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At least 19 recordsLinked to original sources
PubMed1993

Effects of adenosine analog PIA (n-phenylisopropyladenosine) on FSH-stimulated cyclic AMP (cAMP) production in the rat seminiferous epithelium.

In rat seminiferous epithelium, FSH-stimulated cAMP production is cyclically modulated by spermatogenic cells and is highest in stages XIV-V and lowest in stages VII-VIII of the epithelial cycle. Adenosine has been proposed to be an inhibitory paracrine molecule in Sertoli cells. In this paper the effect of adenosine analog n-phenylisopropyladenosine (PIA) on FSH-stimulated cAMP production was studied in staged rat seminiferous tubules. In low responsive stages VII-VIII of the cycle, 100 nM and 10 microM PIA inhibited FSH-stimulated cAMP production by 24% and 28%, respectively. To study whether PIA effect is mediated through Gi-protein, pertussis toxin (PT) pretreatment was used to block the Gi-protein. PT pretreatments of 3 or 18 h caused 42% or 16% elevation in FSH-stimulated cAMP production, respectively. PIA blocked the stimulation caused by PT pretreatment. At 38 days post irradiation, when spermatocytes and round spermatids were decreased in number, in stages VII-VIII of the cycle the inhibitory effect of PIA was abolished. In high responsive stages XIV-V of the cycle, 100 nM PIA stimulated cAMP production by 27%, while 10 microM PIA had no effect. At 38 days post irradiation FSH response was decreased by 19% when compared to non-irradiated level, and PIA stimulated FSH-stimulated cAMP production by 22%. The results suggest that there are stage-specific mechanisms for adenosine-dependent regulation of FSH-stimulated cAMP production in the rat seminiferous epithelium. Advanced spermatogenic cells seem to maintain the mechanisms that include PIA-mediated inhibition of FSH response. Other mechanisms than PT-sensitive Gi-protein seem to be involved in the inhibition.

Animals↗
PubMedDate not supplied

Adverse effects of chronic GnRH antagonist administration on seminiferous epithelium in adult rats.

Seminiferous epithelium in adult rats was studied by light and electron microscopy after 5 weeks of chronic administration of GnRH antagonist (Ac-D2 Nal 1, D4ClPhe 2, DTrp 3, DArg 6, DAla 10; GnRH code-103-289-10, National Institutes of Health, USA). In these rats, the epithelium showed significant accumulation of vacuoles in more than 80% of the tubules, along with germ cell degeneration and nuclear pyknosis. Disruption in the process of spermatogenesis was also very much evident. In most of the tubules studied (greater than 90%), germ cell development was arrested beyond the pachytene spermatocyte stages. The vacuoles in the seminiferous epithelium were different sizes and when magnified were seen to consist of a thickened outer margin of solid nonfibrous coat within the Sertoli cell cytoplasm. Associated changes in the interstitium showed increased intertubular space but no inflammatory type of response. In actual cell counts, the decrease in the average number of macrophages was 32% and in Leydig cells 23%, while the total number of all types of cells in the interstitium was 30% less than that of the controls. Following the treatment, weights of testis, epididymis, seminal vesicle, and ventral prostate were drastically reduced. Rats treated with testosterone supplementation (60 micrograms/rat day) to GnRH antagonist recovered testicular and epididymal weights to approximately 57% and seminal vesicle and ventral prostate weights by 82.9 and 84%, respectively. Normalcy returned to the tubular epithelium and the interstitial cell counts were restored to original levels.

Animals↗
PubMed2004

Extracellular matrix: recent advances on its role in junction dynamics in the seminiferous epithelium during spermatogenesis.

