BCG-induced orchitis: Structural changes during the degeneration of seminiferous tubules of rats and rabbits

Summary The effect of BCG-induced orchitis on the structure of the seminiferous tubules in rats and rabbits was investigated by light and electron microscopy. The formation of cavities between Sertoli cells and the displacement of the cells of the spermatogenic cycle are the earliest changes to be observed. Individual Sertoli cells degenerate and separate from spermatocytes and spermatids. The latter form multinuclear complexes by a broadening of the intercellular bridges. The nuclei of spermatids undergo ring-like chromatin condensation in the rat and swelling in the rabbit. After the loss of spermatocytes and spermatids from the germinal epithelium, the remaining Sertoli cells have a very irregular shape and contain many residual bodies, which are probably derived from previously phagocytosed spermatids. They often contain crystalline inclusions. The nuclei of Sertoli cells show small chromatin condensations. In the rabbit, the tubular wall increases considerably in diameter. In the vicinity of a granuloma in the interstitium caused by BCG inflammatory cells accumulate around the wall of the seminiferous tubules. Although the basal lamina seems to be an obstacle, penetration of macrophages into the tubular lumen could be observed. However, this occurred only after the degeneration of the germinal epithelium.     

Specific localization of the basigin protein in human testes from normal adults, normal juveniles, and patients with azoospermia

Basigin is a transmembrane protein belonging to the immunoglobulin superfamily. Specific localization of the protein in normal human testes, from those of a 2-year-old boy to those of a 50-year-old man, and in testes with Sertoli cell only syndrome and germ cell arrest, is reported. Basigin localization was determined using an immunohistochemical technique with an antibody against human basigin. In the normal adult testes, basigin was detected at the periphery of both spermatocytes older than zygotene and round spermatids. In the juvenile testes, it was expressed in accordance with the appearance of pachytene spermatocytes. In this study, pachytene spermatocytes were detected in an 11-year-old boy. Basigin was not expressed in immature testes with germ cells younger than pachytene spermatocytes, namely in testes from boys aged 2-9 years. In testes from adult patients with Sertoli cell only syndrome, basigin was expressed at the periphery of Sertoli cells, but localization was confined to the adluminal compartment of the seminiferous tubule. In testes with germ cell arrest, the protein was expressed on germ cells from pachytene spermatocytes to step 2 spermatids, where present. The results show that in the normal human testes basigin is expressed with the onset of spermatocyte differentiation. Because human basigin is expressed in adult testes with Sertoli cell only syndrome, the protein seems to be synthesized in Sertoli cells and expression continues after these cells dedifferentiate in the seminiferous epithelium.     

The effects of ethylene glycol monomethyl ether on testicular histology in F344 rats

Ethylene glycol monomethyl ether (EGME) has been found to produce testicular atrophy in experimental rodents. The studies that follow were designed to determine the testicular cell type(s) most susceptible to EGME administration. For histologic studies, F344 rats were gavaged with 150 mg/kg/day of EGME 5 days per week, and serially sacrificed. In sections from perfusion-fixed tissue, necrotic changes were observed in some meiotic and premeiotic spermatocytes 24 hours after a single dose. Also, nuclear condensation was seen in occasional early pachytene spermatocytes. These effects were magnified after two doses; there were more necrotic pachytene and meiotic spermatocytes than necrotic stage I pachytene spermatocytes. By day 4, testes from all treated animals were affected; there was a pronounced maturation-depletion effect, seen as the absence of round spermatids from tubules in stages I to III. These effects continued to develop at days 7 and 10, leaving only Sertoli cells, spermatogonia, and late stage spermatids populating the epithelium. Other animals were treated similarly, but subject to efferent duct ligation 16 hours prior to sacrifice. Fluid production, as judged by weight gain in the testes after efferent duct ligation, was unaffected by EGME treatment. Analysis of the fluid collected at the rete testis indicated that there was no treatment-related change in the relative amounts of androgen binding protein. The data indicate that the spermatocyte is the primary target cell for the histologic effects of EGME in the testis of F344 rats.     

