Impaired testosterone biosynthesis in cryptorchidism

Altered expression of CYP17A1 and CYP19A1 in undescended testes of dogs with unilateral cryptorchidism

Cryptorchidism is the most common disorder of sex development in dogs and testosterone plays a crucial role in the inguinal phase of the testes descending into the scrotum. The molecular background of impaired testosterone synthesis in the testes of cryptorchid dogs is poorly elucidated. In this study, we analyzed the expression of four genes involved in testicular steroidogenesis (CYP17A1, CYP19A1, HSD3B2 and HSD17B3) in undescended and contralateral scrotal testes from inguinal unilateral cryptorchid dogs (n = 13) and from the scrotal gonads of normal males (n = 15). We found that transcript level of CYP17A1 was significantly increased in inguinal gonads, while the level of CYP19A1 was decreased. For these two genes, we analyzed the methylation level of single CpG sites in the promoter region localized within putative target sites for testicular transcription factors (NUR77, CREB, CAR and HSF2). A correlation between decreased methylation in the promoter of CYP17A1 and its increased transcript level in undescended gonads was observed, but the change in protein level was not significant. We also resequenced the 5'-flanking region of both genes and two known polymorphic sites, SNP in CYP17A1 and an indel in CYP19A1, were found. However, the distribution of the variants in affected (n = 80) and control (n = 75) dogs was not associated with cryptorchidism. We tentatively conclude that the altered expression of CYP17A1 and CYP19A1 in undescended testes could be caused by their exposure to increased temperature in the body. Furthermore, we showed that the identified polymorphisms cannot be considered markers associated with a predisposition to cryptorchidism.

Differential gene expression in the testes of different murine strains under normal and hyperthermic conditions

Cryptorchidism and scrotal heating result in abnormal spermatogenesis, but the mechanism(s) prescribing this temperature sensitivity are unknown. It was previously reported that the AKR/N or MRL/MpJ-+/+ mouse testis is more heat-resistant than the testis from the C57BL/6 strain. We have attempted to probe into the mechanism(s) involved in heat sensitivity by examining global gene expression profiles of normal and heat-treated testes from C57BL/6, AKR/N, and MRL/MpJ-+/+ mice by microarray analysis. In the normal C57BL/6 testis, 415 and 416 transcripts were differentially expressed (at least 2-fold higher or lower) when compared with the normal AKR/N and MRL/MpJ-+/+ testis, respectively. The AKR/N and MRL/MpJ-+/+ strains revealed 268 differentially expressed transcripts between them. There were 231 transcripts differentially expressed between C57BL/6 and 2 purported heat-resistant strains, AKR/N and MRL/MpJ-+/+. Next, the testes of C57BL/6 and AKR/N mice were exposed to 43 degrees C for 15 minutes and harvested at different time points for terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) studies and microarrays. An increase of TUNEL-positive germ cell numbers was significant 8 hours after heat exposure in the C57BL/6 mouse. However, this increase was not observed in the AKR/N mouse until 10 hours after heat exposure. All tubules showed germ cell loss and disruption in C57BL/6 testis 24 hours after heat shock. In contrast, although a number of seminiferous tubules showed an abnormal morphology 24 hours post-heat shock in the AKR/N mouse, many tubules still retained a normal structure. Numerous transcripts exhibited differential regulation between the 2 strains within 24 hours after heat exposure. The differentially expressed transcripts in the testes 8 hours after heat exposure were targeted to identify the genes involved in the initial response rather than those attributable to germ cell loss. Twenty transcripts were significantly down-regulated and 19 genes were up-regulated by hyperthermia in C57BL/6 and did not show a parallel change in the AKR/N testis. Conversely, heat shock resulted in 30 up-regulated transcripts and 31 down-regulated transcripts in AKR/N that were not similarly regulated in C57BL/6. A number of genes shared similar differential expression patterns and differential regulation by hyperthermia in both strains of mice. Taken together, the results of the present study indicate that the diverse genetic backgrounds in the 3 strains lead to major differences in normal testis gene expression profiles, whereas the differences in heat shock responses involve a significantly smaller number of genes. The data generated may provide insights regarding gene networks and pathways involved in heat stress and their relationship to spermatogenesis.

Effect of experimental infection with Trypanosoma congolense and scrotal insulation on Leydig cell steroidogenesis in the ram

Testicular steroid content and Leydig cell steroidogenesis in vitro were investigated in rams on Days 28 and 58 after Trypanosoma congolense infection and were compared with those of rams in which testicular temperature had been raised artificially by insulation of the scrotum for 58 d. Testicular testosterone content increased significantly on Day 28 after infection but was lower than that of controls on Day 58 while it increased in scrotal-insulated rams compared with that of controls by Day 58. Testicular progesterone was undetectable in the control and trypanosome-infected groups throughout the experiment, but it increased in the insulated rams by day 58. Basal (unstimulated) Leydig cell testosterone production in the infected rams was similar to that of control rams on Day 28 but was significantly lower on Day 58. Stimulation of Leydig cell testosterone production with hCG or 22R-hydroxycholesterol (22ROHC) significantly reduced in infected rams at both 28 and 58 d after infection as well as in scrotal-insulated rams on Day 58. It is concluded that the increase in testicular testosterone content in the infected and scrotal-insulated rams on Days 28 and 58, respectively, was induced by elevation of testicular temperature by trypanosome infection, perhaps through an effect on testicular blood flow. Reduced testosterone production by Leydig cells from infected and scrotal-insulated rams in response to hCG and 22ROHC suggests that trypanosome-induced pyrexia might be involved in reducing Leydig cell steroidogenesis and subsequent plasma testosterone levels, possibly by affecting enzymes involved in steroid biosynthesis.