Spermatogenesis takes place in the seminiferous epithelium of the mammalian testis in which one type A1 spermatogonium (diploid, 2n) gives rise to 256 spermatids (haploid, 1n). To accomplish this, developing germ cells, such as preleptotene and leptotene spermatocytes, residing in the basal compartment of the seminiferous epithelium must traverse the blood-testis barrier (BTB) entering into the adluminal compartment for further development into round, elongating, and elongate spermatids. Recent studies have shown that the basement membrane in the testis (a modified form of extracellular matrix, ECM) is important to the event of germ cell movement across the BTB because proteins in the ECM were shown to regulate BTB dynamics via the interactions between collagens, proteases, and protease inhibitors, possibly under the regulation of cytokines. While these findings are intriguing, they are not entirely unexpected. For one, the basement membrane in the testis is intimately associated with the BTB, which represents the basolateral region of Sertoli cells. Also, Sertoli cell tight junctions (TJs) that constitute the BTB are present side-by-side with cell-cell actin-based adherens junctions (AJ, such as basal ectoplasmic specialization [ES]) and intermediate filament-based desmosome-like junctions. As such, the relative morphological layout between TJs, AJs, and desmosome-like junctions in the seminiferous epithelium is in sharp contrast to other epithelia where TJs are located at the apical portion of an epithelium or endothelium, furthest away from ECM, to be followed by AJs and desmosomes, which in turn constitute the junctional complex. For another, anchoring junctions between a cell epithelium and ECM found in multiple tissues, also known as focal contacts (or focal adhesion complex, FAC, an actin-based cell-matrix anchoring junction type), are the most efficient junction type that permits rapid junction restructuring to accommodate cell movement. It is therefore physiologically plausible, and perhaps essential, that the testis is using some components of the focal contacts to regulate rapid restructuring of AJs between Sertoli and germ cells when germ cells traverse the seminiferous epithelium. Indeed, recent findings have shown that the apical ES, a testis-specific AJ type in the seminiferous epithelium, is equipped with proteins of FAC to regulate its restructuring. In this review, we provide a timely update on this exciting yet rapidly developing field regarding how the homeostasis of basement membrane in the tunica propria regulates BTB dynamics and spermatogenesis in the testis, as well as a critical review on the molecular architecture and the regulation of ES in the seminiferous epithelium.

Animals↗
PubMed1996

An ultrastructural and lectin-histochemical study on the seminiferous epithelium of the common tree shrew (Tupaia glis).

The seminiferous epithelium of the common tree shrew (Tupaia glis) was investigated using transmission electron microscopy and lectin-histochemistry. It was compared with that of shrews examined in previous studies. Some peculiar structures were detected in the tree shrew spermatid at the electron microscopic level. The most characteristic feature was the disposition of mitochondria in early spermatids. In cap and early acrosome-phase spermatids, mitochondria accumulated in one area of the spermatid cytoplasm and then dispersed in the late acrosome phase. Subsequently they again clustered to form the middle piece of spermatozoa. While the lamellar structure was clearly seen in the caudal region of the spermatid nucleus, it gradually disappeared during the process of elongation. The dilated area in the postacrosomal space of early round spermatids was also characteristic. The dilation was not detected in elongated spermatids. These structures were not recognised in the seminiferous epithelium of shrews. With respect to lectin histochemistry, the binding patterns in the spermatid acrosome of the tree shrew were similar to those of the musk shrew. However, PNA and BPA, which reacted with the Sertoli cell cytoplasm of the musk shrew, showed no reaction in the tree shrew Sertoli cell. Thus, except for some lectin binding patterns in the spermatid acrosome, no close similarity was recognised in the morphology of the seminiferous epithelium between tree shrews and shrews.

Acrosome↗
PubMed1983

Spermatogonial multiplication in the Chinese hamster. III. Labelling indices of undifferentiated spermatogonia throughout the cycle of the seminiferous epithelium.

Radioautography of whole mounts of seminiferous tubules of the Chinese hamster was performed after injection of [3H]thymidine. The labelling index (LI) of undifferentiated spermatogonia was determined throughout the whole cycle of the seminiferous epithelium. The LI of these cells was found to be highest between stages XI and IV. The LI for Apr and Aal spermatogonia decreases around stage III but remains at a relatively high level for As spermatogonia until stage VII. From these data, which agree well with previously recorded cell counts and mitotic indices (Lok, Jansen & Rooij, 1982a; Lok, Weenk & Rooij, 1982b), and from the known cell cycle properties (Lok et al., 1982a), the growth fractions of the various types of undifferentiated spermatogonia during the epithelial cycle could be calculated. Furthermore, it could also be calculated from the labelling indices that the proliferative activity of the As and Apr spermatogonia is sufficient to yield the necessary number of Aal/A1 spermatogonia for each cycle of the seminiferous epithelium. An interesting phenomenon is described; many more labelled Apr spermatogonia were found compared with the number of labelled As spermatogonia than one would expect in a steady state kinetic system. It is proposed that some of the labelled Apr spermatogonia are false pairs and still lose their cytoplasmic bridges at mitosis, thus yielding new As and/or Apr spermatogonia.

