Human serum LH inhibitor(s): behaviour and contribution to in vitro bioassay of LH using dispersed mouse Leydig cells

1989 ◽  
Vol 121 (1) ◽  
pp. 46-54 ◽  
Author(s):  
Ying-Qing Ding ◽  
Ilpo Huhtaniemi
Keyword(s):  
Human Serum ◽  
Leydig Cell ◽  
Binding Studies ◽  
In Vitro Bioassay ◽  
Lh Receptor ◽  
Testosterone Production ◽  
Free Serum ◽  
Source Of Error ◽  
Mouse Leydig Cell

Abstract. The present study aimed at investigating the nature and causes of non-parallelism in testosterone responses to serial dilutions of peripheral serum and standard LH preparations in the mouse Leydig cell in vitro bioassay of LH. Immunoadsorption with monoclonal antibody to the β-subunit of LH was used to obtain LH-free serum; the procedure removed more than 98% of the immunoassayable LH. When a constant amount of the LH-free serum was added to standard dilutions, the bioassay dose-response curves to serum dilutions and standards became parallel, i.e. the well-known source of error of this assay system was eliminated. When standard curves prepared in medium and LH-free serum (final concentration 10%) were compared, no effect of the serum was found on basal cAMP and testosterone production. However, the LH-stimulated testosterone and cAMP production were suppressed by serum by a rather constant factor of 40%. Mild heating (60°C, 15 min) or treatment with dextran-coated charcoal, but not ether extraction, was able to eliminate the inhibitory activity of the LH-free serum. Binding studies demonstrated that [125I]hCG interaction with mouse Leydig cell homogenates was inhibited by LH-free serum in a fashion indicative of reduced LH receptor number, but not of reduced binding affinity. In conclusion, these data show that human serum contains LH inhibitor(s) which affect the LH-receptor interaction and LH stimulated testosterone production in mouse Leydig cell in vitro. The effect is marked in serum concentration over 1.5% and it shows only minor variation between individual sera. This source of error can be effectively removed from the LH in vitro bioassay by using LH-free serum for preparation of dilutions of LH standards.

AN IMPROVED IN VITRO BIOASSAY METHOD FOR MEASURING LUTEINIZING HORMONE (LH) ACTIVITY USING MOUSE LEYDIG CELL PREPARATIONS

1974 ◽  
Vol 77 (4) ◽  
pp. 655-671 ◽  
Author(s):  
M.-P. Van Damme ◽  
D. M. Robertson ◽  
E. Diczfalusy
Keyword(s):  
Luteinizing Hormone ◽  
Leydig Cell ◽  
Marked Reduction ◽  
Improved Method ◽  
In Vitro Bioassay ◽  
Bioassay Method ◽  
Adult Mice ◽  
Assay Design ◽  
Mouse Leydig Cell

ABSTRACT An improved in vitro bioassay method for the measurement of LH activity is presented. The method is based on the assay of testosterone produced by "Leydig cell" preparations from mouse testes in the presence of added gonadotrophin. The method is significantly improved in terms of sensitivity, precision and practicability when compared to the previously described bioassay method employing decapsulated testes from adult mice. The sensitivity of the improved method is 15 μIU for HCG and 50 μIU for HMG. The useful range of the method is 15–260 μIU for HCG and 50–900 μIU for HMG. Using a 3 + 3 point assay design with each dose in quadruplicate, a mean index of precision (λ̅) of 0.044 was obtained in 19 assays. Human FSH, TSH, ACTH, LTH, STH, oxytocin, vasopressin and LHRH preparations did not influence the bioassay method at levels likely to be found in biological samples. A good correlation was found between estimates obtained by the "Leydig cell" method and by the method using decapsulated testes when various HCG and HMG preparations were used. With the proposed method at least 30 samples can be assayed each week by 2 persons, with a marked reduction in cost.

