Hormone-induced resistance of rat Leydig cells to the cytotoxic effects of ethane-1,2-dimethane sulphonate

1992 ◽  
Vol 134 (1) ◽  
pp. 85-NP ◽  
Author(s):  
K. J. Teerds ◽  
D. G. de Rooij ◽  
C. J. G. Wensing ◽  
F. F. G. Rommerts

ABSTRACT Several studies have shown that the cytotoxic agent ethane-1,2-dimethane sulphonate (EDS) specifically destroys Leydig cells in the adult rat testis. It has also been reported that when rats are pretreated with human chorionic gonadotrophin (hCG), administration of EDS does not result in the complete destruction of the Leydig cell population. It has been suggested that hCG pretreatment 'protects' Leydig cells against the cytotoxic action of EDS. In the present study the underlying principles for this resistance to the cytotoxic effects of EDS have been investigated. Within 48 h of the start of daily hCG treatment the number of nuclear profiles of Leydig cells (henceforth called relative number of Leydig cells) had increased from 1014 ± 40 to 1368 ± 30 cells per 1000 Sertoli cell nuclei. Previous experiments have indicated that these newly formed Leydig cells probably develop from differentiating Leydig cell precursors. When EDS is administered concomitantly with the third injection of hCG (2 days after the start of hCG treatment), the relative number of Leydig cells surviving EDS treatment was 388 ± 52 per 1000 Sertoli cells. Hence, there is a similarity between the increase in the relative number of Leydig cells after 2 days of hCG treatment and the relative number of EDS-resistant Leydig cells. The Leydig cells that survived EDS administration showed characteristics which also occur in developing Leydig cells in the immature testis. It is concluded that, in rats pretreated with hCG for 2 days before EDS administration, new Leydig cells with some immature characteristics are formed. One of these characteristics is that these cells are insensitive to EDS. Journal of Endocrinology (1992) 134, 85–90

1989 ◽  
Vol 123 (2) ◽  
pp. 197-203 ◽  
Author(s):  
G. Edwards ◽  
R. Lendon ◽  
I. D. Morris

ABSTRACT Ethane-1,2-dimethanesulphonate (EDS) destroys Leydig cells in the testis of the adult rat and subsequently a new population of Leydig cells develops. It has been reported that EDS is not cytocidal to the new immature Leydig cell population. In the present study, the effect of increasing the time-interval between injections of EDS on cytotoxicity to Leydig cells was examined. At time-intervals of 4–10 weeks between injections the response was similar to that seen after a single injection of EDS to the adult rat. Four days after the second injection, EDS was found to reduce substantially serum testosterone concentrations and in-vitro binding of 125I-labelled human chorionic gonadotrophin (hCG) to testicular LH receptors which can be correlated with Leydig cell destruction. However, when the interval was only 2 or 3 weeks there was no reduction in serum testosterone, and 125I-labelled hCG binding was not so markedly reduced. During days 1–6 after a second injection of EDS, administered 3 weeks after the first, there were marked reductions in serum testosterone concentrations and in 125I-labelled hCG binding to testis homogenates within 24 h. Recovery from the effects of EDS was rapid, and increased Leydig cell activity was seen from 2 to 6 days after injection. In contrast to the established changes in the adult rat, there was only a 50% reduction in the number of Leydig cells positive for 3β-hydroxysteroid dehydrogenase 2 days after the second injection of EDS, and after 6 days the number of cells had increased. These experiments show that the immature Leydig cell of the rat is sensitive to the cytotoxic effects of EDS but that the temporal changes in Leydig cell activity after EDS treatment are different in developing and mature Leydig cell populations. The data are consistent with the view that EDS is preferentially cytotoxic towards steroidogenically active Leydig cells, allowing the resident population of precursor cells to continue to respond to the prevailing homeostatic mechanisms. Journal of Endocrinology (1989) 123, 197–203


1987 ◽  
Vol 114 (3) ◽  
pp. 459-467 ◽  
Author(s):  
V. Papadopoulos ◽  
P. Kamtchouing ◽  
M. A. Drosdowsky ◽  
M. T. Hochereau de Reviers ◽  
S. Carreau

