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1.
Thirty-four pairs of testes from wild adult raccoon dogs (Nyctereutes procyonoides) were obtained between September 2000 and May 2003. The cellular localization of the inhibin alpha and inhibin/activin (betaA and betaB) subunits in wild raccoon dog testes was investigated. The testicular weight and size and seminiferous tubule diameters were measured. There were marked seasonal variations in testicular weight and size and seminiferous tubule diameters, with values relatively low in September and high in March. Spermatogonia and primary spermatocytes were observed in September, and spermatogonia, spermatocytes, and round spermatids were present in January. All types of spermatogenic cells, including mature spermatozoa, were found in March, indicating that the breeding season is around March in Japan. Thereafter, spermatogonia and degenerating spermatocytes were observed in April. The sections of testes were immunostained by the avidin-biotin-peroxidase complex method (ABC) using polyclonal antisera raised against porcine inhibin alpha, inhibin/activin betaA and inhibin/activin betaB. The inhibin alpha and inhibin/activin (betaA and betaB) subunits were only expressed in Leydig cells in September. On the other hand, the inhibin alpha, betaA, and betaB subunits were observed in Leydig cells and Sertoli cells, but not in germ cells, in March. These results suggest that the testes of wild raccoon dogs have the ability to synthesize inhibins, and the cellular localization of inhibin/activin subunits showed season-related changes in the breeding and non-breeding seasons.  相似文献   

2.
The objective of this study was to investigate the seasonal changes in spermatogenesis and the immunolocalization of the inhibin alpha and inhibin/activin (betaA and betaB) subunits during the breeding and non-breeding seasons in the wild male ground squirrel. The testicular weight and size and seminiferous tubule diameter were measured, and histological observations of testes were performed. The sections of the testes were immunostained by the avidin-biotin-peroxidase complex method (ABC) using polyclonal antisera raised against porcine inhibin alpha, inhibin/activin betaA and inhibin/activin betaB during the breeding and non-breeding seasons. There were marked variations in testicular weight and size and seminiferous tubule diameter between the breeding and non-breeding seasons, and all types of spermatogenic cells, including spermatozoa, were found in the breeding season. In addition, immunoreactivity was also detected for the inhibin alpha, betaA and betaB subunits in Sertoli and Leydig cells during the breeding season, but immunostaining was only present for the inhibin alpha and inhibin/activin betaB subunits in Sertoli cells during the non-breeding season. These results suggest that seasonal changes in testicular weight and size and seminiferous tubule diameter of wild ground squirrels are correlated with changes in spermatogenesis, and the cellular localization of the inhibin/activin subunits showed season related changes in the breeding and non-breeding seasons.  相似文献   

3.
The differential localization of the inhibin beta subunits betaA and betaB in the testis of adult bull was studied using specific monoclonal and polyclonal primary antibodies. Inhibin betaA- and betaB-subunits were localized only in the Sertoli cells. The inhibin betaA-subunit was observed in the cytoplasm while the betaB-subunit was localized in the nucleus. No specific findings depending on spermatogenic stages were observed among the seminiferous tubules. Moreover, the inhibin alpha-subunit was not detected in the testis of the bulls. In addition, no inhibin subunits were detected in the Leydig cells and spermatogenic cells. These findings indicate the presence of betaA- and betaB-subunits in the bull, which may suggest a possibility that activin is produced and/or stored in the Sertoli cells and regulates spermatogenesis in an autocrine/paracrine manner. Moreover, the inhibin betaB-subunit may be produced in the nucleus but the functional meaning of this is not yet clear.  相似文献   

