Evaluation of Changes in the Secretion of Immunoactive Inhibin by Adult Rat Seminiferous Tubules in Vitro as an Indicator of Early Toxicant Action on Spermatogenesis

1991 ◽  
Vol 16 (4) ◽  
pp. 710-724
Author(s):  
GARY ALLENBY ◽  
PAUL M. D. FOSTER ◽  
RICHARD M. SHARPE
Keyword(s):  
Seminiferous Tubules ◽  
Adult Rat

Intragonadal regulation of immune system functions

1990 ◽  
Vol 2 (3) ◽  
pp. 263 ◽  
Author(s):  
MP Hedger ◽  
JX Qin ◽  
DM Robertson ◽  
Kretser DM de
Keyword(s):  
Immune System ◽  
Immune Responses ◽  
Germ Cell ◽  
Conditioned Medium ◽  
Leydig Cells ◽  
Seminiferous Tubules ◽  
Interstitial Tissue ◽  
Short Term ◽  
Adult Rat

Immune responses within the mammalian gonads, and in particular the testis, are deficient in spite of adequate lymphatic drainage and the presence of lymphocytes and MHC II+ macrophages. There is considerable evidence from in vivo and in vitro studies that this 'suppression' of the immune system may be due, at least in part, to localized inhibition or regulation of normal lymphocyte and/or macrophage functions within the gonads. In the testis, both steroidal and non-steroidal products of the Leydig cells, including androgens, endorphins, and inhibin-related proteins, have been implicated in mediating this activity. In turn, a number of immune cell cytokines affect steroidogenic cell function in vitro. The studies described in this paper indicated that [3H]-thymidine incorporation by adult rat thymocytes in vitro was inhibited by conditioned medium collected from short-term incubations of Percoll-purified adult rat Leydig cells, but stimulated by testicular interstitial fluid and by conditioned medium collected from short-term incubations of adult rat seminiferous tubules. The factors responsible for these effects on thymocyte function appeared to be of large molecular weight, as they were retained by ultrafiltration membranes with exclusion limits of 10,000 or 30,000 daltons. It is hypothesized that an 'immunosuppressive' mechanism, principally mediated by non-steroidal factors secreted by the steroidogenic cells of the gonadal interstitial tissue, exists within the gonads in order to prevent activation of the immune system by germ cell antigens and growth factors associated with germ cell proliferation and differentiation. This mechanism probably acts in parallel with normal antigen-specific tolerance mechanisms operating at the gonadal level. As immune responses to germ cells are believed to be a significant causative factor in infertility, particularly in men, this represents an important area for further study.

Ethan-1,2-dimethanesulphonate reduces testicular oxytocin content and seminiferous tubule movements in the rat

1987 ◽  
Vol 112 (2) ◽  
pp. 311-NP ◽  
Author(s):  
H. D. Nicholson ◽  
R. T. S. Worley ◽  
S. E. F. Guldenaar ◽  
B. T. Pickering
Keyword(s):  
Leydig Cell ◽  
Seminiferous Tubule ◽  
Leydig Cells ◽  
Contractile Activity ◽  
Histological Study ◽  
Interstitial Cells ◽  
Seminiferous Tubules ◽  
Adult Rats ◽  
Adult Rat

ABSTRACT An oxytocin-like peptide is present in the interstitial cells of the testis, and testicular concentrations of oxytocin have been shown to increase seminiferous tubule movements in vitro. We have used the drug ethan-1,2-dimethanesulphonate (EDS), which depletes the Leydig cell population of the adult rat testis, to examine further the relationships between the Leydig cell, testicular oxytocin and tubular movements. Adult rats were injected i.p. with a single dose of EDS (75 mg/kg) or of vehicle (25% dimethyl sulphoxide). Histological study 3 and 10 days after treatment with EDS showed a reduction in the number of interstitial cells, and levels of oxytocin immunoreactivity were undetectable by radioimmunoassay. Immunostaining revealed very few oxytocin-reactive cells. Spontaneous contractile activity of the seminiferous tubules in vitro was also dramatically reduced, but could be restored by the addition of oxytocin to the medium. Four weeks after EDS treatment, the interstitial cells were similar to those in the control animals both in number and in immunostaining; immunoassayable oxytocin was present and tubular movements were normal. The EDS effect, seen at 3 and 10 days, was not altered by daily treatment with testosterone. However, repopulation of the testes with oxytocin-immunoreactive cells was not seen until 6 weeks in the testosterone-treated animals. We suggest that the Leydig cells are the main source of oxytocin immunoreactivity in the testis and that this oxytocin is involved in modulating seminiferous tubule movements and the resultant sperm transport. The results also imply that testosterone does not play a major role in controlling tubular activity in the mature rat. J. Endocr. (1987) 112, 311–316