Animals↗
PubMed1995

Integrin receptor alpha 6 beta 1 is localized at specific sites of cell-to-cell contact in rat seminiferous epithelium.

With the aim of investigating the presence and role of integrin receptors in cell-to-cell interactions during spermatogenesis, we have immunolocalized alpha 6A integrin chain in the rat seminiferous epithelium. In both prepubertal and adult seminiferous epithelium, the antigen was found to be restricted to definite sites of intercellular contact, following a stage-specific distribution almost invariably identical to that known for beta 1 chain. In the adult seminiferous epithelium, positivity for both antigens was found exclusively around the profiles of elongating and maturing spermatids and, in most but not all stages, at a characteristic suprabasal position. In the prepubertal rat, the antigen is localized along a very regular suprabasal line of intercellular contacts. In immunoprecipitation experiments on both seminiferous epithelium explants and Sertoli cell cultures from 3-wk-old rats, anti-alpha 6A antibody coprecipitates a polypeptide of 118 kDa, presumably corresponding to beta 1 chain. These data strongly suggest that the integrin heterodimer alpha 6A beta 1 is expressed at sites of intercellular contact in the rat seminiferous epithelium. The stage-specific and restricted pattern observed by immunofluorescence suggests that this integrin is involved in regulatory interactions between Sertoli cells and germ cells during spermatogenesis.

Animals↗
PubMed1987

Transport of iron and transferrin synthesis by the seminiferous epithelium of the rat in vivo.

The transport of radioactive iron across the seminiferous tubules was analyzed in vivo by light-microscope quantitative radioautography. At 5 min after a single intratesticular injection of 55Fe-transferrin, a strong labeling of the basal aspect of the seminiferous epithelium was observed. Between 30 min and 2 h, the labeling on the basal aspect of the seminiferous epithelium decreased. This decrease was accompanied by a substantial increase of the radioautographic reaction over the cellular elements in the adluminal compartment. These results were consistent with the demonstration of 59Fe associated with meiotic spermatocytes and differentiating spermatids isolated by velocity sedimentation from testes injected with 59Fe-transferrin. Furthermore, after a single intratesticular injection of 59Fe-labeled human transferrin, radiolabeled rat transferrin was immunoprecipitated from homogenates of isolated tubules with a specific antibody and appeared as a single radioactive band on fluorographs of urea/polyacrylamide gels. Similarly, 59Fe-labeled rat transferrin but not 125I-transferrin was immunoprecipitated from rete testis fluids of testes infused with either 59Fe- or 125I-labeled human transferrin. Finally, the synthesis of testicular transferrin in vivo was demonstrated in fluorographs of immunoprecipitated transferrin after an intratesticular injection of 35S-methionine in rats whose livers were excluded from the general circulation by ligation of both the hepatic artery and the portal vein. Thus, our results demonstrated a unidirectional system of iron transport from the basal compartment of the seminiferous epithelium to the germ cells in the adluminal compartment involving two distinct transferrins, i.e., a serum transferrin and a testicular transferrin synthesized by the seminiferous epithelium.

Animals↗
PubMed1988

Repopulation of the seminiferous epithelium of the rhesus monkey after X irradiation.