4.
The ontogeny of testicular inhibin/activin in ducks was investigated. Testicular localization of three inhibin/activin subunits (α, βA and βB) was determined in embryonic and newly hatched ducks from 12 days of incubation to 1 day of age, in immature ducks and in adult ducks. In the duck embryonic testis, positive α‐subunit immunostaining was first detected in the Leydig cells and Sertoli cells on day 15 of incubation, whereas βA‐subunit and βB‐subunit immunostaining were found in Sertoli cells and primary germ cells on day 18 of incubation. In 1 month old ducks, intense staining of α‐subunit was present in the seminiferous epithelium consistent with localization in Sertoli cells and primary germ cells, and the immunostaining of the βA‐ and βB‐subunit was also present in Sertoli cells and primary germ cells. Specific immunostaining with inhibin/activin α‐, βA‐ and βB‐subunits antisera occurred in Sertoli cells in the adult duck testes. In conclusion, it was shown that, in the duck testis, the majority of α‐, βA‐ and βB‐subunits are colocalized in Sertoli cells with a certain degree of staining in germ cells and the α‐subunit is present in Leydig cells of embryonic testes before day 18 of incubation. These results indicate that Sertoli cells and possibly germ cells in the embryonic testes of late stage of incubation and newly hatched ducks, immature ducks and mature ducks may produce bioactive inhibin dimers, inhibin A and inhibin B, as a possible regulator of follicle‐stimulating hormone secretion. Free inhibin/activin subunits and their dimers may also play an autocrine/paracrine role in the development of the testis and spermatogenesis. Furthermore, early onset of the α‐subunit in duck testes indicates that it may have an autocrine/paracrine effect on steroid hormones, which is important for sex differentiation.  相似文献   

5.
The objective of this study was to investigate the cellular immunolocalization of inhibin a and inhibin/activin (β(A) and β(B)) subunits in the muskrat testes and scented glands during the breeding season. Inhibin α and inhibin/activin (β(A) and β(B)) subunits were expressed in Sertoli cells and Leydig cells of testes and glandular cells of scented glands, respectively. Also, positive signals of inhibin α and inhibin/activin (β(A) and β(B)) subunits by Western blotting were both observed in testicular and scented glandular tissues. These results suggested that the testes and scented glands of the muskrats had the ability to synthesize inhibins and activins and that activins and inhibins might play an important role in testicular and scented glandular function in muskrats.  相似文献   

6.
The expression of activin and inhibin has been demonstrated in the hypothalamus, but their physiological roles in the brain remain to be elucidated. In the present study, involvement of activin and inhibin in the regulation of food and water intake was examined. Male rats were deprived of food or water for 12 and 60 hr, and mRNA levels of activin/inhibin alpha, betaA and betaB subunits in the hypothalamus were estimated by RT-PCR. Gene expression of alpha subunit transiently decreased at 12 hr of food deprivation, while it did not change during water deprivation. Food and water deprivation for 60 hr increased mRNA levels of betaA and betaB subunits, respectively. These results indicated that gene expression of each subunit was independently regulated. Injection of activin A (0.5 and 4.0 microg) into the third ventricle decreased food intake. Water intake was suppressed by 4.0 microg, but not 0.5 microg, of activin A. Intracerebroventricular injection of inhibin A (0.5 and 4.0 microg) decreased water intake in a dose dependent manner without affecting food intake, suggesting that inhibin could act independently of activin. Taken together, it is suggested that activin and inhibin take part in the central regulation of nutrient and fluid balance, though further study is needed to determine precise molecular species involved.  相似文献   

7.
The objective of this study was to investigate the changes in secretion of inhibin and cellular localization of the inhibin alpha and inhibin/activin (beta(A) and beta(B)) subunits in male Japanese quail from 1 to 7 weeks after hatching. The post-hatch profile of plasma luteinizing hormone (LH), immunoreactive (ir) inhibin and testosterone were measured by radioimmunoassay. Testes were immunostained by the avidin-biotin-peroxidase complex method (ABC) using polyclonal antisera raised against inhibin alpha, inhibin/activin beta(A) and inhibin/activin beta(B) from one week of age to sexual maturity. Testicular weight increased gradually until 4 weeks and abruptly increased from 5 weeks of age onwards. The plasma concentrations of LH and ir-inhibin increased significantly at 5 weeks of age, and the plasma concentration of testosterone increased significantly at 6 weeks of age. Pituitary contents of LH showed a steady increase until 6 weeks of age and then abruptly increased at 7 weeks of age. Coincident to the increase in plasma testosterone, the testicular contents of testosterone significantly increased from 5 weeks through sexual maturity. Immunohistochemically, localization of the inhibin/activin alpha, beta(A) and beta(B) subunits was found in the Sertoli and Leydig cells at all ages of development from one week of age to sexual maturity. These results suggest that Sertoli and Leydig cells are the major source of inhibin secretion during development in male Japanese quail.  相似文献   

