High expression of antizyme inhibitor 2, an activator of ornithine decarboxylase in steroidogenic cells of human gonads.

High activity of ornithine decarboxylase (ODC), the rate-limiting enzyme of polyamine synthesis, is typically present in rapidly proliferating normal and malignant cells. The mitotically inactive steroidogenic cells in rodent testis and ovaries, however, also display high ODC activity. The activity of ODC in these cells responds to luteinizing hormone, and inhibition of ODC reduces the production of steroid hormones. Polyamines and ODC also control proliferation of germ cells and spermiogenesis. The activity of ODC, especially in proliferating cells, is regulated by antizyme inhibitor (AZIN). This protein displaces ODC from a complex with its inhibitor, antizyme. We have previously identified and cloned a second AZIN, i.e. antizyme inhibitor 2 (AZIN2), which has the highest levels of expression in brain and in testis. In the present study, we have used immunohistochemistry and in situ hybridization to localize the expression of AZIN2 in human gonads. We found a robust expression of AZIN2 in steroidogenic cells: testicular Leydig cells and Leydig cell tumors, in ovarian luteinized cells lining corpus luteum cysts, and in hilus cells. The results suggest that AZIN2 is not primarily involved in regulating the proliferation of the germinal epithelium, indicating a different role for AZIN1 and AZIN2 in the regulation of ODC. The localization of AZIN2 implies possible involvement in the gonadal synthesis and/or release of steroid hormones.

Urethral stromal tumor with pacemaker cell phenotype.

Penile malignancies are rare in developed countries. The authors present a case of a penile urethral mesenchymal tumor occurring in a 51-year-old Caucasian male and displaying light microscopic, immunohistochemical, and ultrastructural features suggestive of a pacemaker cell type, combined with a lack of diagnostic features of any other established tumor category. The immunohistochemical profile was intensely positive for vimentin, PKC theta, and NSE and weakly positive to nonreactive for CD34 and smooth muscle actin, and entirely negative for CD117 (c-kit), S-100, and other markers. C-kit and PDGFRA gene analysis showed no mutations. Electron microscopy revealed tumor cells with plentiful cytoplasm and cytoplasmic processes/filopodia, both filled with intermediate filaments and occasional solitary focal densities. There were also prominent smooth endoplasmic reticulum cisternae, caveolae, neurosecretory granules, particularly concentrated in cytoplasmic processes, and synaptic-type structures. Poorly formed basal lamina, gap junctions, and intercellular collagen aggregates, consistent with skeinoid-type fibers, were also noted. Interstitial cells with potential pacemaker function have been recently described in the lower urinary tract, including the urethra, and this tumor may be related to this cellular phenotype.

Adult leydig cell tumors of the testis caused by germline fumarate hydratase mutations.

CONTEXT: Leydig cell tumors (LCTs) are the most common non-germ-cell neoplasms of the testis. LCTs are often hormonally active and can result in precocious virilization or in adult feminization. We identified an LCT in an affected individual from a kindred with hereditary leiomyomatosis and renal cell cancer (HLRCC) and a germline fumarate hydratase (FH) mutation (N64T). OBJECTIVE: Our objective was to investigate the role of FH mutations in predisposition to LCTs. DESIGN: We tested for pathogenic effects of the N64T mutation and screened an additional 29 unselected adult LCTs for FH alterations. We also tested these LCTs for mutations in two genes, the LH/choriogonadotropin receptor (LHCGR) and the guanine nucleotide-binding protein alpha (GNAS) that had been implicated in LCT tumorigenesis. RESULTS: No mutations were found in GNAS, and one tumor had a LHCGR somatic substitution. In addition to the HLRCC case with the N64T germline FH mutation, we identified one other LCT with a previously unreported FH mutation (M411I). Both LCTs from these patients showed loss of the wild-type FH allele. Immunohistochemical and in situ hybridization analyses demonstrated activation of the hypoxia/angiogenesis pathway not only in the tumors belonging to the FH mutation carriers but also in several other mutation-negative LCTs. CONCLUSIONS: Our study shows that some LCTs are caused by FH mutations and represents one of the first reports of germline mutations in any type of adult testicular tumor.

