy-4-pregnen-3-one (DHP) in the sperm preparations increased from the full moon to the last quarter moon. Administration of the fish with hCG or DHP prior to the predicted spawning lunar day resulted in increases in the sperm motility and the seminal fluid pH. Plasma level of DHP, but not T and 11-KT, increased after hCG injection. These results indicate that gonadotropin (GtH) and DHP are related to the final stage of testicular maturation, and that GtH acts through production of DHP in the testis. Moreover, the present study shows that use of the lunar cue(s) in the rabbitfish occurs in the higher part of the hypothalamus-pituitary-gonadal axis.

17-alpha-Hydroxyprogesterone↗
PubMed2005

High-performance liquid chromatographic analysis of bisphenol A and 4-nonylphenol in serum, liver and testis tissues after oral administration to rats and its application to toxicokinetic study.

A sensitive and simple method based on solid-phase extraction (SPE) and HPLC with fluorescence detection for the determination of bisphenol A (BPA) and 4-nonylphenol (4-NP) in rat serum, liver and testis tissues has been developed. The chromatographic conditions consisted of a C18 column and mobile phase composition of acetonitrile and water with flow rate of 1.0 ml/min. The fluorescence detection was performed at excitation and emission wavelengths of 227 nm and 313 nm, respectively. Under these conditions, BPA and 4-NP were well separated and showed good linearities in the ranges of 0.01-50.0 microg/ml for BPA and 0.15-150.0 microg/ml for 4-NP with correlation coefficients greater than 0.999. The detection limits of serum and tissue samples were 2.8 ng/ml and 1.4 ng/g for BPA and 5.6 ng/ml and 2.8 ng/g for 4-NP at a signal-to-noise ratio (S/N) of 3. The intra-assay and the inter-assay precisions were better than 11.4%. Recoveries of BPA and 4-NP were 78.6-95.0% and 80.2-93.4%, respectively. The proposed method was applied to a toxicokinetic study of BPA and 4-NP including individual and combined oral administration to rats. The results showed that 4-NP remarkably altered the toxicokinetic parameters of BPA in testis, while parameters of BPA were not obviously altered in serum and liver under the experimental conditions investigated. On the other hand, there was no significant difference in the toxicokinetics of 4-NP when administered with BPA.

Administration, Oral↗
PubMedDate not supplied

Characterization and developmental expression of a testis-specific adenosine deaminase mRNA in the mouse.

Adenosine is able to alter intracellular cAMP levels and to affect the physiological functions of sperm. It also modulates FSH action through its Gi protein coupled receptors. Adenosine deaminase (ADA), an enzyme regulating adenosine levels, exists in the plasma membrane of the sperm, but little is known about its action on testicular function. The present study investigates the expression of a testis-specific ADA mRNA with development and in comparison to several other tissues in the mouse. In addition, the sequence of a testis-specific ADA cDNA was determined from an adult mouse testis library. We demonstrate for the first time the presence of a major 1,350 bp testis-specific ADA mRNA and a weaker 1,200 bp ADA transcript whose developmental expression starts on day 28 of life. Sequence analysis of the testis-specific ADA cDNA indicated that exons 1 and 2, as well as the first 8 nucleotides of exon 3 of the somatic cell ADA cDNA were absent in the testicular ADA cDNA. The deduced open reading frame of the testis-specific ADA cDNA indicates absence of the first 51 amino acids at the 5' end that are present in the somatic cell ADA protein. The developmental onset of expression of the testis-specific ADA mRNA may be related to specific proliferation/differentiation events of spermatogenesis.

Adenosine Deaminase↗
PubMed1982

Ontogeny of cyclic nucleotides in embryonic chick gonads.

The cyclic nucleotides AMP and GMP show characteristic patterns of concentration throughout development in the gonads of the embryonic chick. In the ovary, cyclic AMP concentration varies depending upon whether the ovary is regressing (right) or developing (left). In the regressing right ovary cyclic AMP concentration is 4.25 pmol/10(6) cells on day 8 and 1.3 pmol/10(6) cells on day 15 of embryonic development. In the developing left ovary cyclic AMP is approximately one-half that of the right ovary and also decreases throughout this period (2.9 pmol/10(6) cells on day 8 and 0.75 pmol/10(6) cells on day 12 through hatching). Cyclic GMP levels, on the other hand, are similar in right and left ovaries on day 10 (4 and 5 fmol/10(6) cells, respectively). On day 12, however, cyclic GMP in the regressing right ovary increases 5.5-fold while that in the developing left ovary remains constant. In the testis, cyclic AMP and cyclic GMP remain at 0.9 pmol and 6 fmol per 10(6) cells, respectively, throughout embryonic development. Micromolar concentrations of cyclic AMP and cyclic GMP reciprocally inhibit the hydrolysis of each other to a similar degree in the developing left ovary and testis. In the regressing right ovary, however, the hydrolysis of cyclic GMP is not affected by cyclic AMP.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1996

Murine interleukin-11 (IL-11) is expressed at high levels in the hippocampus and expression is developmentally regulated in the testis.