8.
The seasonal spermatogenesis and localization of inhibin/activin subunits (alpha, betaA, betaB) in the testes of wild ground squirrel has been previously described; however, the expression pattern of activin receptors and cytoplasmic signaling SMADs has not been detected in any seasonal breeders. The objective of this study was to investigate the abundance and cellular localization of activin signaling components in testes of the wild ground squirrel during the breeding and nonbreeding seasons. The immunolocalizations of ActRIIB (activin type II receptor B) and activin-related SMADs (phospho-SMAD2/3, SMAD4 and SMAD7) were observed by immunohistochemistry. Total proteins were extracted from testicular tissues in the breeding and nonbreeding seasons and were used for Western blotting analysis for ActRIIB and SMADs. Immunoreactivities of activin signaling components were greater in the testes of the breeding season, and then decreased to a relatively low level in the nonbreeding season. ActRIIB and related SMADs were widely spread in the active testes, while spermatogonia were the predominant cellular sites of activin signal transduction during arrested spermatogenesis. The dynamic regulation of activin type II receptor and SMADs indicated that the activin signal pathway played an important paracrine role in seasonal spermatogenesis of the wild ground squirrel. Furthermore, the distinct localizations and immunoreactivity of ActRIIB and SMADs might suggest different functions of activin in seasonal spermatogenesis.  相似文献   

9.
Immunohistochemical detection of inhibin-alpha, -betaA and -betaB chains and 3beta-hydroxysteroid dehydrogenase (HSD) was carried out on primary testicular tumors from 15 dogs and normal testes from three adult dogs. Histopathologically, the tumors were composed of three types: Leydig cell tumors in five dogs, Sertoli cell tumors in five dogs, and seminoma in five dogs. In normal testes, immunostaining against inhibin-alpha, -betaA, and -betaB chains and 3beta-HSD revealed positive reactivity in the cytoplasm of Leydig cells. In testicular tumors, immunoreactive cells against inhibin-alpha, -betaA, and -betaB chains and 3beta-HSD were localized in all Leydig cell tumors but not in any Sertoli cell tumors or seminomas. The results of radioimmunoassay for plasma inhibin in dogs with Leydig cell tumors showed higher concentrations than those in dogs with Sertoli cell tumors and seminomas and those in normal dogs. The concentration of inhibin in the plasma was markedly decreased by the surgical removal of the Leydig cell tumor in one dog. Our findings suggest that inhibin is synthesized by normal and neoplastic Leydig cells in the canine testis, and the secreted inhibin may be inhibin A and inhibin B.  相似文献   

10.
Gonadal function in the male golden hamster (Mesocricetus auratus) was investigated during exposure to a short photoperiod condition. Within 3 weeks of exposure to the short photoperiod condition, FSH and testosterone in the plasma significantly decreased, and subsequently immunoreactive (ir)-inhibin significantly decreased. Testicular contents of ir-inhibin and testosterone, and pituitary contents of LH and FSH also significantly decreased by 3 weeks with regression of weight of testes, epididymis and seminal vesicles and sperm head count. Circulating LH varied but not significantly. Thereafter, all reproductive parameters and secretion of LH, FSH, ir-inhibin and testosterone gradually recovered after 17 weeks of exposure even though animals continued to be subjected to the short photoperiod condition. Plasma concentrations of inhibin B and inhibin pro-alphaC were detectable and were significantly decreased after 15 weeks of exposure to the short photoperiod, but their levels were still detectable. Immunopositive reaction of inhibin alpha and betaB subunits was found in Sertoli cells and Leydig cells in the regressed testes of animals subjected to short photoperiod as was also seen in animals before exposure to the short photoperiod. Although the spermatogenic cycle was suppressed like prepubertal animals, the present study showed that the testicular recovery, so-called refractoriness, is functionally different from the developing stage of immature animals, especially with regard to inhibin secretion. The present results showed that changes in FSH preceded changes in inhibin during the regression and recovery phases, indicating that FSH is a major regulatory factor of inhibin secretion in male golden hamsters. The present study also demonstrated that regressed testes still secrete a small amount of bioactive inhibin during exposure to a short-photoperiod condition.  相似文献   