Repopulation of the seminiferous epithelium became evident from Day 75 postirradiation onward after doses of 0.5, 1.0, and 2.0 Gy of X rays. Cell counts in cross sections of seminiferous tubules revealed that during this repopulation the numbers of Apale (Ap) spermatogonia, Adark (Ad) spermatogonia, and B spermatogonia increased simultaneously. After 0.5 Gy the number of spermatogonia increased from approximately 10% of the control level at Day 44 to 90% at Day 200. After 1.0 and 2.0 Gy the numbers of spermatogonia increased from less than 5% at Day 44 to 70% at Days 200 and 370. The number of Ad and B spermatogonia, which are considered to be resting and differentiating spermatogonia, respectively, already had increased when the number of proliferating Ap spermatogonia was still very low. This early inactivation and differentiation of a large part of the population of Ap spermatogonia slows down repopulation of the seminiferous epithelium of the primates. By studying repopulating colonies in whole mounts of seminiferous tubules various types of colonies were found. In colonies consisting of only A spermatogonia, 40% of the A spermatogonia were found to be of the Ad type, which indicates that even before the colony had differentiated, 40% of the A spermatogonia were inactivated into Ad. Differentiating colonies were also found in which one or two generations of germ cells were missing. In some of those colonies it was found that the Ap spermatogonia did not form any B spermatogonia during one or two cycles of the seminiferous epithelium, while in other colonies all Ap spermatogonia present had differentiated into B spermatogonia. This indicates that the differentiation of Ap into B spermatogonia is a stochastic process. When after irradiation the density of the spermatogonia in the epithelium was very low, it could be seen that the populations of Ap and Ad spermatogonia are composed of clones of single, paired, and aligned spermatogonia, which are very similar to the clones of undifferentiated spermatogonia in non-primates.

Animals↗
PubMed1995

Expression of mitochondrial heat shock protein 60 in distinct cell types and defined stages of rat seminiferous epithelium.

Changes in the level of the gene transcript of heat shock protein (hsp)60, a mitochondrial chaperonin, during the cycle of rat seminiferous epithelium and its cellular localization were studied. The seminiferous epithelium showed a cell type-specific expression of hsp60. Immunostaining of adult rat testis revealed localization in Sertoli and Leydig cells. In germ cells, mitochondria of spermatogonia and early primary spermatocytes were immunoreactive for hsp60. Mitochondria of all other germ cell types were completely negative for hsp60. Stage-specific expression of hsp60 was determined from pooled segments of stage-specific microdissected tubules by a combination of Western blotting and polymerase chain reaction (PCR). High concentrations of hsp60 were found in stages I-V and IX-XIV, and low levels were detected in the other stages, i.e., VI-VIII. In stages with high hsp60 expression, spermatogonia divide mitotically, whereas in stages lacking mitosis, the hsp60 level was much weaker. In seminiferous epithelium, two different types of mitochondria are present. Therefore, immunoelectron microscopy was used to differentiate these two morphologically distinct types of mitochondria. The crista type of mitochondria (e.g., in Sertoli cells and spermatogonia) reacted with the antibody against hsp60, whereas hsp60 was negative in so-called "condensed"-type mitochondria found in midpachytene spermatocytes and more advanced germ cells. It could be shown for the first time that expression of the hsp60 gene is regulated during the cycle of the seminiferous epithelium. The results indicate that the gene product is primarily needed during the initial steps of spermatogenesis in which most of the cell divisions occur, while its expression during the differentiation of spermatids and sperm is obviously not necessary. The presence of hsp60 in stages with mitotic activity suggests a very active mitochondrial protein import and protein assembly machinery that generates further mitochondria for the dividing cells.

Animals↗
PubMed2006

The seminiferous epithelium cycle and daily spermatic production in the adult maned wolf (Chrysocyon brachyurus, Illiger, 1811).

The duration of the seminiferous epithelium cycle was estimated in adult maned wolves (Chrysocyon brachyurus, Illiger, 1811), by applying intratesticular injections with tritiated thymidine. The total duration of the seminiferous epithelium cycle in this species was calculated in 8.99 days. So, taking into account that approximately 4.5 cycles of the seminiferous epithelium are necessary for the whole spermatogenesis process to complete, the production of spermatozoa from one spermatogonia will take about 40.45 days. The duration of the spermiogenesis was calculated to be 12.3 days. The eight stages of the seminiferous epithelium cycle were described by the tubular morphology method, which is based either on the form and position of the spermatid nuclei and the occurrence of meiotic divisions. The values of the relative frequency for the pre-meiotic, meiotic and post-meiotic phases in this species were 3.5, 0.78 and 4.8 days, respectively. The maned wolf produces about 29 million spermatozoa a day for each testis gram, therefore being classified among the species provided with a high spermatogenetic efficiency.