ABSTRACT Production of testosterone and oestradiol-17β by Leydig cells from adult rats was stimulated by LH or dibutyryl cyclic AMP (10 and 2·5-fold respectively). The addition of spent medium from normal, hemicastrated or γ-irradiated rat seminiferous tubule cultures, as well as from Sertoli cell cultures, to purified Leydig cells further enhanced both basal (44 and 53% for testosterone and oestradiol-17β respectively) and LH-stimulated (56 and 18%) steroid output. Simultaneously, a decrease (20–30%) in intracellular cyclic AMP levels was observed. This stimulating factor (or factors) secreted by the Sertoli cells is different from LHRH, is of proteinic nature and has a molecular weight ranging between 10 000 and 50 000; its synthesis is not controlled by FSH nor by testosterone. This factor(s) involved in rat Leydig cell steroidogenesis, at a step beyond the adenylate cyclase, does not require protein synthesis for testosterone formation whereas it does for oestradiol-17β production. It should be noted that a germ cell–Sertoli cell interaction modulates the synthesis of this factor(s). J. Endocr. (1987) 114, 459–467


1987 ◽  
Vol 112 (2) ◽  
pp. 311-NP ◽  
Author(s):  
H. D. Nicholson ◽  
R. T. S. Worley ◽  
S. E. F. Guldenaar ◽  
B. T. Pickering

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


1994 ◽  
Vol 143 (3) ◽  
pp. 549-556 ◽  
Author(s):  
N R Jana ◽  
S Bhattacharya

Abstract Leydig cells isolated from goat testis were sonicated and pure nuclear preparations obtained for 125I-3,5,3′-triiodothyronine (T3)-binding assay. Under optimum assay conditions of pH 7·2 at 37 °C and 90 min of incubation, binding of 125I-T3 to Leydig cell nuclei reached saturation at 1·2 nmol/l concentration. A Scatchard analysis of T3 binding exhibited a Kd of 0·535 × 10−9 mol/l and a maximum binding capacity of 1·25 pmol/mg DNA. Competitive inhibition studies showed T3 binding to be analogue specific. The physiological relevance of T3 binding to goat Leydig cell was examined by adding increasing concentrations of T3 to the Leydig cell incubation (1×10 cells/incubation). T3 (10, 25 and 50 ng/ml or 4, 10 and 20 ng/incubation) resulted a dose dependent increase in androgen release and in all cases stimulation of androgen release was statistically significant (P<0·01) compared with control. Stimulation of Leydig cell androgen release by T3 was significantly inhibited by actinomycin-D (P<0·01) and cycloheximide (P<0·01). T3 had additive stimulatory effects on LH-augmented androgen release from Leydig cells. T3 (50 ng/ml or 20 ng/incubation) effected a more than twofold increase in Leydig cell protein synthesis compared with control and both actinomycin-D and cycloheximide (50 μg/ml) inhibited it completely. The data indicated that the stimulatory effect of T3 on androgen release is mediated via T3-induced protein(s). Sub-cellular fractions obtained from T3-treated Leydig cells showed an increase in protein synthesis in mitochondrial and soluble supernatant fractions (100 k sup) and it was only 100 k sup which stimulated androgen release from Leydig cells in separate incubations. Treatment of 100 k sup with trypsin or heat abolished its stimulatory effect. Incubation of Leydig cells with T3 for different times showed an increase in protein synthesis prior to the stimulation of androgen release. The results therefore indicated that T3 binding to Leydig cells induced the generation of a proteinaceous factor(s) which in turn stimulated androgen release. Journal of Endocrinology (1994) 143, 549–556


1985 ◽  
Vol 105 (3) ◽  
pp. 311-NP ◽  
Author(s):  
I. D. Morris

ABSTRACT Weekly doses of the Leydig cell cytotoxic ethylene dimethanesulphonate (EDS) were administered to adult male rats in an attempt to study the endocrine activity of the testis in the absence of Leydig cells. One week after the first dose serum testosterone and LH concentrations and seminal vesicle weights were close to levels in castrated rats and testicular human chorionic gonadotrophin (hCG) binding was severely depressed. These changes were maintained for a further week but subsequently began to return to, but did not achieve, control levels. After six weekly doses seminal vesicle weight and serum testosterone concentrations were significantly higher than in the castrated rats. Serum LH concentrations were declining towards control values at 4 weeks but had risen again at 6 weeks. Serum FSH concentrations were raised to about 50% of the value in castrated rats throughout the period studied. Testis weight and hCG binding, which initially fell, were partially restored at 6 weeks and spermatogenesis was recovering. The data show that responses of the testis to multiple doses of EDS are similar to those after a single dose. This apparent resistance indicates that the regenerating Leydig cells are functionally different from the mature Leydig cell. The similarities between the maturing Leydig cell seen after EDS destruction and those in the immature rat suggest that EDS will provide a valuable model for the investigation of Leydig cell physiology. J. Endocr. (1985) 105, 311–316