Changes in the bioactivity to immunoreactivity ratio of circulating luteinizing hormone in impotent men treated with testosterone undecanoate

1989 ◽  
Vol 120 (3) ◽  
pp. 284-288 ◽  
Author(s):  
C. Carani ◽  
M. F. Celani ◽  
D. Zini ◽  
A. Baldini ◽  
L. Della Casa ◽  
...  
Keyword(s):  
Leydig Cell ◽  
Serum Levels ◽  
Mean Value ◽  
Serum Concentrations ◽  
Placebo Administration ◽  
In Vitro Bioassay ◽  
Testosterone Undecanoate ◽  
The Mean ◽  
Mouse Leydig Cell

Abstract. Testosterone undecanoate was administered orally (80 mg twice daily) for 30 days to 10 impotent men with mild Leydig cell failure, age 28 to 42 years. Placebo was administered for 30 days both before and at the end of testosterone undecanoate therapy. Serum levels of bioactive LH, immunoreactive LH and testosterone were determined in basal conditions (day zero), 30 days after the first placebo administration, at the 15th and 30th day of testosterone undecanoate therapy, and at the end of the second treatment with placebo (90th day). Bioactive LH was measured by a sensitive and specific in vitro bioassay based on testosterone production by mechanically dispersed mouse Leydig cell preparations. Immunoreactive LH and testosterone were determined by a doubleantibody RIA technique. The results were compared with those obtained in 30 untreated normal young men. In the basal state, serum concentrations of immunoreactive LH were significantly higher in the patients (P< 0.02) than in control subjects, whereas testosterone levels were significantly lower (P< 0.001) in the impotent men. In contrast, bioactive LH levels and the bioactive LH to immunoreactive LH ratios were similar in the two groups. In the patients, at the 15th day of treatment with testosterone undecanoate, serum levels of testosterone and bioactive LH were significantly higher (P< 0.01) than basal values, whereas immunoreactive LH concentrations showed no significant changes. Consequently, the bioactive LH to immunoreactive LH ratios rose significantly (P< 0.01). At the 30th day of treatment with testosterone undecanoate, the mean value of bioactive LH and the mean bioactive LH to immunoreactive LH ratio were significantly higher (P< 0.01) in the patients than in control men, whereas the mean levels of testosterone and immunoreactive LH were similar in the two groups. Neither the first nor the second treatment with placebo changed the hormone values observed in basal conditions. The results support the experimental evidence that androgens may increase the bioactivity of circulating LH.

Estrogen induces secretary proteins in transformed mouse Leydig cell in vivo, but not in vitro

1984 ◽  
Vol 124 (1) ◽  
pp. 277-282 ◽  
Author(s):  
Bunzo Sato ◽  
Yasuko Nishizawa ◽  
Makoto Nakao ◽  
Keizo Noma ◽  
Susumu Kishimoto ◽  
...  
Keyword(s):  
Leydig Cell ◽  
Mouse Leydig Cell

scholarly journals Mumps Virus Decreases Testosterone Production and Gamma Interferon-Induced Protein 10 Secretion by Human Leydig Cells

2003 ◽  
Vol 77 (5) ◽  
pp. 3297-3300 ◽  
Author(s):  
Ronan Le Goffic ◽  
Thomas Mouchel ◽  
Annick Ruffault ◽  
Jean-Jacques Patard ◽  
Bernard Jégou ◽  
...  
Keyword(s):  
Cell Cultures ◽  
Leydig Cell ◽  
Leydig Cells ◽  
Mumps Virus ◽  
Gamma Interferon ◽  
Testosterone Secretion ◽  
Testosterone Production

ABSTRACT Mumps virus is responsible for sterility. Here, we show that the mumps virus infects Leydig cells in vitro and totally inhibits testosterone secretion and that ribavirin in mumps virus-infected Leydig cell cultures completely restores testosterone production. Moreover, we show that gamma interferon-induced protein 10 (IP-10) is highly expressed by mumps virus-infected Leydig cells and that ribavirin does not block IP-10 production.