Animals↗
PubMed1995

Changes in protein prenylation and prenyltransferase activity in the rat seminiferous epithelium during early stages of spermatogenesis.

Changes in protein prenyltransferase activity, levels of prenylated protein, and the type of isoprenoid modification was described in cells of rat seminifereous epithelium and correlated with differentiative events of spermatogenesis. The activity of protein farnesyltransferase (PFT) was at least 10-fold higher than that for protein geranylgeranyltransferase-I (PGGT-I) in seminiferous epithelium and spermatogenic cells of prepubertal rats of different ages. Both activities increased during the meiotic stages of differentiation and peaked at 23 days of age. The activity of farnesyltransferase in seminiferous epithelium was the same as that in mixed spermatogenic cell populations from animals aged 9 and 23 days, indicating that the activity of this enzyme in somatic cells and germ cells was similar at these ages. Farnesyltransferase activities were similar and low in both pachytene spermatocytes and round spermatids from adult rats; however, the activity in pachytene spermatocytes from 23-day old animals was 2-fold higher than in adults. The highest activity was associated with intermediate-sized spermatocytes appearing late during meiosis. PGGT-I activity was at least 10-fold lower than farnesyltransferase activity and was not significantly different among all cell populations. Differentiation-dependent in vivo protein prenylation was demonstrated by labeling of seminiferous epithelium with [3H]mevalonic acid at different prepubertal ages. Total protein prenylation and the ratio of geranylgeranylated to farnesylated protein, in contrast to prenyltransferase activity, decreased with increasing age. Although 20-30-kDa proteins were the most highly labeled at all ages, [3H]-proteins from different-aged prepubertal rats showed age-dependent changes in the level of prenylation of at least 14 proteins as determined by two-dimensional (2D) electrophoresis. Prenylated proteins of round spermatids were distinguished from those of the spermatocytes by the lack of many 20-30-kDa proteins and by low geranylgeranyl/farnesyl (GG/F) ratios. These results show that independent changes in prenyltransferase activity and protein prenylation accompany the differentiation events during the premeiotic and meiotic stages of spermatogenesis. This suggests that prenylation in the seminiferous epithelium may be more dependent on available protein substrate than on protein prenyltransferase activity.

Aging↗
PubMed2001

Lectin affinity of the seminiferous epithelium in healthy and cryptorchid post-pubertal boars.

The present study describes the sugar content of the seminiferous epithelium, using lectin histochemistry, in healthy boars and in boars with unilateral and bilateral abdominal cryptorchidism. In healthy boars the apical cytoplasm of Sertoli cells exhibited abundant glucosyl (Con A and WGA lectins), galactosyl (HPA, DBA, SBA and PNA lectins), and fucosyl (AAA lectin) residues. Spermatogonia and spermatocytes contained abundant glucosyl (Con A and WGA lectins) and fucosyl (AAA lectin) residues. In spermatids, galactosyl (SBA and PNA lectins) and glucosyl (Con A and WGA lectins) residues increased progressively throughout spermiogenesis, and fucosyl (AAA lectin) residues decreased. As compared with healthy boars, the scrotal testis of unilateral cryptorchid boars showed decreased amounts of fucosyl (AAA lectin) and galactosyl (HPA and DBA lectins) residues on the Sertoli cell apical cytoplasm; spermatocytes exhibited higher content of glucosyl (Con A lectin) residues and spermatids showed altered nature of glucosyl (Con A and WGA lectins) and galactosyl (SBA and PNA lectins) complexes. In abdominal testes of unilateral and bilateral cryptorchid boars, immature Sertoli cells and spermatogonia showed decreased fucosyl (AAA lectin), and increased glucosyl (Con A and WGA lectins) and galactosyl (SBA and PNA lectins) contents. These results suggest that the seminiferous epithelium of healthy boars has polarized activity with the apical compartment implicated in germ cell-Sertoli cell adhesion and interaction, in transport of ions, substrates and fluids, and in acrosomal differentiation. In scrotal testes, unilateral abdominal cryptorchidism could lead to defective germ cell-Sertoli cell adhesion, impaired acrosomal differentiation and increased ionic transport in the apical compartment of the seminiferous epithelium. Unilateral and bilateral cryptorchidism could induce increased ionic transport and membrane permeability in the seminiferous epithelium of abdominal testes.