Age-dependent Sertoli cell responsiveness to germ cells in vitro

This study investigated the effect of germ cells (greater than 80% mid- and late-pachytene spermatocytes) on the secretion of androgen binding protein (ABP) and transferrin by monolayer cultures of Sertoli cells isolated from rats aged 10, 18 or 26 days. There was an age-dependent increase in secretion of ABP and transferrin. Treatment of the Sertoli cell monolayers with hypotonic buffer to remove residual germ cells reduced this increase significantly. On the other hand, addition of germ cells to hypotonic-treated Sertoli cell monolayers increased both basal and FSH + testosterone-stimulated ABP and transferrin secretion at all three ages, although Sertoli cells from 10-day-old animals showed the greatest response. Moreover, addition of germ cells reduced responsiveness to FSH + testosterone in Sertoli cell monolayers obtained from rats aged 18 or 26 days. In monolayers obtained from 10-day-old rats, the opposite effect was noted in the case of ABP secretion. The stimulatory effect of germ cells on ABP and transferrin secretion was proportional to their number, and was reversed 48 h after the germ cells added previously were removed by hypotonic treatment. Whereas the reversal was complete with cultures of Sertoli cells isolated from 18- and 26-day-old rats, approximately 40% of the stimulatory effect remained after removal of germ cells from cultures from the 10-day-old age group. Adhesion of germ cells to Sertoli cell monolayers was also found to be age-dependent, with the largest proportion of added germ cells adhering to Sertoli cells isolated at 18 and 26 days of age. It is concluded that germ cells can significantly and differentially modulate the basal and hormone-stimulated secretory activity of Sertoli cells in vitro and that Sertoli cell responsiveness to germ cells (pachytene spermatocytes) is age-dependent and seems to appear early during the maturation process, before these germ cells appear in the testis.     

Regulatory influence of germ cells on sertoli cell function in the pre-pubertal rat after acute irradiation of the testis

While germ cell regulation of Sertoli cells has been extensively explored in adult rats in vivo, in contrast, very little is known about germ cell influence on Sertoli cell function at the time when spermatogenesis begins and develops. In the present study various Sertoli cell parameters (number, testicular androgen binding protein (ABP) and testin, serum inhibin-B and, indirectly, follicle-stimulating hormone (FSH)) were investigated after the exposure of 19-day-old rats to a low dose of 3 Grays of gamma-rays. Differentiated spermatogonia were the primary testicular targets of the gamma-rays, which resulted in progressive maturation depletion, sequentially and reversibly affecting all germ cell classes. Testicular weight declined to a nadir when pachytene spermatocytes and spermatids were depleted from the seminiferous epithelium and complete or near complete recovery of spermatogenesis and testicular weight was observed at the end of the experiment. Blood levels of FSH and ABP were normal during the first 11 days after irradiation, when spermatogonia and early spermatocytes were depleted. While the number of Sertoli cells was not significantly affected by the irradiation, from days 11-66 after gamma-irradiation, ABP production declined and FSH levels increased when pachytene spermatocytes and spermatids were depleted and the recovery of these parameters was only observed when spermatogenesis was fully restored. Comparison of the pattern of change in serum levels of inhibin-B and testicular levels of testin and of germ cell numbers strongly suggest a relationship between the disappearance of spermatocytes and spermatids from the seminiferous epithelium and the decrease in levels of inhibin-B and increase in levels of testin from 7 to 36 days post-irradiation. Levels of testin and inhibin-B were restored before spermatogenesis had totally returned to normal. In conclusion, this in vivo study shows that pre-pubertal Sertoli cell function is under the complex control of various germ cell classes. This control presents clear differences when compared with that previously observed in adult animals and depends on the Sertoli cell parameter of interest, as well as on the germ cell type.     

