Regression Of Mullerian Ducts Research Articles

The Anti-Mullerian hormone and ovarian cancer

The Anti-Mullerian hormone (AMH), which is produced by fetal Sertoli cells, is responsible for regression of Mullerian ducts, the anlagen for uterus and Fallopian tubes, during male sex differentiation. Ovarian granulosa cells also secrete AMH from late in fetal life. The patterns of expression of AMH and its type II receptor in the post-natal ovary indicate that AMH may play an important role in ovarian folliculogenesis. Recent advances in the physiological role of AMH has stimulated interest in the significance of AMH as a diagnostic marker and therapeutic agent for ovarian cancer. Currently, AMH has been shown to be a circulating marker specifically for granulosa cell tumour (GCT). Its diagnostic performance seems to be very good, with a sensitivity ranging between 76 and 93%. In patients treated for GCT, AMH may be used post-operatively as marker for the efficacy of surgery and for disease recurrence. Based on the physiological inhibitory role of AMH in the Mullerian ducts, it has been proposed that AMH may inhibit epithelial ovarian cancer cell both in vitro and in vivo. These observations will be the basis for future research aiming to investigate the possible clinical role of AMH as neo-adjuvant, or most probably adjuvant, therapy for ovarian cancer.

Mullerian Inhibiting Substance enhances subclinical doses of chemotherapeutic agents to inhibit human and mouse ovarian cancer

Mullerian Inhibiting Substance (MIS), a biological modifier that causes regression of Mullerian ducts in male embryos, is effective as a single agent in vitro and in vivo against human and mouse ovarian cancer cell lines expressing MIS type II receptor; however, little is known about how recombinant human MIS (rhMIS), now being scaled for preclinical trials, could be used in combination with cytotoxic or targeted chemotherapeutic agents. Mouse serous and endometrioid ovarian carcinoma cell lines were tested in vitro against rhMIS alone and with doxorubicin, paclitaxel, or cisplatin as agents in clinical use. Because MIS releases FK506 binding protein (FKBP12), which activates the mammalian target of rapamycin (mTOR) downstream of Akt, rhMIS and rapamycin combinations were tested. MIS increases p16 protein levels, and 5'-Aza-2'-deoxycytidine (AzadC) induces p16 mRNA; therefore, they were used in combination in vitro and in vivo with a human ovarian cancer cell line. A paclitaxel-resistant human ovarian cancer cell line and its parental line both respond to rhMIS in vitro. Additivity, synergy, or competition was observed with MIS and rapamycin, AzadC, doxorubicin, cisplatin, and paclitaxel, suggesting that MIS in combination with selective targeted therapies might achieve greater activity against ovarian cancer than the use of each individual agent alone. These assays and statistical analyses could be useful in selecting rhMIS and chemotherapeutic agent combinations that enhance clinical efficacy and reduce toxicity.

Recombinant Human Mullerian Inhibiting Substance Inhibits Long-term Growth of MIS Type II Receptor–Directed Transgenic Mouse Ovarian Cancers In vivo

Mullerian inhibiting substance (MIS) is a glycoprotein hormone that causes Mullerian duct regression in male embryos. In short-term experiments, recombinant human MIS (rhMIS) inhibits xenotransplanted human ovarian cancer cell lines that are thought to be of Mullerian origin. Because this highly lethal cancer has a high recurrence rate after conventional chemotherapy, new treatments are warranted. We examined whether rhMIS as a novel, nontoxic, naturally occurring growth inhibitor can be an effective anticancer drug in long-term studies in vivo against allograft tumors that recapitulate human ovarian carcinoma. Mouse ovarian carcinoma (MOVCAR) cell lines expressing the early region of the SV40 virus, including the large and small T-antigen genes under transcriptional control of a portion of the murine MIS receptor type II (MISRII) gene promoter, were derived from TgMISIIR-TAg transgenic mice. rhMIS was tested against MOVCAR cells in growth inhibition assays in vitro, and in vivo in 6-week-old female nude mice. Tumor growth in animals was measured at weekly intervals for up to 20 weeks. MOVCAR cells and tumors express MISRII by Western blot, immunohistochemical, and Northern blot analyses. rhMIS significantly inhibited MOVCAR cell growth in vitro and in vivo in three separate long-term allotransplantation experiments. Because rhMIS is an effective anticancer agent in in vitro and in long-term in vivo preclinical experiments against MISRII-positive tumors, we predict that rhMIS can be used safely and effectively to treat human ovarian malignancies.