OCT4 staining in testicular tumors: a sensitive and specific marker for seminoma and embryonal carcinoma.

OCT4 (POU5F1) is a transcription factor expressed in embryonic stem and germ cells and is involved in the regulation and maintenance of pluripotency. It has been detected in primary testicular germ cell tumors with pluripotent potential, seminoma, and embryonal carcinoma. We undertook immunohistochemical staining of OCT4 in a wide variety of primary testicular neoplasms (germ cell tumors and other tumors) to assess the specificity and usefulness of this marker as a diagnostic tool. We examined histologic sections from 91 primary testicular neoplasms, including 64 cases of mixed germ cell tumors containing embryonal carcinoma (54), seminoma (51), yolk sac tumor (38), mature teratoma (31), immature teratoma (20), and choriocarcinoma (15). In addition, we examined sections from spermatocytic seminomas (5), Leydig cell tumors (8), Sertoli cell tumors (6), unclassified sex-cord stromal tumors (4), adenomatoid tumors (2), testicular tumor of adrenogenital syndrome (1), and granulosa cell tumor (1). Each tumor was examined with hematoxylin and eosin staining and with antibodies to OCT4. In all cases of mixed germ cell tumor with components of embryonal carcinoma (54) and seminoma (51), there was greater than 90% nuclear staining of the embryonal carcinoma and seminoma tumor cells with little to no background staining. In all but 1 of these cases (embryonal carcinoma), there was strong (3+) staining intensity. The other germ cell tumor components (yolk sac tumor, mature teratoma, immature teratoma, and choriocarcinoma) showed no staining. Syncytiotrophoblast cells, which were present in 15 of the cases, were also completely negative, as were all 5 of the spermatocytic seminomas. The 22 cases of non-germ cell tumors were all immunohistochemically negative for OCT4. Fifteen of the 54 germ cell tumors containing embryonal carcinoma were also examined with antibodies to CD30. These embryonal carcinoma components were all positive for CD30 with staining of greater than 90% of the tumor cells but with variable staining intensity. We conclude that immunostaining with antibodies to OCT4 is a useful diagnostic tool in the identification of primary testicular embryonal carcinomas and "usual," but not spermatocytic, seminomas. OCT4 immunostaining has comparable sensitivity but greater consistency compared with CD30 in the diagnosis of embryonal carcinoma.

Expression of ghrelin and its functional receptor, the type 1a growth hormone secretagogue receptor, in normal human testis and testicular tumors.

Ghrelin, the endogenous ligand for the GH secretagogue receptor (GHS-R), has been primarily linked to the central neuroendocrine regulation of GH secretion and food intake, although additional peripheral actions of ghrelin have also been reported. In this context, the expression of ghrelin and its cognate receptor has been recently demonstrated in rat testis, suggesting a role for this molecule in the direct control of male gonadal function. However, whether this signaling system is present in human testis remains largely unexplored. In this study we report the expression and cellular location of ghrelin and its functional receptor, the type 1a GHS-R, in adult human testis. In addition, evaluation of ghrelin and GHS-R1a immunoreactivity in testicular tumors and dysgenetic tissue is presented. The expression of the mRNAs encoding ghrelin and GHS-R1a was demonstrated in human testis specimens by RT-PCR, followed by direct sequencing. In normal testis, ghrelin immunostaining was demonstrated in interstitial Leydig cells and, at lower intensity, in Sertoli cells within the seminiferous tubules. In contrast, ghrelin was not detected in germ cells at any stage of spermatogenesis. The cognate ghrelin receptor showed a wider pattern of cellular distribution, with detectable GHS-R1a protein in germ cells, mainly in pachytene spermatocytes, as well as in somatic Sertoli and Leydig cells. Ghrelin immunoreactivity was absent in poorly differentiated Leydig cell tumor, which retained the expression of GHS-R1a peptide. In contrast, highly differentiated Leydig cell tumors expressed both the ligand and the receptor. The expression of ghrelin and GHS-R1a was also detected in dysgenetic Sertoli cell-only seminiferous tubules, whereas germ cell tumors (seminoma and embryonal carcinoma) were negative for ghrelin and were weakly positive for GHS-R1a. In conclusion, our results demonstrate that ghrelin and the type 1a GHS-R are expressed in adult human testis and testicular tumors. Overall, the expression of ghrelin and its functional receptor in human and rat testis, with roughly similar patterns of cellular distribution, is highly suggestive of a conserved role for this newly discovered molecule in the regulation of mammalian testicular function.