Animals↗
PubMed1983

Morphological pattern of response after administration of procarbazine: alteration of specific cell associations during the cycle of the seminiferous epithelium of the rat.

Procarbazine, an anti-cancer agent, administered intraperitoneally to adult, male rats induced a characteristic morphological pattern of response in the seminiferous epithelium. Seminiferous tubules of rats receiving 100 mg/kg procarbazine and higher dosages displayed spermatids which were less mature than those normally found within seminiferous tubules which show a particular cell association. Early spermatids in steps 1-7 of spermiogenesis appeared arrested in their development and were present in cell associations which had advanced normally. The most probable cause of this apparent germ cell arrest was a retardation of acrosomal development since procarbazine is known to affect RNA and consequently protein synthesis. Other features which indicated defective RNA synthesis were the presence of abnormal spermatid nucleoli and abnormally configured chromatoid bodies. This study demonstrates, in contrast to what is indicated by present dogma, that apparent and temporary germ cell arrest may occur under certain deleterious conditions. It also illustrates that particular cell types within a cell association may be out of synchrony with the remainder of the cells in a cell association.

Animals↗
PubMed1998

The establishment of spermatogenesis in the seminiferous epithelium of the pubertal golden hamster (Mesocricetus auratus).

The present study deals with initial spermatogenesis in the pubertal golden hamster (Mesocricetus auratus), in the course of which both the complex process of germ cell proliferation and differentiation and the cyclic pattern of organization of spermatogenesis are established. Germ cells pass through the complete sequence of spermatogenic differentiation from the A-spermatogonium up to the mature spermatid between days 12 and 38. During this period, germ cell development is already based on the pattern of organization and synchronization characteristic of adult spermatogenesis: 1. Judged by the germ cell types present, each of the successively appearing germ cell associations conforms to one of the adult stages of the seminiferous epithelium (stage conformity of the developmental steps of the pubertal seminiferous epithelium). 2. The overall intratesticular variance of the developmental levels reached in different tubular segments each covers almost exactly one cycle length of spermatogenesis. 3. There is a regular, continuous succession of developmental steps along the longitudinal course of the tubules which, in every single tubule, comprises the interval of one spermatogenic cycle ("wave" of the pubertal seminiferous epithelium). 4. Taken together, the latter two results indicate that the tubules of one given testis are equal to one another with respect to their developmental level, i.e., they develop synchronously. Germ cell propagation follows the clonal mode of proliferation. In quantitative terms, stage-related S-phase indices largely parallel the values of adult spermatogenesis. Both the frequently found germ cell apoptosis and degenerating intrameiotic spermatocytes correspond to degenerative phenomena in the adult seminiferous epithelium with respect to degenerative mode and stage-related occurrence. Germ cell development is closely related to the maturation of both Sertoli cells and Leydig cells. At two developmental phases, localized disturbances of germ cell differentiation occur which are specific to the pubertal period and which correlate with a maturational delay of Sertoli cells and Leydig cells, respectively: 1. Completion of Sertoli cell barrier formation may temporarily follow the initial onset of meiosis in the neighboring germ cells. As a result, mitotically dividing germ cells fall under the influence of a (hitherto hypothetic) "meiotic milieu" and characteristically degenerate (arrested germ cell mitoses). This relationship emphasizes the functional significance of the separation of the two seminiferous compartments and, in addition, heightens the understanding of the necessity of normal termination of Sertoli cell proliferation before germ cells initially enter meiosis. 2. The Leydig cell enzyme 11 beta-HSD, which is known to promote testosterone output, is established several days after the leading spermatids initially reach step 6 of spermiogenesis (which is immediately prior to the particularly testosterone-dependent start of elongation). The resulting selective developmental arrest of round spermatids of steps 6-6/7 between days 26 and 30 leads to a localized, partial desynchronization of the seminiferous epithelium, which can be traced for several days after the above-mentioned maturational delay of Leydig cells has been overcome and which is accompanied by an extensive degenerative disposition of the spermatids involved. The present investigation documents an organizational and synchronizational level of initial spermatogenesis that is similar to the situation in the adult animal. The analysis of temporarily occurring perturbations in the process of establishing the pubertal seminiferous epithelium emphasizes and specifies the close structural and functional relationships between the maturational state of somatic cells and germ cell differentiation.