IL-11, derived from a bone marrow stromal cell line, has pleiotropic effects on both hematopoietic cells and nonhematopoietic cells. However, no previous studies have systematically addressed expression of IL-11 in primary tissues in vivo and the relationship of IL-11 tissue specific gene expression and function of IL-11 is not clear. In the present study, we examined constitutive IL-11 expression in various murine adult tissues in vivo. IL-11 mRNA is expressed in a wide range of normal tissues (including hematopoietic organs) at levels only detected by RT-PCR. IL-11 protein was detected in brain and testis by Western blot analysis. The in vivo cellular distribution of IL-11 expression was examined by in situ hybridization. In brain, IL-11 message is distributed in granular layer dentate gyrus and pyramidal cell layers of hippocampus. IL-11 is also expressed in anterior horn cells and lateral column neuronal cells of the spinal cord. In testis, IL-11 mRNA is expressed in round spermatids at stage VI-IX seminiferous tubules. IL-11 expression in testis is restricted to developing spermatogonia and is developmentally regulated, since no expression is seen in mice genetically deficient in germ cells and in mice prior to sexual maturation. These expression data correlate with functional data demonstrating that IL-11 stimulates proliferation in vitro of a hippocampus neuronal progenitor cell line and administration of IL-11 in vivo accelerates recovery of spermatogenesis after cytotoxic therapy. These studies suggest that IL-11 may be an important regulator in neural and testicular function.

Animals↗
PubMed1988

Primary genetic control of somatic sexual differentiation in a mammal.

The classical view of mammalian sexual differentiation is that a gene on the Y chromosome transforms the indifferent gonad into a testis. The Leydig cells then secrete androgen which stimulates the development of the male reproductive tract, and the Sertoli cells secrete Mullerian inhibitory substance which inhibits the development of the female reproductive tract. In the absence of a testis, the Mullerian duct develops into the Fallopian tubes, uterus and vagina. Thus the whole of sexual differentiation is thought to be hormonally mediated as a consequence of this initial genetic determination of gonadal sex. We have found evidence in a marsupial mammal for extensive sexual dimorphisms which precede any morphological differentiation of the gonads. Thus the classical view of mammalian sexual differentiation may have over-emphasized the role of testicular hormones, and overlooked earlier genetic effects.

Animals↗
PubMed2003

Expression of vascular endothelial growth factor receptors during male germ cell differentiation in the mouse.

Overexpression of vascular endothelial growth factor (VEGF) in the testis of transgenic mice induces infertility, suggesting a potential role for VEGF in the process of spermatogenesis. Spermatogenesis occurs within the confines of the seminiferous tubules, and the seminiferous epithelium lining these tubules consists of Sertoli cells and germ cells in various stages of maturation. We investigated the source of VEGF and VEGF-target cells within the seminiferous tubules of the normal mouse testis. Sections of testes fixed in Bouin solution and embedded in paraffin were subjected to immunofluorescent staining with specific antibodies against VEGF, and its receptors, VEGFR-1 (Flt-1) and VEGFR-2 (Flk-1). Total RNA was extracted from isolated populations of Sertoli cells, type A spermatogonia, pachytene spermatocytes, and spermatids. Primer pairs specific for VEGF and its receptors were designed and reverse-transcriptase polymerase chain reaction (RT-PCR) was performed. Immunofluorescent studies indicated that VEGF is strongly expressed in the cytoplasm of Sertoli cells. VEGFR-1 and VEGFR-2 were not expressed by the Sertoli cell. In contrast, a differential expression of VEGF receptors was observed in germ cells. Although VEGFR-2 was expressed in the cytoplasm of type A spermatogonia, VEGFR-1 was expressed in the acrosomal region of spermatids and spermatozoa. Pachytene spermatocytes did not exhibit any staining. Further, we examined the transcription of VEGF and its receptors by RT-PCR. VEGF was actively transcribed only in Sertoli cells. The transcription of VEGFR-2 was confined to type A spermatogonia. Interestingly, VEGFR-1 was transcribed both in pachytene spermatocytes and round spermatids. The mRNA expression of VEGFR-1 and VEGFR-2 in germ cells was inversely correlated during postnatal development of the mouse testis. Thus, VEGF may play a potential role in regulating the initial stages of the process of spermatogonial proliferation through VEGFR-2 and spermiogenesis through VEGFR-1.

Animals↗