scholarly journals The expression and regulation of Bcl-2-related ovarian killer (Bok) mRNA in the developing and adult rat testis

2001 ◽  
pp. 771-778 ◽  
Author(s):  
JS Suominen ◽  
W Yan ◽  
J Toppari ◽  
A Kaipia
Keyword(s):  
Mrna Expression ◽  
Northern Hybridization ◽  
Seminiferous Tubules ◽  
Testicular Development ◽  
Rat Testis ◽  
Adult Rat ◽  
Before And After ◽  
Hybridization Intensity ◽  
Pachytene Spermatocytes

OBJECTIVE: To study the role of Bcl-2-related ovarian killer (Bok) in the regulation of apoptosis in the testis of developing and adult rat. METHODS: Bok mRNA expression was analyzed by Northern hybridization before and after culturing rat seminiferous tubules in vitro. Seminiferous tubules were cultured with different hormones and growth factors. Changes in the expression level of Bok mRNA during testicular development was analyzed by Northern hybridization. Localization of Bok mRNA was verified by in situ hybridization. RESULTS: Bok mRNA was highly expressed in the rat testis, varying during development. Highest expression levels were found in immature rats. Highest hybridization intensity appeared to be in spermatogonia, pachytene spermatocytes and Sertoli cells. Treatment with FSH was able to inhibit spontaneous increase of Bok mRNA expression that occurred in the defined stages of the rat seminiferous epithelium. CONCLUSIONS: FSH protects germ cells from apoptosis and this protective effect may at least partly be due to the inhibition of Bok gene expression. The amount of apoptosis varies during testicular development and highest expression of Bok mRNA occurs at the time of apoptosis, suggesting a possible role for Bok in its regulation.

scholarly journals Stage-related differences in rat seminiferous tubule contractility in vitro and their response to oxytocin

1998 ◽  
Vol 157 (2) ◽  
pp. 251-257 ◽  
Author(s):  
GC Harris ◽  
HD Nicholson
Keyword(s):  
Seminiferous Tubule ◽  
Contractile Activity ◽  
Control Period ◽  
Time Lapse ◽  
Seminiferous Tubules ◽  
Computer Assisted ◽  
Adult Rat ◽  
Specific Effects ◽  
Assisted Analysis

Oxytocin (OT) is present in the mammalian testis and has been shown to play a role in the modulation of seminiferous tubule contractility and steroidogenesis. However, stage-specific effects of the peptide have not been previously investigated. In this study, computer-assisted analysis and time-lapse videomicrography were used to investigate basal contractility and the response to OT of seminiferous tubules at specific stages of the spermatogenic cycle. Adult rat testes were placed in fresh oxygenated DMEM F12 medium, decapsulated, and the tubules gently teased apart. Stages were identified by transillumination and a 10 mm section of tubule at each of stages IV-V, VII-VIII and XIII-I was placed in a microslide chamber and perifused with medium. After a control period of 3 h, OT (2 nM) was given for 1 h, followed by another control period of 1 h. The experiment was repeated using tubules from different rats and data were analysed to give arbitrary units of tubule contractility. Contractility was observed in all the tubules studied and the contractile activity was shown to vary depending on the stage of the spermatogenic cycle. Mean basal contractility at stages VII-VIII, the time when sperm are shed from the epithelium, was significantly lower than that at stages IV-V and XIII-I. The response of the tubules to OT was also stage-dependent, with the peptide producing the largest increases in contractile activity at stages VII-VIII and having no effect at stages IV-V. We postulate that these stage-specific differences in basal and OT-stimulated contractility may be important in co-ordinating the movement of developing germ cells towards the lumen of the seminiferous epithelium and in the process of spermiation.