1991 ◽  
Vol 130 (1) ◽  
pp. 107-114 ◽  
Author(s):  
A. J. Tilbrook ◽  
D. M. de Kretser ◽  
I. J. Clarke

ABSTRACT To determine whether Leydig cells produce inhibin in the ram, Leydig cells were stimulated by administering human chorionic gonadotrophin (hCG) or raising the levels of endogenous LH by an injection of gonadotrophin releasing hormone (GnRH). Plasma concentrations of testosterone increased in the 72 h after either a single injection (P < 0·05) or two injections (P < 0·01) of hCG. Plasma concentrations of inhibin were not significantly influenced by either one or two injections of hCG. Administration of GnRH (1 μg) caused an 11-fold increase in plasma concentrations of LH but did not influence concentrations of inhibin in either the jugular or testicular veins (pampiniform plexus). In contrast, concentrations of testosterone were increased by about fourfold in both jugular (P < 0·01) and testicular (P < 0·05) veins. The concentrations of inhibin in the testicular vein were 1·3-fold higher than in the peripheral plasma (P < 0·05) both before and following treatment with GnRH whereas the concentrations of testosterone were 18- to 21-fold greater than in peripheral concentrations. In view of the difference in concentrations of inhibin between testicular and jugular veins, in a further experiment a sample was taken from the jugular vein, a vein located in the tunica vasculosa of the testis (testicular vein) and from a vein (spermatic vein) and lymph vessels located in the spermatic cord. The mean (± s.e.m.) concentrations of inhibin were highest in the testicular lymph (45·93±4·21 μg/l; P < 0·001) compared with the peripheral (4·14±0·31 μg/l), spermatic (8·0±1·17 μg/l) or testicular (6·4±0·82 μg/l) plasma. Plasma concentrations of inhibin were significantly higher in the spermatic vein than in the testicular vein (P < 0·05) and jugular vein (P < 0·01), and concentrations of inhibin in the testicular vein were significantly (P < 0·05) higher than in the jugular vein. There were no significant differences in the concentrations of testosterone in the spermatic vein, testicular vein or testicular lymph but the concentrations of testosterone in the peripheral plasma were significantly (P < 0·05) less than in the testicular plasma or lymph. These results suggest that, in the ram, the Leydig cell does not respond to hCG or endogenous LH by secreting inhibin or by influencing other cells within the testis to secrete inhibin within the time-frame of these experiments. The low testicular to jugular differences in the concentration of inhibin and the high concentrations of inhibin in the testicular lymph suggest that the lymph may be an important route of secretion of inhibin from the testis in the ram. Journal of Endocrinology (1991) 130, 107–114


1988 ◽  
Vol 119 (3) ◽  
pp. 475-NP ◽  
Author(s):  
G. Edwards ◽  
R. G. Lendon ◽  
I. D. Morris

ABSTRACT A single injection of ethane-1,2-dimethanesulphonate (EDS; 100 mg/kg) selectively destroys Leydig cells in the testis of the adult rat; however, unconfirmed reports indicate that Leydig cells in the immature rat are not affected. In this study the effect of EDS was examined 2 days after treatment of rats aged 20, 25 or 35 days. There was a large reduction in the in-vitro binding of 125I-labelled human chorionic gonadotrophin (hCG) to the homogenates of testes from EDS-treated immature rats. EDS reduced the testosterone content of the testes at all ages studied, but 2 days after injection had only significantly lowered the serum testosterone concentration of 25- or 35-day-old animals. Light microscopic examination of the testis of the 22-day-old rat, 2 days after treatment with EDS, indicated that there were still many cells staining for 3β-hydroxysteroid dehydrogenase. The interstitium also contained numerous atypical cells which did not stain for 3β-hydroxysteroid dehydrogenase. Electron microscopy of testes from the 22-day-old EDS-treated rat showed that Leydig cells were still present in the interstitium together with macrophages and fibroblast-like cells. Six days after EDS treatment of 20-day-old rats, but not 35-day-old rats, there was an increase in the binding of 125I-labelled hCG to testis homogenate to 70% of control value. Testicular testosterone content 6 days after treatment of the 20-day-old rat had risen to 50% of the control testis value. These changes documented in the 20-day-old rat after EDS treatment can be explained by either a cytocidal effect with subsequent repopulation of new Leydig cells which has been described in the adult rat or by a reversible cytotoxic action which has not previously been documented. J. Endocr. (1988) 119, 475–482


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