Leydig cell tumors of the testis with unusual features: adipose differentiation, calcification with ossification, and spindle-shaped tumor cells.

We report 19 Leydig cell tumors (LCTs) of the testis with adipose differentiation (n = 12) and/or spindle cell growth (n = 8) in patients 28-70 years of age; three tumors with adipose differentiation showed psammomatous calcifications, two of which also had foci of ossification. In eight tumors fat-like cells apparently derived from lipid accumulation within neoplastic Leydig cells and appeared as focal to prominent clusters in a background of vacuolated, neoplastic Leydig cells. The fat-like cells were usually immunoreactive for Leydig cell markers (inhibin-alpha, calretinin, and melan-A) but were typically strongly positive for the adipose tissue marker, S-100 protein, supporting a hybrid cell phenotype. Four tumors had fat of stromal derivation. In two of these there were intermixed mature adipocytes, but in two others only lipoblastic cells were present. These four tumors lacked vacuolated, neoplastic Leydig cells, and the fat cells in the single case studied were negative for inhibin-alpha and melan-A but positive for S-100. Three of the 12 LCTs with adipose differentiation were clinically malignant, and each had several of the established malignant features. Eight tumors with spindle cells occurred in men 34-70 years of age. Two tumors had ill-defined fascicles of spindle cells, and three showed prominent edematous to myxoid areas with spindle-shaped tumor cells. Two additional tumors had a fibroma-like spindled component that blended with islands of more plump, polygonal to spindle-shaped Leydig cells. Finally, one tumor had foci resembling an unclassified sarcoma that merged with conventional LCT; the spindle cell component in this case did not react for Leydig cell markers in contrast to the spindle cells in five of the six other cases in which immunostains were performed. Spindle cell differentiation, by itself, did not appear to have prognostic significance. Of the six patients with available follow-up, two developed metastases, but their tumors had malignant features apart from spindle cells; the remaining four patients were disease free at a mean of 3.6 years. Awareness of these unusual patterns in LCTs may prevent misinterpretation of fat admixed with neoplastic Leydig cells as evidence of extratesticular growth (a criterion for malignant LCT) may help avoid misdiagnosis of a LCT as a testicular "tumor" of the adrenogenital syndrome (which may contain fat) and may prevent misdiagnosis of a LCT with spindle cells as a sarcoma or unclassified sex cord-stromal tumor.

Utility of immunostaining for S-100 protein subunits in gonadal sex cord-stromal tumors, with emphasis on the large-cell calcifying Sertoli cell tumor of the testis.

This study concerns the immunohistochemical localization of S-100 alpha, S-100 beta, and whole brain S-100 (wbS-100) in testicular large-cell calcifying Sertoli cell tumor (LCCSCT). We examined 8 LCCSCTs (7 benign and 1 malignant), 6 Sertoli cell tumors not otherwise specified (SCTs-NOS), 6 Leydig cell tumors (LCTs), 5 ovarian Sertoli-Leydig cell tumors (SLCTs), and 7 gonadoblastomas (GBLs). The 8 LCCSCTs showed immunoreactivity for S-100 alpha, S-100 beta, and wbS-100. Five of the 6 LCTs and the Leydig cell components in the ovarian SLCTs stained positively for S-100 alpha and wbS-100 but were negative for S-100 beta. SCTs-NOS and the Sertoli cell components in the SLCTs occasionally showed focal and weak/moderate positivity for S-100 alpha, S-100 beta, and wbS-100. Sex cord cells of the GBLs were positive for S-100 beta and wbS-100 and negative for S-100 alpha. Germ cell elements of the GBLs were negative for S-100 alpha, S-100 beta, and wbS-100. In nonneoplastic testicular parenchyma adjacent to the above-mentioned tumors, there was S-100 alpha reactivity in Leydig cells, rete testis, and a few Sertoli cells. S-100 beta reactivity was seen in a few Sertoli cells, Schwann cells, and some endothelial cells. WbS-100 reactivity was present in Leydig cells, a few Sertoli cells, rete testis, Schwann cells, and some endothelial cells. The results indicate that S-100 alpha and S-100 beta can potentially be used as immunohistochemical markers for LCCSCT, especially when differentiating it from LCT, which may mimic LCCSCT on routine histopathology. Although the biological significance of both S-100 subunits expression in LCCSCT remains unknown, these notable calcium-binding proteins may be associated with the characteristic calcification in LCCSCT through regulation of calcium levels in the tumor cells.