Epidermal growth factor increases inhibin synthesis by isolated segments of rat seminiferous tubules

1989 ◽  
Vol 123 (2) ◽  
pp. 213-219 ◽  
Author(s):  
G. F. Gonzales ◽  
G. P. Risbridger ◽  
D. M. de Kretser
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Cyclic Amp ◽  
Phorbol Esters ◽  
Seminiferous Tubules ◽  
Dibutyryl Cyclic Amp ◽  
Adult Rats ◽  
Adult Rat ◽  
Epidermal Growth

ABSTRACT The effect of epidermal growth factor (EGF) on the production of immunoreactive inhibin by adult rat isolated seminiferous tubules in vitro has been investigated. EGF (0·1–1000 ng/ml) added to cultures of seminiferous tubules from adult rats caused a dose-dependent increase in inhibin content in the tubules without changing the amount secreted into the media. However, after continuous stimulation with EGF for periods in excess of 5 days, an increase in inhibin secretion was observed. In the presence of 10 and 100 ng FSH/ml, EGF (10 ng/ml) produced a further increment in the inhibin content of the tubules, but this effect was not found with FSH concentrations of 500 or 1000 ng/ml. EGF also increased the tubule content of inhibin after the addition of 100 μg dibutyryl cyclic AMP/ml but no effect of EGF was observed on the FSH- or dibutyryl cyclic AMP-induced secretion of inhibin into the medium. The effect of EGF on inhibin content in the tubules was partially suppressed by the addition of 4β-phorbol-12β-myristate-13α-acetate (20 ng/ml). Insulin (1–100 ng/ml) decreased basal inhibin secretion without changing the inhibin content of tubules and this effect was antagonized by EGF (10 ng/ml) with insulin doses of 1–50 ng/ml whereas, at 100 ng/ml, the effect of EGF on tubule inhibin content was reversed. The addition of EDTA (2 mmol/l) resulted in an inhibition of basal and EGF-induced inhibin production. These data demonstrate a stimulatory effect of EGF on inhibin production by isolated seminiferous tubules which is inhibited by insulin and phorbol esters, both stimulators of protein kinase C activity. Journal of Endocrinology (1989) 123, 213–219

Stimulatory and inhibitory factors of Leydig cell steroidogenesis are secreted simultaneously by the rat seminiferous tubules and do not affect Leydig cell inhibin production in vitro

1994 ◽  
Vol 6 (6) ◽  
pp. 693 ◽  
Author(s):  
JR McFarlane ◽  
Kretser DM de ◽  
GP Risbridger
Keyword(s):  
Conditioned Medium ◽  
Leydig Cell ◽  
Leydig Cells ◽  
Seminiferous Tubules ◽  
Low Doses ◽  
Adult Rat ◽  
Testosterone Production ◽  
Significant Reversal ◽  
The Mean

The effect of conditioned medium from rat seminiferous tubules (at Stages VII-VIII and Stages IX-VI) cultured with or without follicle-stimulating hormone (FSH) on the production of testosterone and immunoactive inhibin by Leydig cells was examined. Low doses of conditioned medium from unstimulated tubules at Stages VII-VIII significantly (P < 0.05) increased the mean testosterone production to greater than 31 +/- 11% over that achieved with luteinizing hormone (LH) alone. At the highest dose, the conditioned medium significantly inhibited (P < 0.05) LH-stimulated testosterone production by 13 +/- 7%. Low doses of conditioned medium from unstimulated tubules at Stages IX-VI increased the mean testosterone production to 22 +/- 10%, whereas at higher doses, a significant reversal in the stimulation occurred although not to the same extent as that found with medium from tubules at Stages VII-VIII. Conditioned medium from FSH-stimulated tubules at Stages VII-VIII and Stages IX-VI, significantly increased testosterone production to 39 +/- 7% and 31 +/- 13% respectively. Immunoactive inhibin production by the Leydig cells remained unaffected by exposure to conditioned medium from FSH stimulated and unstimulated tubules at Stages VII-VIII and Stages IX-VI. The data demonstrate that tubule culture medium contains FSH-modulated activities which can specifically stimulate and inhibit testosterone synthesis by adult rat Leydig cells in vitro and therefore explains the contradictory reports in the literature.