11-beta-Hydroxysteroid Dehydrogenases↗
PubMed1997

Histological study of the seminiferous epithelium in the Japanese rat snake, Elaphe climacophora: identification of spermatogonium.

To clarify the features of the seminiferous epithelium of the Japanese rat snake, Elaphe climacophora, the identification of spermatogonium and the examination of features of cell to cell junctions were performed in the present study. As for the identification, 5-bromo-2-deoxyuridine (BrdU) incorporation was examined immunohistochemically to mark spermatogonia. The seminiferous epithelium was observed throughout a year at the electron microscopic level. BrdU immunoreactivity was detected not only in the cells of the first layer of the seminiferous epithelium but also in the second and/or third layers. The cells immunoreactive in the first layer did not seem to attach to the basement membrane and were recognized throughout a year. To investigate cell to cell junctions, we performed actin filament detection by phalloidin staining. Distribution of actin filaments was different from that in mammalian species. At the ultrastructural level, Sertoli-Sertoli cell junctions were observed. Sertoli cells formed junctional complexes. Tight junctions were clearly found, but lacked the backing by actin filaments. These results indicate that the blood-testis barrier of the Japanese rat snake was structurally different from that of mammalian species. In conclusion, the seminiferous epithelium of the Japanese rat snake is intermediate in morphology between amphibians and mammals.

Actins↗
PubMed1994

Duration of the cycle of the seminiferous epithelium, estimated by the 5-bromodeoxyuridine technique, in laboratory and feral rats.

The stability of the duration of the cycle of the seminiferous epithelium was determined by investigating incorporation of 5-bromodeoxyuridine into S-phase germ cells of normal and hemicastrated standard laboratory rats (Sprague-Dawley) and feral Brown/Norway rats (Rattus norvegicus). Feral rats were trapped on farms in the surroundings of Münster. The duration of the cycle of the seminiferous epithelium, determined at intervals of 12 days (3 h versus 12 days 3 h after 5-bromodeoxyuridine injection), was remarkably constant and similar in intact laboratory rats (12.49 +/- 0.05 days, n = 13, mean +/- SEM) and feral rats (12.44 +/- 0.06 days, n = 8). In hemicastrated laboratory and feral rats the duration of the cycle was similar to that in intact animals, indicating that hemicastration did not influence the kinetics of the seminiferous epithelium cycle. However, the coefficients of variation of the estimated duration of the cycle of the seminiferous epithelium were at least three times lower in hemicastrated rats (one testis from the same animal serving as reference point) compared with that of intact rats (the reference point based on the average staining frequency at 3 h). Overall, no significant differences between laboratory and feral rats could be observed with regard to testis weight and serum concentrations of FSH and testosterone. The number of cells per testis, determined by flow cytometry, was similar in laboratory and feral rats, except for a slight but significant difference in the haploid:tetraploid cell ratio (6.3 +/- 0.2 versus 7.5 +/- 0.3, P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1980

The cycle of the seminiferous epithelium of the domesticated giant rat (Cricetomys gambianus Waterhouse).

Spermiogenesis and the stages of the seminiferous epithelium in the testis of the giant rat were studied in domesticated animals. 19 steps of spermiogenesis on the basis of the development of the acrosomic system and flagellum were observed, and the cycle of the seminiferous epithelium can be divided into 14 stages. Although the developing spermatids and spermatozoa of the giant rat differed structurally from those of the albino rat, the general trend of development and the cellular content of the seminiferous epithelium were similar in both species of animals.

Animals↗