11.
The localization of alpha, beta A and beta B subunits of inhibin/activin polypeptides was studied in the ovary and testis of sexually mature, immature, and embryonic rats. Specific staining with these three subunits was also evident in the oocytes from embryonic to mature female rats. This result suggests that inhibin- and activin-like substances may be produced in the oocytes and these substances may play a role in the oocyte growth and differentiation. Judging from the intensity of immunoreaction in mature female rats, the three subunits should be produced more abundantly in luteal cells than in the granulosa cells. Immunoreactive alpha, beta A and beta B subunits were observed in the cummulus oophorous in the morning (11:00), but not in the evening (23:00) on proestrus. The results are in well agreement with the previous report that inhibin alpha and beta A subunit mRNA signals decline on proestrus evening. It is supposed that the cyclic change may be related with physiological phenomena prior to the ovulation, such as primary gonadotropin surges, loss of cummulus-oocyte gap junctions, or germinal vesicle breakdown. In both germ cells and Sertoli cells of the testis, alpha, beta A and beta B subunits were more abundant in the embryonic rat than in the mature rat. Although clear reactions with beta A and beta B subunits were detected in Leydig cells, alpha subunit was not detectable in the cells throughout the developmental stages examined.  相似文献   

12.
Activins and inhibins are regulatory proteins of the reproductive function. Inhibins antagonise the activin signalling at different levels and are responsible for the negative feedback in the regulation of the release of pituitary follicle stimulating hormone (FSH), which, in turn, is promoted by locally produced activins. In the canine ovary, both peptides are expressed by developing follicles and corpora lutea. Activins may play a stimulatory role in follicular development, promoting the aromatase function; inhibins modulate these processes and suppress the hyperplasic/neoplastic stimuli. Activins are required for ovulation and corpus luteum formation, while inhibins stimulate progesterone synthesis. The exclusive production of alpha‐inhibin by granulosa cells allows the peptide to be used as marker to identify canine ovarian stromal tumours by immunohistochemistry. In the male, activins are powerful morphogenetic factors in the foetal testis. In the adult, they display a modulating action on spermatogenesis and Sertoli cell function. Inhibins, produced mainly by Leydig cells, promote testosterone secretion. Canine testicular tumours, such as Leydig, Sertoli and granulosa cell tumours (GCTs), may express inhibin subunits and produce high circulating levels of these glycoproteins. In the canine prostate, activins inhibit epithelium proliferation, antagonising androgen effects, but they are synthesised under androgenic stimulus.  相似文献   

13.
In the present study, the expression of inhibin/activin subunits in the mouse ovary from 13 days post-coitus (dpc) to 30 days postpartum (dpp) was investigated. Circulating FSH, LH, inhibin A, and inhibin B in neonatal to 30 dpp ovaries were measured. Inhibin/activin subunits (alpha, beta(A), beta(B) ) were weakly stained in 13 dpc ovarian stromal cells and increased with age. Inhibin alpha subunit was immunolocalized in follicular granulosa cells at each developmental stage. In 30 dpp ovaries, several large antral follicles were strongly stained for inhibin alpha subunit. Inhibin beta(A) subunit was weakly immunolocalized in granulosa cells until 20 dpp. Moreover, 2 to 3 antral follicles from 20 to 30 dpp were strongly stained for inhibin beta(A) subunit. There was relatively high immunoactivity for inhibin beta(B) subunit in neonatal to 30 dpp mouse ovaries. All three inhibin subunits were stained in theca-interstitial cells from 15 dpp onward. RIA data showed that a temporal increase in circulating FSH occurred around 10 dpp, while the plasma concentrations of LH were sustained at a relatively higher level from 8 to 15 dpp. Inhibin B was detectable in circulation early at 1 dpp (day of birth), and a clear increase in inhibin B occurred around 8 dpp. Circulating inhibin B gradually increased from 20 dpp to 30 dpp, indicating a negative correlation with FSH. Inhibin A levels were only measured on 25 and 30 dpp, and the levels were low. These results suggest that inhibins play an important role in early folliculogenesis in mice. In addition, inhibin B seems to be the main functional isoform from the neonatal to prepubertal stage in the mouse ovary.  相似文献   