Immunoenzymatic demonstration of the simultaneous presence of transferrin, hemopexin and albumin in a same hepatocyte and their ultrastructural localization

1978 ◽  
Vol 36 (2) ◽  
pp. 88-89
Author(s):  
M. Kraemer ◽  
J. Foucrier ◽  
J. Vassy ◽  
M.T. Chalumeau
Keyword(s):  
Plasma Proteins ◽  
Rat Hepatocytes ◽  
Ultrastructural Localization ◽  
Carrier Proteins ◽  
Normal Cells ◽  
Adult Rat ◽  
Adult Rat Hepatocytes ◽  
Monospecific Antisera ◽  
Different Levels

Some authors using immunofluorescent techniques had already suggested that some hepatocytes are able to synthetize several plasma proteins. In vitro studies on normal cells or on cells issued of murine hepatomas raise the same conclusion. These works could be indications of an hepatocyte functionnal non-specialization, meanwhile the authors never give direct topographic proofs suitable with this hypothesis.The use of immunoenzymatic techniques after obtention of monospecific antisera had seemed to us useful to bring forward a better knowledge of this problem. We have studied three carrier proteins (transferrin = Tf, hemopexin = Hx, albumin = Alb) operating at different levels in iron metabolism by demonstrating and localizing the adult rat hepatocytes involved in their synthesis.Immunological, histological and ultrastructural methods have been described in a previous work.

scholarly journals Exendin-4 Promotes Schwann Cell Survival/Migration and Myelination In Vitro

2021 ◽  
Vol 22 (6) ◽  
pp. 2971
Author(s):  
Shizuka Takaku ◽  
Masami Tsukamoto ◽  
Naoko Niimi ◽  
Hideji Yako ◽  
Kazunori Sango
Keyword(s):  
Phosphatidyl Inositol ◽  
Specific Protein ◽  
Myelin Protein ◽  
Drg Neurons ◽  
Antibody Treatment ◽  
Pi3k Inhibitor Ly294002 ◽  
Adult Rat ◽  
Drg Neuron ◽  
Peripheral Nerve Lesions

Besides its insulinotropic actions on pancreatic β cells, neuroprotective activities of glucagon-like peptide-1 (GLP-1) have attracted attention. The efficacy of a GLP-1 receptor (GLP-1R) agonist exendin-4 (Ex-4) for functional repair after sciatic nerve injury and amelioration of diabetic peripheral neuropathy (DPN) has been reported; however, the underlying mechanisms remain unclear. In this study, the bioactivities of Ex-4 on immortalized adult rat Schwann cells IFRS1 and adult rat dorsal root ganglion (DRG) neuron–IFRS1 co-culture system were investigated. Localization of GLP-1R in both DRG neurons and IFRS1 cells were confirmed using knockout-validated monoclonal Mab7F38 antibody. Treatment with 100 nM Ex-4 significantly enhanced survival/proliferation and migration of IFRS1 cells, as well as stimulated the movement of IFRS1 cells toward neurites emerging from DRG neuron cell bodies in the co-culture with the upregulation of myelin protein 22 and myelin protein zero. Because Ex-4 induced phosphorylation of serine/threonine-specific protein kinase AKT in these cells and its effects on DRG neurons and IFRS1 cells were attenuated by phosphatidyl inositol-3′-phosphate-kinase (PI3K) inhibitor LY294002, Ex-4 might act on both cells to activate PI3K/AKT signaling pathway, thereby promoting myelination in the co-culture. These findings imply the potential efficacy of Ex-4 toward DPN and other peripheral nerve lesions.

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