Increase in Leydig cell responsiveness in the unilaterally cryptorchid rat testis and its relationship to the intratesticular levels of testosterone

1984 ◽  
Vol 102 (3) ◽  
pp. 319-327 ◽  
Author(s):  
R. M. Sharpe ◽  
I. Cooper ◽  
D. G. Doogan
Keyword(s):  
Leydig Cell ◽  
Leydig Cells ◽  
Venous Blood ◽  
Cell Interaction ◽  
Adult Rats ◽  
Similar Reduction ◽  
Testosterone Production ◽  
Lh Releasing Hormone ◽  
Unilateral Cryptorchidism

ABSTRACT Adult rats were made unilaterally cryptorchid (UCD) and 6–7 weeks later Leydig cells were isolated from the scrotal and abdominal testes and their capacity to secrete testosterone in vitro was compared. Basal testosterone production by Leydig cells from the abdominal testes of UCD rats was lowered, compared with cells from the contralateral scrotal testes, whilst their responsiveness to both human chorionic gonadotrophin and an LH releasing hormone agonist was enhanced two- to threefold (P< 0·001) compared both with cells from the contralateral scrotal testes and with cells isolated from untreated rats of the same age. In the UCD rats, concentrations of testosterone in testicular interstitial fluid (IF) were reduced (P< 0·001) by 70–90% in abdominal, compared with scrotal, testes. A similar reduction was evident in the levels of testosterone in spermatic venous blood, and both this decrease and that in IF levels of testosterone varied according to the degree of testicular involution. The ontogeny of the above changes was investigated. After induction of unilateral cryptorchidism, the weight of the abdominal compared with the scrotal testis declined slowly, such that by day 5 there was only a 25% reduction in weight compared with a 70% reduction by day 40. In contrast, the levels of testosterone in IF from abdominal testes declined rapidly, such that by day 5 an 80% reduction was attained, compared with scrotal testes, with little further change by day 40. Hormone-stimulated testosterone production by Leydig cells isolated from the abdominal testes was unchanged or marginally reduced over the first 3 days compared with cells from the scrotal testes, but by day 5 there was a significant increase in responsiveness; this increase was of smaller magnitude than that evident at day 40. These results suggest a possible association between the fall in intratesticular levels of testosterone induced by unilateral cryptorchidism and the Leydig cell hypertrophy and hyper-responsiveness that occurs in the same testes. The implications with respect to altered Sertoli–Leydig cell interaction are discussed. J. Endocr. (1984) 102, 319–327

scholarly journals Androgen profiles during pubertal Leydig cell development in mice

Reproduction ◽  
2010 ◽  
Vol 140 (1) ◽  
pp. 113-121 ◽  
Author(s):  
Xiufeng Wu ◽  
Ramamani Arumugam ◽  
Ningning Zhang ◽  
Mary M Lee
Keyword(s):  
Leydig Cell ◽  
Developmental Changes ◽  
Side Chain ◽  
Adult Rat ◽  
Testosterone Production ◽  
Chain Cleavage ◽  
Cleavage Enzyme ◽  
Species Specific

Postnatal Leydig cell (LC) development in mice has been assumed empirically to resemble that of rats, which have characteristic hormonal profiles at well-defined maturational stages. To characterize the changes in LC function and gene expression in mice, we examined reproductive hormone expression from birth to 180 days, and quantified in vivo and in vitro production of androgens during sexual maturation. Although the overall plasma androgen and LH profiles from birth through puberty were comparable to that of rats, the timing of developmental changes in androgen production and steroidogenic capacity of isolated LCs differed. In mice, onset of androgen biosynthetic capacity, distinguished by an acute rise in androstenedione and testosterone production and an increased expression of the steroidogenic enzymes, cytochrome P450 cholesterol side-chain cleavage enzyme and 17α-hydroxylase, occurred at day 24 (d24) rather than at d21 as reported in rats. Moreover, in contrast to persistently high testosterone production by pubertal and adult rat LCs, testosterone production was maximal at d45 in mice, and then declined in mature LCs. The murine LCs also respond more robustly to LH stimulation, with a greater increment in LH-stimulated testosterone production. Collectively, these data suggest that the mouse LC lineage has a delayed onset, and that it has an accelerated pace of maturation compared with the rat LC lineage. Across comparable maturational stages, LCs exhibit species-specific developmental changes in enzyme expression and capacity for androgen production. Our results demonstrate distinct differences in LC differentiation between mice and rats, and provide informative data for assessing reproductive phenotypes of recombinant mouse models.