Apoptosis and cell removal in the cryptorchid rat testis

In order to determine that apoptosis is responsible for large-scale germ cell elimination, we analyzed cells from cryptorchid testes both in histological sections and among those isolated in vitro. Apoptotic testicular cells during 3 to 7 days were only 8 to 30%, reaching a maximum of 80% by the end of 15 days of cryptorchidism. A similar trend was also observed with the number of dead cells. The process of large-scale germ cell removal in the initial stages was facilitated by the formation of multinucleated giant cells, which stained negative for apoptosis. Increase in oxidative stress and decrease in intratesticular testosterone was also observed. The above findings indicate that large-scale germ cell removal, at least during initial stages of cryptorchidism is not solely as a result of apoptosis. Declined intra testicular testosterone, elevated temperature and high oxidative stress following cryptorchidism probably affect cell viability and trigger a fast pace cell removal through giant cell formation.

Unilateral cryptorchidism corrected in prepubertal age: evaluation of sperm parameters, hormones, and antisperm antibodies in adult age

OBJECTIVE

To evaluate whether prepubertal orchidopexy for unilateral cryptorchidism can reduce adult dysspermia.

DESIGN

Patient follow-up comparison with control groups.

SETTING

Surgical and endocrinologic sections of a children's hospital and a university infertility-care center.

PATIENT(S)

Seventy-one patients with unilateral cryptorchidism who underwent orchidopexy in prepubertal age (6.4 +/- 2.8 years) were followed up as adults (20.0 +/- 2.8 years).

MAIN OUTCOME MEASURE(S)

Patients underwent testicular examination and hormonal evaluation, 49 of these had semen analysis and antisperm antibody tests. Semen results were compared with those of two age-matched control groups: a group of 20 healthy, randomly selected subjects and a group of 20 patients operated on in postpubertal age for cryptorchidism.

RESULT(S)

Unilateral reduced testis size was found in 30.1% of patients, eight patients had a low LH level, eight had a low T level, and none had abnormal FSH values. Antisperm antibodies were found in 1 of 49 cases. Cluster analysis of sperm parameters showed that the mean values of patients were worse than those of the healthy controls but better than those of the subjects operated on in postpubertal age.

CONCLUSION(S)

This study indicates that prepubertal orchidopexy can given better results than postpubertal correction.

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

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 degrees 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 degrees 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.

Environmental temperature and cryptorchidism: effects on pregnenolone-sulfatase of mice testicular tissue

This study examined the capacity of abdominal organs, such as the scrotal testis, exposed to environmental temperature to hydrolyze pregnenolone sulfate. The cryptorchid state of exposure to 34 degrees C during 14 days decreased testis weight by 38 and 23%. But the enzymatic activity (nanomoles of free steroid/testis) was significantly higher (p < .05) compared with the control. Moreover, a rise in the environmental temperature combined with cryptorchidism in mice, two conditions that induced testicular damage, has been related to the elaboration of factors capable of modifying, through paracrine mechanism, the androgen biosynthesis. The presence of this factor could lead to an increase in the hydrolysis of pregnenolone sulfate, but as for cryptorchidism or high environmental temperature exposure, when cryptorchid mice were exposed to temperatures of 34 degrees C an apparent synergism of both conditions produced a decrease of 66% in testis weight. It would appear that the steroid sulfatase is predominantly located in the interstitial epithelium. This study suggests that cryptorchidism and hyperthermia damage the tubular epithelium by different mechanisms.

Ratios of serum concentrations of testosterone and progesterone from yearling bulls with small testes