14.
Formalin-fixed, paraffin-embedded sections from 32 canine pairs of testes were immunohistochemically examined for Inhibin-α (INHα). Samples were subdivided into two groups (group 1, neonates; group 2, puppies and adults) and results statistically compared. Inhibin-α was significantly expressed only in Sertoli cells of neonatal testes, while in Leydig cells it was expressed without significant difference between groups. These results suggest that, in dogs, INHα expression switches from Sertoli to Leydig cells during testicular maturation and that, in adult, Leydig cells represent the main source of INHα.  相似文献   

15.
To clarify the morphological and immunohistochemical characteristics in mares with granulosa theca cell tumor (GTCT), the localization of inhibin subunits (alpha, betaA, betaB) and aromatase in the granulosa cell layers and theca layers in the ovarian follicles were determined by immunohistochemical staining. The follicles were obtained from the ovaries of 6 mares with GTCT and 4 normal mares as controls. Immunohistochemically, inhibin alpha-subunit was localized in the granulosa cells of all follicles showing different sizes in all GTCT cases and betaA- subunit was localized in two GTCT cases in all sized follicles. But inhibin betaB- subunit and aromatase were not localized in GTCT cases. On the other hand, inhibin alpha-, betaA-, and betaB-subunits and aromatase were localized in the large and medium sized follicles, but inhibin betaA- and betaB-subunits and aromatase were not stained in the small sized follicles in normal cases. These findings suggest that some mares with GTCT can secrete dimeric inhibin (inhibin A), but all GTCT cases cannot secrete inhibin B. By the results of aromatase staining it is clear that testosterone is not converted into estradiol due to the lack of aromatase in the GTCT follicles.  相似文献   

16.
To clarify the cellular source and secretory pattern of inhibin in the Japanese quail during follicular development, the plasma concentrations of immunoreactive (ir) inhibin were measured from 1 to 7 weeks after hatching. Localization of the inhibin/activin alpha, beta A and beta B subunits was investigated by immunohistochemistry. To monitor development of the pituitary and ovarian functions, the plasma luteinizing hormone (LH) and progesterone concentrations were also measured. Ovarian weight increased gradually until 6 weeks of age and then abruptly increased at 7 weeks of age just at the onset of egg production. Plasma concentrations of LH increased significantly at 6 weeks of age. The plasma concentrations of ir-inhibin and progesterone and the pituitary contents of LH also increased significantly at 7 weeks of age. Immunohistochemically, the inhibin/activin alpha, beta A and beta B subunits were localized in the granulosa cells of all follicles during different stages of development from 1 to 7 weeks after hatching. The inhibin alpha, beta A and beta B subunits were also found in the interstitial cells but not theca cells of all follicles. These results demonstrated that the plasma concentrations of ir-inhibin of the female Japanese quails rose with ovarian development. The immunohistochemical results suggested that granulosa and interstitial cells are the major source of ovarian inhibins in female Japanese quails.  相似文献   

17.
The ultimate goal of this study was to establish an in vitro system to produce sperms. To pursue this goal, immature porcine testicular cells were cultured in stereostructural form and cultured testicular cord was investigated morphologically. At 4 weeks of age, the seminiferous tubules of the porcine testes consisted of undifferentiated germ cells (gonocytes and undifferentiated spermatogonia) and immature Sertoli cells. The interstitial tissue was largely occupied by Leydig cells. The testes were enzymatically digested, and the dispersed cells were encapsulated with alginate either immediately or after freeze-thawing. The resulting testicular cell cords were cultured for up to 10 weeks. After 2 weeks of culture, Sertoli cells, which were identified by their inhibin-positive reaction in immunohistochemistry, and Leydig cells, which were identified by their morphological characteristics, were observed in the cords. Neither undifferentiated nor differentiated types of germ cells were detected. The number of cells in the cords progressively decreased during the culture period. In order to discover the fate of the Sertoli cells, the level of inhibin in the spent media was determined. Inhibin in the media was at a detectable level after 2 days of culture. The levels increased and peaked at 2 weeks. When frozen-thawed testicular cells were applied to the culture, the peak level was maintained for over 8 weeks, in contrast to the gradual decrease of inhibin level when fresh cells were cultured. These results indicate that the culture conditions can sustain the survival of Sertoli cells. Further improvement is required for proliferation and differentiation of germ cells.  相似文献   