Selective uptake by the Sertoli cells of cytoplasm from normal spermatogonia in the rat testis

Electron microscopical examination of germ cells during their development from early type A spermatogonia to late pachytene spermatocytes showed that small, spherical pseudopodia emerged from type B spermatogonia and, to a lesser degree, from intermediate spermatogonia and early spermatocytes. Serial sections showed that the pseudopodia pinched off from the type B spermatogonia and were engulfed by the adjacent Sertoli cells. Groups of dense bodies were found in the Sertoli cells adjacent to the engulfed islands of germ cell cytoplasm. At a few instances islands of germ cell cytoplasm were seen to fuse with dense bodies in the Sertoli cells. The fate of the cytoplasmic islands is unknown, but phagocytosis by the Sertoli cells may be suggested. The findings indicate a new type of interaction between Sertoli cells and certain classes of spermatogonia.     

Influence of age, hormones and germ cells on glutathione S-transferase activity in cultured Sertoli cells

Glutathione S-transferase (GSH-S-T) activity was measured, using 1-Cl-2,4-dinitrobenzene as substrate, in Sertoli cell cultures obtained from rats aged 10, 18, and 26 days. The GSH-S-T activity showed a significant increase with age of the Sertoli cell donor. When cultures were treated with hypotonic solution, in order to eliminate residual contaminating germ cells, the age dependent increase in enzyme activity was less pronounced. FSH, but not testosterone, increased enzyme activity in all cultures. Addition of freshly isolated germ cells (mainly pachytene spermatocytes) to hypotonic-treated Sertoli cell monolayers enhanced GSH-S-T activity at all ages. It is concluded that GSH-S-T activity can be measured in cultured Sertoli cells during the period of onset of spermatogenesis (10-26 days). This enzyme activity is dependent on age of the Sertoli cell donor and is influenced by FSH and germ cells. Since GSH-S-Ts are actively engaged in cell detoxificative functions through conjugation of xenobiotics with glutathione, the present findings suggest that this enzyme may have a relevant protective role during the critical period when spermatogenesis is being established.     

Lamellar germ cell processes: structures for possible interaction between germs cells and Sertoli cells during spermatogonial differentiation and early meiotic prophase

The recent finding of a stage-dependent topographical relationship of basally located germ cells to Sertoli-Sertoli interspaces in the rat testis (Ulvik 1983a) has suggested a focal interaction between Sertoli cells and early germ cells at the sites where 2 Sertoli cells meet over a basal germ cell. Focal, stage-dependent interaction between Sertoli cells and germ cells may require specializations of the germ cell membrane. Therefore, in the present work the surface of spermatogonia and spermatocytes has been studied under the electron microscope throughout the cycle of the seminiferous epithelium. Lamellar processes, 1–3 μm long, were found to emerge from germ cells and protrude into the spaces between the overlying Sertoli cells. The processes appeared on differentiating type A spermatogonia after stage VI, on intermediate and type B spermatogonia, and on leptotene, zygotene, and early pachytene spermatocytes; however, they were not found on type A spermatogonia prior to stage VII or on preleptotene spermatocytes at stage VII. The lamellar processes are thus stage-specific and may be sites of focal interaction with the Sertoli cells. Since the cell processes always protrude into the Sertoli-Sertoli interspaces this finding supports the hypothesis of focal, stage-dependent interaction between early germ cells and Sertoli cells via the narrow Sertoli-Sertoli interspaces.     

Immunohistochemical localization of calmodulin in the testes of patients with idiopathic male infertility