Oncostatin M in the normal human testis and several testicular disorders.

The immunohistochemical reaction to oncostatin M (OSM) was studied in normal human testes at different ages (fetuses, newborns, children, pubertal boys, adults, and elderly men), as well as in several testicular disorders including carcinoma-in-situ cells (CIS), germ cell tumors, benign functioning Leydig cell tumor, androgen insensitivity syndrome, Klinefelter's syndrome, and cryptorchidism. Positive OSM immunostained Sertoli cells were only observed in fetuses. In normal testes, intense OSM immunoreaction was found in the Leydig cells of fetuses, newborns, and adults. Leydig cell immunoreaction was weak in elderly men and absent in children and pubertal boys. In some testicular disorders (Leydig cell tumor, cryptorchidism, and CIS), Leydig cell immunoreaction was as intense as in normal adult testes. This immunoreaction was heterogeneous in androgen insensitivity syndrome and was absent in Klinefelter's syndrome and intratubular seminoma. No recognizable Leydig cells were observed in the other testicular tumors. The findings of our study suggest that, in humans, the down-regulation of OSM immunoexpression in Sertoli cells occurs early, and that OSM immunoreaction in the Leydig cells is associated with functionally active and differentiated Leydig cells.

Leydig cell tumor of the testis: a clinicopathologic, DNA content, and MIB-1 comparison of nonmetastasizing and metastasizing tumors.

Leydig cell tumors of the testis are rare and account for a small proportion of testicular neoplasms. The objective of this study was to identify clinical and morphologic features predictive of metastasis in a large series of Leydig cell tumors, and to determine whether ploidy or proliferative activity were predictive of malignancy. Thirty cases of Leydig cell tumor of the testis (23 tumors that had not metastasized and 7 that had metastasized) were studied. Clinical history and follow-up were collected in all cases. The morphologic features examined included tumor size, mitotic index (mitotic figures/10 high-power fields), necrosis, angiolymphatic invasion, cell type, tumor-testicle interface, presence of extension beyond the testicular parenchyma, and presence of lipochrome and Reinke crystals. Most patients (93%) had a testicular mass. Patients with Leydig cell tumors that metastasized were diagnosed at a mean age of 62 years (range, 39-70 years) compared with 48 years (range, 9-79 years) in patients with nonmetastasizing tumors (p = 0.25). Leydig cell tumors that metastasized were significantly larger than nonmetastasizing tumors (mean, 4.7 versus 2.6 cm, respectively; p = 0.008), and had a significantly higher mitotic index (mean, 13.9 versus 1.9, respectively; p < 0.0001). Metastasizing Leydig cell tumors were significantly associated with atypical mitotic figures (p < 0.0001), nuclear variation (p = 0.0025), necrosis (p < 0.0001), angiolymphatic invasion (p = 0.009), infiltrative margins (p < 0.0001), high grade (p = 0.0004), and invasion into rete testis, epididymis, or tunica (p = 0.001) when compared with nonmetastasizing tumors. There was no significant difference between metastasizing and nonmetastasizing tumors in regard to cell type, lipochrome content, presence of Reinke crystals, or nuclear inclusions. All Leydig cell tumors that metastasized and 7 of 18 (38.9%) nonmetastasizing tumors were DNA aneuploid by static image analysis (p = 0.02). Metastasizing Leydig cell tumors had a significantly higher mean MIB-1 activity of 18.6% (range, 5.8-33.6) compared with 1.2% (range, 0.04-8.2) in nonmetastasizing tumors (p = 0.001). In this study, the presence of cytologic atypia, necrosis, angiolymphatic invasion, increased mitotic activity, atypical mitotic figures, infiltrative margins, extension beyond the testicular parenchyma, DNA aneuploidy, and increased MIB-1 activity were significantly associated with metastatic behavior in Leydig cell tumors.