Thirty crossbred bulls, 12 to 13 mo of age, were used to examine the relationship of testosterone and progesterone concentrations and testosterone: progesterone ratio to measurements of testicular function. Bulls were allotted to 1 of 2 groups based on scrotal circumferences (SC) as follows: the Small SC (n=20) group had scrotal circumference less than 28 cm while the Large SC (n=10) group had scrotal circumference greater than 28 cm. All bulls were administered GnRH (100 mug, im), and blood was obtained immediately prior to injection (t=0), 30 min after injection (t=30) and 2 to 3 h after injection (t=150). Serum was assayed for concentrations of testosterone and progesterone. Semen was evaluated for the percentage of morphologically normal spermatozoa. Testicular parenchyma was sectioned and stained, and 300 cross sections per testis of seminiferous tubules were examined under a light microscope and classified as either active (spermatocytes and spermatids present) or inactive (no spermatocytes or spermatids present). Although progesterone concentrations varied widely (range: 21 pg/ml to 1070 pg/ml), repeated measurements from individual bulls were highly correlated (r(2)=0.74) and did not change significantly (P > 0.1) in response to GnRH treatment. Small SC bulls had a higher percentage of inactive seminiferous tubules (P < 0.001) and a lower percentage morphologically normal spermatozoa (P < 0.001) than Large SC bulls, but no differences in testosterone or progesterone concentrations or in the ratio of testosterone: progesterone were detected. Mean serum testosterone concentration increased (P < 0.0001) by 30 min after GnRH treatment and continued to increase (P < 0.0001) through t=150 but did not differ (p > 0.1) between groups. Normal testosterone secretion in response to GnRH injection suggested that no biochemical lesions in the testosterone production pathway were present in bulls with very small scrotal circumference.

Congenital abnormalities of the genitalia of cattle, sheep, goats, and pigs

The essential steps in embryology of the genitalia and its sexual differentiation, are briefly reviewed. The major intersex states in domestic ruminants and pigs are briefly considered. Major attention is directed to anomalies of the reproductive organs of mature female and male animals that are likely to compromise fertility. Emphasis is placed on clinical and pathologic findings and on occurrence and pathogenesis of recorded defects.

Effect of cryptorchidism on testicular and Leydig cell androgen production in the mouse

Unilateral cryptorchidism was induced surgically in adult mice and the effects on testicular and Leydig cell steroidogenesis were studied after 7 weeks. There was a 60% reduction in weight of the cryptorchid testis and this was associated with a significant reduction in intratesticular androgen content, both under basal conditions and following an injection of hCG. Testicular androgen production in vitro was also significantly lower in the cryptorchid testis compared to the scrotal testis, again under both basal conditions (29 +/- 6% of control) and in the presence of hCG (46 +/- 9% of control). Scrotal testes from the unilaterally cryptorchid animals did not show any significant difference in steroidogenic capacity compared to testes from untreated control animals. The decrease in steroidogenic capacity of the cryptorchid testis was due, at least in part, to a reduction in activity for each Leydig cell. In four experiments, androgen production by Leydig cells isolated from cryptorchid testes was 48 +/- 9% of cells from scrotal testes in the presence of a saturating dose of hCG. Under basal conditions the effect was more variable between experiments with steroid secretion by Leydig cells from cryptorchid testes being 58 +/- 32% of that for cells from scrotal testes. Leydig cell steroidogenesis in the scrotal testes of unilaterally cryptorchid animals did not differ significantly from untreated controls. These results show that induced cryptorchidism in the mouse causes a significant reduction in Leydig cell activity. This is apparently different from the effects of this procedure on the rat and raises the possibility that intratesticular regulation differs between the two species.

Testicular steroid sulfatase in a cryptorchid rat strain

Steroid sulfatase (STS) activity was studied in scrotal and abdominal testes from genetically unilateral cryptorchid rats. Specific STS activity was significantly increased in microsomes from abdominal and scrotal testes of the cryptorchid animals as compared to that of control ones. When expressed per gonad, STS activity was only enhanced in the scrotal testis. No difference in the enzyme affinity was observed between descended and undescended testes. Testosterone content was markedly reduced in the abdominal testes. Normal plasma testosterone levels together with elevated LH levels were measured in the cryptorchid rats. The existence of differences in STS expression between descended and undescended testes gives additional support for this enzymatic activity being implicated in testicular function.

Testosterone, androstenedione, progesterone and 17 alpha-hydroxyprogesterone in plasma and testes of immature rats under basal conditions and after hCG stimulation. Effect of bilateral cryptorchidism

Rats were made bilaterally cryptorchid at 21 days of age; sham-operated rats were used as controls. At 35 days, the animals were injected i.m. with saline or with 10 IU hCG. Progesterone, 17-hydroxyprogesterone, androstenedione and testosterone were measured in both testes and plasma under basal conditions and 2, 4, 8, 12, 24 and 72 h respectively after injection. The plasma levels and intratesticular contents of the steroids were generally lower in cryptorchid rats. The patterns of the steroid response to hCG were similar in both groups: in the testes and in the plasma, they increased acutely following hCG injection (except testicular androstenedione), then, after 72 h, returned to normal values in the plasma but remained higher than the basal values in the testes. These results suggest that there are no gross abnormalities in the testicular steroidogenic pathways and that the mechanism of action of hCG on the Leydig cells is unaltered in bilaterally cryptorchid immature rats.

Testicular-epididymal fusion abnormality in undescended testis

In the course of 1195 operations, performed in children with cryptorchidism, the testes were studied for size, turgor and fusion with the epididymis. Inquiries were made into the reasons of fusion disorders which were conspicuously numerous. Attention is called to this not too familiar condition which seems to play an important role in the emergence of fertility disorders in men with congenital cryptorchidism.