The localization of calmodulin in testes of patients with idiopathic male infertility was studied using the indirect immunoperoxidase method. Specimens were obtained by testicular biopsy from 55 patients. They were divided into 26 cases of hypospermatogenesis, 11 cases of maturation arrest (8 of primary spermatocyte arrest and 3 of spermatid arrest) and 18 cases of Sertoli cell-only syndrome. Regardless of the type of testicular pathology, the types of immuno-reactive cell and the intensities of staining were the same as those in the normal testis. That is, staining for calmodulin was first found to be positive in early pachytene primary spermatocytes. It became intense in late pachytene primary spermatocytes and round spermatids. By contrast, elongated spermatids and spermatozoa were not stained. Sertoli cells were stained slightly or not at all. A calmodulin-staining index (CaM-S index) was defined as the proportion of primary spermatocytes that were stained intensely for calmodulin relative to the total number of primary spermatocytes. The indices for the testes of men with complete spermatocyte maturation arrest were significantly lower than those for the testes of normal controls and of men with hypospermatogenesis.
Degenerating late pachytene spermatocytes observed in the testes of men with spermatocyte arrest showed low calmodulin-specific immunoreactivity. Such a decrease in numbers of normal late pachytene spermatocytes might be responsible for the low CaM-S index in cases of complete spermatocyte arrest.     

Construction and preliminary characterization of a series of mouse and rat testis cDNA libraries.

We have constructed a series of 23 cDNA libraries from mouse and rat testicular cells. These include libraries made from whole, intact adult testes; seminiferous tubule cells from adult testes; combined populations of primary spermatocytes from 18-day-old mouse testes; and isolated populations of primitive type A spermatogonia, type A spermatogonia, type B spermatogonia, preleptotene spermatocytes, leptotene plus zygotene spermatocytes, juvenile pachytene spermatocytes, adult pachytene spermatocytes, round spermatids, Sertoli cells from 6-, 8-, 17-, and 18-20-day-old mice, and peritubular cells from 18-20 day old mice, all recovered from outbred white Swiss (CD-1) mice. We also constructed libraries from whole adult testes from five other lines of mice: C57 Bl6/J, C3 HEB, BDF-1, Balb/c, and 129 Sv. Finally, there are two libraries made from populations of Sertoli cells and peritubular cells isolated from testes of 20-day-old Sprague-Dawley rats. Enzymatic dissociation, followed by gradient separation or plating/lysing techniques, was used to prepare populations of specific cell types in purities of 85-98%. cDNAs were synthesized from poly A+ mRNA primed with oligo dT and unidirectionally cloned into the lambda Uni-Zap XR expression vector from Stratagene. Primary titers ranged from 2.1 x 10(5) to 2.9 x 10(8) plaque-forming units, and insert sizes averaged 1.0-1.2 kb. These libraries have been amplified once and submitted to the American Type Culture Collection (ATCC) for distribution to interested investigators. ATCC accession numbers are provided.     

Effect of germ cells on vectorial secretion of androgen binding protein and transferrin by immature rat Sertoli cells in vitro

The influence of germ cells (greater than 85% pachytene spermatocytes) on vectorial secretion of androgen binding protein (ABP) and transferrin by immature rat Sertoli cells was investigated using two-compartment culture chambers. The ratio of ABP secreted into the outer and inner compartment in control cultures of Sertoli cells alone was 1.9, and was not influenced by either FSH or testosterone. Co-culture of Sertoli cells in direct contact with germ cells in the presence of FSH decreased this ratio, the decrease being most pronounced (0.7) after 2 days of co-culture. This effect was not observed if the germ cells were not in direct contact with Sertoli cell monolayers. The outer to inner compartment ratio of transferrin in Sertoli cell-alone cultures was 1.6 and, in contrast to ABP, was not significantly influenced by the addition of germ cells, even in the presence of FSH. It is concluded that in immature rat Sertoli cells the polarity of ABP secretion, but not that of transferrin, may be regulated by pachytene spermatocytes (and possibly other germ cells), and that this process is FSH-dependent.     