Effects of clodronate-containing liposomes on testicular macrophages and Leydig cells in vitro

1997 ◽  
Vol 155 (1) ◽  
pp. 87-92 ◽  
Author(s):  
DE Brigham ◽  
G Little ◽  
YO Lukyanenko ◽  
JC Hutson
Keyword(s):  
Direct Effect ◽  
Dose Response ◽  
Leydig Cell ◽  
Leydig Cells ◽  
Direct Effects ◽  
Testosterone Production ◽  
Identical Response ◽  
Testicular Macrophages

We undertook the present studies to determine if clodronate-containing liposomes have direct effects on Leydig cells. Macrophages and Leydig cells were isolated and maintained separately in culture. Following treatment with clodronate-containing liposomes, macrophages were killed in a dose-response fashion over a range of 5-200 microliters liposomes. By comparison, a 500 microliters dose was required to kill Leydig cells, but this was not dependent upon clodronate since liposomes containing buffer elicited an identical response. The concentration of testosterone in medium from Leydig cells treated with clodronate-containing liposomes was significantly reduced compared with untreated cells. However, we subsequently found that liposomes can adsorb testosterone. Therefore, testosterone production was determined at various times following removal of liposomes from Leydig cells, thereby circumventing this complication. It was found that testosterone production was not altered by liposomes under these conditions. Finally, free clodronate had no effect on testosterone production, even at doses representing the amount present within the 500 microliters dose of liposomes. In summary, clodronate-containing liposomes killed testicular macrophages at a far smaller dose than required to kill Leydig cells. Most importantly, neither liposomes no free clodronate had a direct effect on testosterone production. Thus, clodronate-containing liposomes represent a valuable tool to study Leydig cell-macrophage interactions.

scholarly journals Corticotropin-Releasing Factor (CRF) Agonists Stimulate Testosterone Production in Mouse Leydig Cells through CRF Receptor-1*

Endocrinology ◽  
1998 ◽  
Vol 139 (2) ◽  
pp. 651-658 ◽  
Author(s):  
Nadja Heinrich ◽  
Mike R. Meyer ◽  
Jens Furkert ◽  
Annette Sasse ◽  
Michael Beyermann ◽  
...  
Keyword(s):  
Leydig Cell ◽  
Leydig Cells ◽  
Pituitary Cells ◽  
Camp Production ◽  
Cos Cells ◽  
Testosterone Production ◽  
Primary Mouse ◽  
Rat Pituitary ◽  
Rat Pituitary Cells ◽  
Mouse Leydig Cell

Abstract The influence of CRF on testosterone production in primary mouse Leydig cell cultures was studied, and the type of CRF receptor (CRF-R) involved in this activity was determined. CRF directly stimulated testosterone production in mouse Leydig cells, but did not influence the maximum human (h)CG-induced testosterone production. The effect was time- and dose-dependent, saturable with an EC50 of 2.84 nm for hCRF, antagonized by the CRF antagonist α-helical CRF9–41, and accompanied by intracellular cAMP elevation. The rank order of potency of the natural CRF agonists, hCRF, ovine CRF, sauvagine, and urotensin, corresponded to that of their activities on CRF-R1 in rat pituitary cells and also to that reported for this receptor, but not for CRF-R2, when transfected into various cell lines. Furthermore, the difference in response of mouse Leydig cells to[ 11-d-Thr,12-d-Phe]- and[ 13-d-His,14-d-Leu]-ovine CRF corresponded to that measured when COS cells expressing CRF-R1 were activated, but was considerably smaller than that observed for activation of COS cells expressing CRF-R2α or -R2β. The messenger RNA encoding the mouse CRF-R1 was detected by RT-PCR in mouse Leydig cell preparations. In contrast to mouse Leydig cells, CRF agonists had no influence on the basal testosterone and cAMP production by rat Leydig cells, nor did the agonists or antagonist change the hCG-stimulated testosterone and cAMP production by these cells. It is concluded that mouse Leydig cells express CRF-R1, mediating elevation of testosterone production by CRF agonists through cAMP. Because potencies of CRF agonists in activating mouse Leydig cells were more than 10-fold lower compared with their potencies in stimulating rat pituitary cells, it is suggested that the coupling of the CRF-R1 to intracellular signaling in Leydig cells is different from that in corticotropic pituitary cells, at least in quantitative terms.

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