Immunohistochemical study of testicular sex cord-stromal tumors, including staining with anti-inhibin antibody.

Inhibin is a peptide hormone produced by ovarian granulosa cells and testicular Sertoli cells. Ovarian granulosa cell and other sex cord-stromal tumors usually exhibit positive immunohistochemical staining with antiinhibin antibodies, and this may be valuable in differentiating these neoplasms from histologic mimics. In the present study, we investigated the immunohistochemical staining of testicular sex cord-stromal tumors using antiinhibin. Immunostaining with CAM5.2, vimentin, S-100 protein, desmin, epithelial membrane antigen (EMA), carcinoembryonic antigen (CEA), and placental alkaline phosphatase (PLAP) also was performed because few studies have investigated in detail the immunophenotype of testicular sex cord-stromal tumors. Fifteen of 16 Leydig cell tumors exhibited strong positive staining with antiinhibin. A proportion of Leydig cell tumors also stained positively with CAM5.2 (7 of 16), vimentin (14 of 16), S-100 protein (10 of 16), desmin (2 of 16) and epithelial membrane antigen (4 of 16). Four of six testicular sex cord-stromal tumors with varying degrees of Sertoli or granulosa cell differentiation were positive with antiinhibin, as were two of three sex cord-stromal tumors that were unclassified. Some of these tumors were positive with CAM 5.2, vimentin, S-100 protein, desmin, and epithelial membrane antigen. All tumors were negative with carcinoembryonic antigen and placental alkaline phosphatase. The immunohistochemical findings show that, analogous to their ovarian counterparts, most testicular sex cord-stromal tumors are immunoreactive with antiinhibin. Immunohistochemistry using this antibody as part of a panel may be valuable in confirming a diagnosis of testicular sex cord-stromal tumor and in differentiating these neoplasms from others that may mimic them.

The diagnostic utility of inhibin staining in ovarian neoplasms.

Previous immunohistologic studies have suggested that the antibody to the alpha subunit of inhibin is a sensitive marker of sex cord-stromal differentiation. However, detection has also been reported within both ovarian epithelial and germ cell tumors. To further study the normal tissue distribution of inhibin and the utility of its detection for the differential diagnosis of ovarian sex cord-stromal neoplasms, normal tissues and 225 lesions including sex cord-stromal lesions, ovarian epithelial and stromal cancers, ovarian and testicular germ cell tumors, metastases to the ovary, and non-ovarian cancers were analyzed using semi-automated immunohistochemistry. In normal tissues, immunostaining was found in cell subsets of the ovary, testis, adrenal gland, placenta, and kidney. All sex cord-stromal tumors were inhibin-positive and 37 of 50 (74%) cases exhibited at least moderate to strong immunostaining. Two cases originally diagnosed as adult granulosa cell tumors that were inhibin-negative were reassessed; diagnoses of endometrioid stromal sarcoma and endometrioid carcinoma with sertoliform features were rendered. In other primary or metastatic ovarian lesions or metastases to the ovary, weak to moderate immunostaining was found in only 4 of 84 (4.8%) cases, including ovarian clear cell carcinoma (2/2), uterine clear cell carcinomas metastatic to the ovary (1/3), and serous papillary carcinoma (1/2). Similarly, only 4 of 66 (6.1%) non-ovarian neoplasms exhibited weak immunostaining, including melanoma (1/5), uterine endometrioid carcinoma (1/2), transitional cell carcinoma (1/3), and breast adenocarcinoma (1/8). Only one case of a non-sex cord-stromal tumor had moderate or strong immunostaining. Based on these results, immunohistologic detection of the alpha subunit of inhibin is a useful adjunct in the differential diagnosis of sex cord-stromal neoplasms.