Inhibition of RNA and DNA synthesis in Sertoli cells by co-culture with spermatogenic cells

Sertoli cell monolayers were prepared from 30-day-old rat testes and cultured for 7 days to eliminate contaminant germ cells. Some of these monolayers were co-cultured with a spermatogenic cell preparation enriched in pachytene spermatocytes and round spermatids (fraction 3 from a Percoll gradient), isolated from 30-day-old rat testes. After co-culture for 4 to 48 h, germ cells were removed. RNA synthetic activity in rat Sertoli cell cultures alone was 216,800 +/- 66,480 dpm [3H]uridine.2h-1 X 10(6) cells-1 (mean +/- SD) compared to 98,390 +/- 23,595 in rat Sertoli cells which had been co-cultured with germ cells of fraction 3 for 24 h (P less than 0.01). By contrast, RNA synthesis in Sertoli cell monolayers prepared from immature pigs were unaffected by co-culture with rat germ cells. A similar inhibitory effect of germ cells was observed in rat Sertoli cells stimulated with FSH or testosterone. Culture medium, conditioned by 20 h culture of a fresh preparation of rat spermatogenic cells of fraction 3, was active in inducing the inhibitory effect on RNA synthesis in rat Sertoli cells. Co-culture of rat Sertoli cells with germ cells of this fraction also decreased the incorporative of [3H]thymidine into DNA in rat Sertoli cells, from 9061 +/- 3339 to 4766 +/- 526 dpm.2h-1 X 10(6) cells-1 (P less than 0.01), but no such change was found in pig Sertoli cells. A different spermatogenic cell preparation, partially deprived of pachytene spermatocytes (fraction 5), stimulated rat Sertoli cell DNA synthesis (Sertoli alone 7833 +/- 2550, Sertoli cells which had been in co-culture with germ cells of fraction 5, 13,300 +/- 2279 dpm.2h-1 X 10(6) cells-1, P less than 0.05). These inhibitory actions of some germ cells on Sertoli cells were observed together with the previously reported simultaneous stimulatory effect of Sertoli cells on germ cells. These Sertoli cell-germ cell interactions of detected in culture may represent regulatory influences operating in vivo.     

Endocrine correlates of meiosis in the male rat.

Changes in the proportion of cells within various DNA classes of dispersed testicular cells from the developing rat were monitored by microflow fluorometry and correlated with changes in the function of the pituitary (FSH), of the Leydig cells (androgens) and Sertoli cells (androgen-binding proteins, ABP). Peaks of androgens and of FSH appeared simultaneously and coincided with an accumulation of tetraploid cells and with the first appearance of haploid cells in the testis and ABP in the epididymis. Estrogen treatment (5 micrograms/day) of developing rats from day 7 completely prevented the appearance of haploid cells in the testis as well as ABP in the epididymis. In these animals the wave of tetraploid cells started and progressed normally, indicating that transformation and progression of germinal cells to the stage of the primary spermatocytes were taking place. A combined treatment with FSH and dihydrotestosterone propionate (DHTP) resulted in a premature start of Sertoli cell secretion of ABP into the epididymis, but in a normal appearance of haploid and tetraploid cells. The time correlation between peaks in FSH/androgens, the start of Sertoli cell secretion, and the occurrence of haploid cells in the testis stresses the importance of these two hormones for normal Sertoli cell function and the importance of a functional Sertoli cell for the completion of meiosis.     

Secretion of androgen binding protein by Sertoli cells is influenced by contact with germ cells

Sertoli cells were cultured alone or with germ cells to evaluate the effect of the association with germ cells on the secretory activity of Sertoli cells. Secretion of androgen-binding protein, which is specifically secreted by Sertoli cells, was measured under several experimental conditions. The following experimental models were utilized: 1) cultures of explants of seminiferous epithelium from prepubertal animals in which germ cells adherent to Sertoli cells are present (Sertoli cell enriched cultures); 2) monolayers formed only by Sertoli cells, obtained by removing germ cells from Sertoli cell enriched cultures, and 3) cocultures of Sertoli cell only cultures and germ cell populations at defined stages of differentiation. The results obtained indicated that FSH-induced ABP secretion was greatly reduced in Sertoli cell only cultures as compared to enriched Sertoli cell cultures, and that this difference was stable throughout the first eight days of culture. In addition, cocultures of Sertoli cell only cultures with germ cells induced an increase of ABP when cocultured germ cells were at differentiation stages, such as pachytene spermatocytes, which are able to recognize and firmly adhere to the Sertoli cell monolayers. Cocultures with round spermatids, which do not adhere to Sertoli cells, did not increase the amount of FSH-induced ABP production. The addition of nongerminal cells such as lymphocytes and fibroblasts were also not effective in stimulating ABP secretion. Surface interaction between Sertoli cells and cocultured germ cells seemed to be necessary for this FSH-induced ABP production.(ABSTRACT TRUNCATED AT 250 WORDS)     