18.
The establishment of equine pregnancy is a unique and long process during which a series of physical and possibly biochemical interactions are required between the conceptus and uterus. In this study, we investigated the expression pattern of inhibin/activin subunits in the uterus during early pregnancy. The uteri from four adult mares on cyclic day 13 or pregnancy day 25 were obtained. Immunohistochemical experiments suggested that inhibin/activin subunits were immunolocalized in the luminal and glandular epithelium on pregnancy day 25. In addition, the inhibin α and inhibin/activin βB subunits were not detected, and inhibin/activin βA subunit was detected, in the luminal and glandular epithelium on cyclic day 13. Real‐time polymerase chain reaction and Western blotting results for the inhibin/activin subunits suggested a significant increase in the expression of inhibin/activin subunit βB and a significant decrease in the expression of inhibin/activin subunit βA on pregnancy day 25 compared with those on cyclic day 13. Enzyme‐linked immunosorbent assays suggested a significant decrease in the concentration of activin A in endometrium extracts from cyclic day 13 to pregnancy day 25. These results suggest that inhibins or activins synthesized in the uterus, as endocrine factors and necessary nutriments, have different expression patterns and may play different, important roles during early embryonic development of the equine.  相似文献   

19.
We tested the hypothesis that acute pre-natal exposure to high levels of synthetic glucocorticoid (betamethasone) would alter fetal testicular development through actions on gonadal glucocorticoid receptors (GRs). Pregnant Merino ewes bearing singleton male fetuses (n = 24) were allocated randomly among four equal groups to be injected intramuscularly with saline or betamethasone (0.5 mg/kg) either on day 109 of gestation or on both day 109 and day 116 of gestation. Fetal testes were collected at post-mortem, 5 days after each treatment. The volume of interstitial tissue and the volume, length and diameter of the sex cords were measured, and Sertoli cells and gonocytes were counted. For cord volume and interstitial tissue volume, control testes demonstrated maturational changes as fetal age advanced from 109 to 116 days of gestation. For that period, the single injection of betamethasone significantly reduced Leydig cell proliferation (P < 0.05), but had no effect on Sertoli cell numbers. Immunohistochemistry was used to localize GR and proliferating cell nuclear antigen in testicular cells. GR immunoexpression in Leydig cells was higher in fetuses exposed to betamethasone at 109 days of gestation than in control fetuses. Sertoli cells showed low levels of GR. It was concluded that, during mid-gestation, a brief period of glucocorticoid treatment could affect testicular development in male sheep fetuses. The mechanism probably involves direct effects on Leydig cells, as these cells express extra-GR in response to the treatment. Sertoli cells seem to produce less GR than Leydig cells, perhaps explaining their lack of response to betamethasone. These outcomes may have important implications for future fertility in male offspring.  相似文献   

20.
Analysis of the function of activin betaC subunit using recombinant protein   总被引：2，自引：0，他引：2  
Activins, TGF-beta superfamily members, have multiple functions in a variety of cells and tissues. Additional activin beta subunit genes, betaC and betaE, have been identified in humans and rodents. To explore the role of activin betaC subunit, we generated recombinant human activin C using Chinese hamster ovary cells. Recombinant activin C from the conditioned medium was purified by consecutive hydrophobic, size-exclusion, and high performance liquid chromatography. SDS-PAGE and Western blot analysis of the purified protein revealed that activin C formed disulfide bridges. However, activin C had no effect on the proliferation of cultured liver cells. Furthermore, there were no significant differences in erythroid differentiation and follicle stimulating hormone secretion in vitro. It was also shown that immunoreactive bands indicated the hetrodimer of activin betaC, and inhibin alpha subunits were detected in the conditioned medium from the activin C-producing cells, which were stably transfected with inhibin alpha subunit cDNA. This suggests that activin betaC subunit may have been present and that it may exert its effect as inhibin C.  相似文献   

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