Metachronous development of malignant Leydig cell tumor.

Leydig cell tumor (LCT), a rare testicular tumor, is malignant in only about 10% of the cases. We report the case of a patient with bilateral malignant LCTs that developed metachronously. After undergoing a right inguinal orchiectomy for a malignant LCT at the age of 43 years, the patient was given cisplatin-based chemotherapy for suspected para-aortic lymph node metastasis. Eighteen months after the right orchiectomy, examination of a left testicular biopsy specimen showed a malignant LCT and a left inguinal orchiectomy was performed. Histologically, the initial malignant LCT exhibited a highly pleomorphic appearance with mitotic figures (58/10 HPF), whereas the second malignant LCT showed fewer mitoses (2/10 HPF). The proliferating cell nuclear antigen (PCNA)-labelling index in these tumors also differed (right-sided tumor, 50%; left-sided tumor, 28%). These findings suggest that the malignant LCT in the left testis developed as a second primary rather than as a metastatic tumor. There have been no known similar cases, although three cases of malignant LCT with contralateral metastasis have been reported.

Neuroendocrine characteristics of human Leydig cell tumours.

The neuroendocrine nature of a subset of Leydig cells has already been established. The present investigation deals with neuroendocrine characteristics of Leydig tumour cells. A number of neuroendocrine and neuronal markers were demonstrated in Leydig cell tumours of 7 men aged 25-41 years. The following substances were immunocytochemically tested in Leydig tumour cells: the monoamine-synthesizing enzymes tyrosine hydroxylase and aromatic L-amino acid decarboxylase, the indoleamine serotonin, the calcium-binding protein parvalbumin, the microtubule associated protein-2, neurofilament protein 200, synaptophysin, neuron specific enolase, substance P and neuronal nitric oxide synthase (NOS). Compared to the normal interstitial cells beyond the tumours, all neoplastic cells showed a significantly weaker immunoreactivity for nerve cell markers as well as for testosterone and cyclic guanosine monophosphate (cGMP), which is usually accumulated by nitric oxide (NO). This provides evidence for a certain dedifferentiation of Leydig tumour cells. However, these results suggest that tumourous development of Leydig cells does not include loss of neuronal phenotype. Moreover, on the assumption that 'neuronal' Leydig cells exist beside 'non-neuronal' ones in normal testicular tissue, we propose the hypothesis that 'neuronal' Leydig cells can transform to tumour cells.

Virilizing stromal Leydig cell tumor (Leydig cell-containing thecoma) of the ovary in pregnancy. A case report with extensive immunohistochemical investigation of the tumor cells.

The rare case of a stromal Leydig cell tumor of the ovary occurring in a 21-year-old woman who developed signs of virilization during pregnancy is reported. Serum androgen levels were markedly elevated. At cesarean section, a slightly hypotrophic, but otherwise normal, female infant was delivered and a tumor of the right ovary measuring 12 cm in maximum diameter was resected. Histologic examination revealed a sex cord-stromal tumor consisting of spindle-shaped, thecomatous cells and a large number of loosely scattered clusters of large polygonal cells with abundant eosinophilic cytoplasm. Both types of tumor cells were strongly immunoreactive for vimentin, but exhibited no proliferative activity and no overexpression of p53 protein. A few of the polygonal cells contained typical crystalloids of Reinke. Cellular atypia was not a prominent feature, and a diagnosis of benign stromal Leydig cell tumor was established. As expected, 20 months after diagnosis the patient exhibits no signs of recurrence or dissemination. To the best of our knowledge this is only the second case of a stromal Leydig cell tumor occurring in pregnancy to be described.

Laminin expression in testicular tumours of the dog.