Developmental expression of c-kit protooncogene in the rat testis

IntroductionInmammalianembryos,thegermcelllinebeginswithprimordialgermcelIs,andinmales,primordialgermcellsbecomegono-cytes,thece1lprecursorsofthespermatogoni-a.ThedevelopmentofanormaltestisdependsupontheproliferationofprimordialgermcellsandtheiraggregationwithSertolicellprecur-sorsLl:.Theseeventshavebeenshowntobeassociatedwiththeexpressionofthec-kitProtooncogenemappedtothe"whitespottinglocus(W)~ofthemouse[2,3j.Thec-kitPro-tooncogeneencodesatransmembranetyrosinekinasereceptor(4,5).Thestructu…     

Neonatally administered diethylstilbestrol retards the development of the blood-testis barrier in the rat

Newborn rats were treated with 10 microg of diethylstilbestrol (DES) on alternate days from the 2nd to the 12th postnatal day, and the testes were sequentially examined up to 105 days of age by light, electron, and confocal laser microscopy. In control rats, spermatozoa and step 19 spermatids were observed in stage VIII seminiferous tubules at 56 days of age. Spermatogenic cells in DES-treated rats differentiated normally from birth until 21 days of age, after which differentiation continued only to the pachytene-spermatocyte stage. From this age onward, spermatogenic cells older than pachytene spermatocytes were not found until 56 days of age. After this point, the cells resumed differentiation and finally became spermatozoa by 91 days of age; that is, 35 days later than control rats. Electron and confocal laser microscopy showed that in the normal rat, the formation of the ectoplasmic specialization between adjoining Sertoli cells was observed as early as 20 days of age. In contrast, the specialization was not formed until 56 days of age in DES-treated rats. Furthermore, the delay in functional maturation of this structure as the blood-testis barrier was confirmed by intercellular tracer experiments. It is clear that neonatal administration of DES delayed the establishment of the blood-testis barrier for 4 weeks. Consequently, during this period, pachytene spermatocytes were exfoliated from the seminiferous epithelium without completion of meiosis.     

Follicle-stimulating hormone and testosterone stimulation of immature and mature Sertoli cells in vitro: inhibin and N-cadherin levels and round spermatid binding.

The in vitro response of Sertoli cells isolated from adult rat testes to testosterone (T) and follicle-stimulating hormone (FSH) treatment was investigated. Sertoli cells from >70-day-old Sprague-Dawley rats were isolated by a combined enzymatic treatment followed by the removal of the majority of contaminating germ cells with immobilized peanut agglutinin lectin. Sertoli cells were then cultured for 6-10 days, forming a confluent layer with a cell viability of >83% and 74-77% purity. The contaminating cells were peritubular cells (4-6%), pachytene spermatocytes (4-5%), round spermatids (<2%), elongated spermatids (<1%), and degenerating germ cells (14.8%). The proportion of degenerating germ cells decreased from 14.8% to 8.6% between days 6 and 10 in culture. After a prestimulation culture period of 4 days, FSH treatment over a 2-day period resulted in a dose-related increase of inhibin with a median effective dose (ED50) value of 36.7+/-20.4 ng/ml in comparison with an ED50 value of 4.4+/-0.9 ng/ml obtained with immature Sertoli cell cultures from 20-day-old rats. Mature Sertoli cells, in contrast to immature Sertoli cells, were unresponsive to combined FSH + T treatment for the production of the cell adhesion protein N-cadherin. FSH treatment promoted the in vitro binding of round spermatids isolated from adult testis to adult Sertoli cells in coculture. It is concluded that mature Sertoli cells in culture are responsive to FSH in terms of inhibin production and round-spermatid binding. The lack of an FSH + T-induced increase in N-cadherin or round spermatid binding is attributed to either a reduced sensitivity, or an alteration in the regulation of mature Sertoli cells by FSH + T.     