The expression of laminin was studied to determine the distribution pattern of basement membranes (BMs) in normal testes and in a series of 40 canine testicular tumours (seminomas, Leydig and Sertoli cell tumours). BM was always present around seminiferous tubules and blood vessels in normal testes and in seminomas and Sertoli cell tumours of the intratubular type without invasion. BM changes (fragmentation or loss, or both) were usually found in invasive neoplasms which retained their tubular structure; disruption or absence was observed in tumours, with a diffuse pattern. The BM was never expressed in Leydig cell tumours, except around vessels, irrespective of their histological growth pattern (cystic-vascular, pseudoadenomatous, diffuse). An attempt was made to relate the degree of BM modification to proliferative monoclonal antibodies and mitotic index. In parallel with the progressive loss of BM an increase in proliferative activity occurred, indicating that BM changes are additional useful prognostic indicators in testicular tumours of the dog.

Occurrence of FSH, inhibin and other hypothalamic-pituitary-intestinal hormones in normal fertility, subfertility, and tumors of human testes.

OBJECTIVE: To compare the distribution of peptide hormones in presumably normal human testicular tissues and specimens exhibiting any of five pathologies. METHODS: Biopsies from patients having testicular malfunctions were prepared as sections and specifically immunohistochemically stained for inhibin, FSH, serotonin, AUP, and oxytocin. RESULTS: Immunocytochemical studies revealed the presence of various hypophysial-pituitary-intestinal hormones, viz., FSH, inhibin, arginine vasopressin (AVP), calcitonin, serotonin, oxytocin, adrenocorticotropin (ACTH), gastrin, secretin, and somatostatin in human testicular biopsies exhibiting normal spermatogenesis, Sertoli-cell-only syndrome, spermatogenic arrest, Leydig cell hyperplasia, Leydig cell tumor, and seminoma. Intensity of immunostaining for all peptides except FSH was stronger in cases of subfertile as compared to normal testis. Intensity of immunostaining with inhibin was maximum in Leydig cell tumor. CONCLUSION: These regulatory peptides may be involved in the pathophysiology of the testes.

Acute action of choriogonadotropin on Leydig tumor cells: induction of a higher affinity benzodiazepine-binding site related to steroid biosynthesis.

We previously demonstrated that the mitochondrial peripheral-type benzodiazepine receptor (PBR) is coupled to hormone-activated steroidogenesis by regulating the intramitochondrial cholesterol transport, the rate-determining step of steroid biosynthesis. In the present study we examined whether PBR is the site of hormone action using the hCG-responsive MA-10 mouse Leydig tumor cell line as a model system. Within 15 sec of the addition of hCG to Leydig cells a 3-fold cAMP-dependent increase in PBR binding was observed. This rapid increase returned to basal levels within 60 sec. No effect was observed after 1 min in the continued presence of hCG. Scatchard analysis revealed that in addition to the known high affinity (5.0 nM) benzodiazepine-binding site, a second, hormone-induced, higher affinity (0.2 nM) benzodiazepine-binding site appeared. We then examined whether in such a short time frame steroid synthesis occurs. Fifteen-second incubation of MA-10 cells with the inhibitor of cholesterol metabolism aminoglutethimide together with hCG also resulted in an increased rate of pregnenolone formation by their isolated mitochondria that were washed and incubated in aminoglutethimide-free buffer. The dose response of benzodiazepine binding to hCG closely parallels the increase in steroid formation by the mitochondria of stimulated cells. Addition of the selective inhibitor of cAMP-dependent protein kinase, H-89, completely blocked hormone-induced PBR binding and steroid formation, whereas addition of the inactive analog H-85 was without any effect. The addition of flunitrazepam, a benzodiazepine previously shown to inhibit the trophic hormone action on steroidogenesis, completely abolished the hCG-induced rapid stimulation of steroid synthesis. These results demonstrate that in MA-10 cells, the most rapid effect described thus far of hCG and cAMP, is the transient induction of a higher affinity benzodiazepine-binding site, which occurs concomitantly with an increase in the rate of steroid formation. This, in turn, suggests that these hormones alter PBR to activate cholesterol delivery to the inner mitochondrial membrane and subsequent steroid formation.

Leydig cell tumor: estradiol level at different locations.

The authors report on estradiol levels at different locations in a patient with a Leydig cell tumor. The highest value was found in the testicular vein. The estradiol level was, however, ten times higher in the peritesticular vaginal fluid than in the peripheral veins.