Temperature and germ cell regulation of Leydig cell proliferation stimulated by Sertoli cell-secreted mitogenic factor: a possible role in cryptorchidism

Summary. Local control of Leydig cell morphology and function by seminiferous tubules was suggested in previous in vivo studies, especially those that used experimental cryptorchid rat testis as a model. These studies reported changes in morphology, increases in cell number and mitotic index and decreases in testosterone formation and luteinizing hormone/human chorionic gonadotropin receptor levels of Leydig cells. However, little is known about how these changes are mediated. We recently observed that a novel Sertoli cell-secreted mitogenic factor stimulated proliferation, decreased testosterone formation and luteinizing hormone/human chorionic gonadotropin receptor levels, and dramatically altered the morphology of Leydig cells in culture. In the present studies, we demonstrate that an increase in coculture temperature from 33 to 37 °C increased [³H]-thymidine incorporation (5.6- vs. 19.2-fold) and labelling index (4.3% vs. 15.8%), and accelerated proliferation (2.1- vs. 3.9-fold) of cultured immature Leydig cells. In addition, testosterone formation and luteinizing hormone/human chorionic gonadotropin receptor levels of Leydig cells cocultured with Sertoli cells were further decreased following a 4°C increase in coculture temperature. This elevation in culture temperature increased both the secretion of this factor by Sertoli cells and responsiveness of Leydig cells to this factor. In addition, the presence of germ cells, especially pachytene spermatocytes, inhibited the secretion of the mitogenic factor by Sertoli cells. These temperature- and germ cell-associated effects mimicked the morphological and functional changes of Leydig cells reported following experimental cryptorchidism. These observations suggest a possible role of this Sertoli cell-secreted mitogenic factor in explaining Leydig cell changes following experimental cryptorchidism.     

Acute adverse effects of the indenopyridine CDB-4022 on the ultrastructure of sertoli cells, spermatocytes, and spermatids in rat testes: comparison to the known sertoli cell toxicant Di-n-pentylphthalate (DPP)

Acute effects of CDB-4022 on testicular ultrastructure were determined. Rats were treated orally with vehicle or a maximally effective single dose of CDB-4022 or Di-n-pentylphthalate (DPP). Preserved testes were processed for transmission electron microscopy. Sertoli and germ cells of vehicle-treated rats demonstrated normal morphological characteristics. Disruption of Sertoli cell ultrastructure was apparent in CDB-4022-treated rats by 3 hours. A decrease in the presence of nucleoli, an increase in the amount and diameter of swollen smooth endoplasmic reticulum, and decreases in cytoplasmic ground substance were observed. The severity of these degenerative effects increased at 6 and 12 hours: Vacuoles were apparent; increased cellular debris, swollen mitochondria, and phagocytic structures were observed; and membranes became more disorganized. Similar ultrastructural changes were observed in the Sertoli cells of DPP-treated rats. By 3 hours, spermatocytes and spermatids were adversely affected by CDB-4022 treatment with swelling of the nuclear envelope. The Step 8 spermatids were especially noteworthy; chromatin was more diffuse and rarefied, the nuclear envelopes were incomplete or broken, and the position of the spermatid nucleus within the cell and relative to Sertoli cell cytoplasm was unusual. Fusion of spermatids to form giant cells was observed by 12 hours. CDB-4022 acts acutely on Sertoli cells to induce marked cellular rarefaction and degeneration, but not necrosis. A rapid and direct effect of CDB-4022 on spermatocytes and spermatids was observed. The antispermatogenic activity of CDB-4022 appears to be a consequence of direct effects on Sertoli and germ cells.