Pubertal and Adult Leydig Cell Function in Mullerian Inhibiting Substance-Deficient Mice

Mullerian inhibiting substance (MIS) causes Mullerian duct regression during sexual differentiation and regulates postnatal Leydig cell development. MIS knockout (MIS-KO) mice with targeted deletions of MIS develop Leydig cell hyperplasia, but their circulating androgen concentrations are reportedly unaltered. We compared reproductive hormone profiles, androgen biosynthesis, and the expression of key steroidogenic and metabolic enzymes in MIS-KO and wild-type (WT) mice at puberty (36 d) and sexual maturity (60 d). In pubertal animals, basal testosterone and LH concentrations in plasma were lower in MIS-KO than WT mice, whereas human chorionic gonadotropin-stimulated testosterone concentrations were similar. In adults, basal LH, and both basal and human chorionic gonadotropin (hCG)-stimulated testosterone concentrations were similar. Purified Leydig cells from pubertal MIS-KO mice had lower testosterone but higher androstanediol and androstenedione production rates. In contrast, testosterone, androstanediol, and androstenedione production rates were all lower in adult MIS-KO Leydig cells. Steroidogenic acute regulatory protein expression was lower in pubertal MIS-KO mice compared with WT, whereas 17beta-hydroxy-steroid dehydrogenase and 5alpha-reductase were greater, and P450c17 and P450scc were similar. The expression of steroidogenic acute regulatory protein and 17beta-hydroxysteroid dehydrogenase was lower in adult MIS-KO mice, whereas that of 5alpha-reductase, P450c17, and P450scc was similar. Collectively, these results suggest that in the absence of MIS, Leydig cells remain less differentiated, causing an altered intratesticular androgen milieu that may contribute to the infertility of MIS-KO mice. In immature mice, this deficit in steroidogenic capacity appears to be mediated by a direct loss of MIS action in Leydig cells as well as by indirect effects via the hypothalamic-pituitary-gonadal axis.

Synergistic Cooperation between the β-Catenin Signaling Pathway and Steroidogenic Factor 1 in the Activation of the Mullerian Inhibiting Substance Type II Receptor

Mullerian inhibiting substance type II receptor (MISRII) is a member of the transforming growth factor-beta superfamily. Mutations in mullerian inhibiting substance (MIS) or MISRII cause male sexual abnormalities, persistent mullerian duct syndrome, and pseudohermaphroditism. The spatial and temporal regulation of MIS and MISRII is important for its biological action. Male Wnt7a mutant mice do not undergo regression of mullerian ducts. Here we showed that the canonical Wnt signaling pathway regulated MISRII. The promoter MISRII was activated by beta-catenin expression, and this activation was dependent on TCF4-binding sites. The nuclear receptor superfamily member steroidogenic factor 1 (SF1) synergistically activated the MISRII promoter with beta-catenin. APC, a negative regulator of Wnt signaling, decreased SF1-mediated activation of the MISRII promoter in the colon carcinoma cell line SW480. We also showed a direct physical interaction between beta-catenin and SF1 by co-immunoprecipitation. Thus, our findings suggest that MISRII is a developmental target of Wnt7a signaling for mullerian duct regression during sexual differentiation.

A Man with Uterine Leiomyoma

In the human male fetus, testes develop by the 7th week and begin to secrete two hormones: antimullerian hormone (AMH) induces the regression of mullerian ducts, the analogue of the uterus, fallopian tubes and upper vagina, upon binding to a specific membrane receptors, whereas testosterone induces the differentiation of the wolffian ducts into the epididymes, vasa deferentia and seminal vesicles(1).

From malformations to molecular mechanisms in the male: three decades of research on endocrine disrupters

For three decades, we have known that estrogens alter the development of the mammalian reproductive system in predictable ways. In mice exposed prenatally to diethylstilbestrol (DES) or other estrogens, the male offspring exhibit structural malformations including cryptorchidism, epididymal cysts and retained Mullerian ducts. The estrogen‐associated alterations in the genital tract phenotype can be usefully considered as a model called Developmental Estrogenization Syndrome. While estrogen treatment during critical periods of morphogenesis of the male reproductive system has been associated with these changes, the mechanisms at the molecular level are still being discovered. Parallel findings on the hormones involved in Mullerian duct regression and testicular descent have helped guide research on the mechanisms of developmental estrogenization of the male. Cellular localization of molecular signals associated with key steps in genital tract development, use of mice with gene disruption, and knowledge of the mechanisms underlying persistent changes in gene expression are beginning to provide a blue print for both the physiological role and pathological effects of estrogens in reproductive tract development. Since many of the same biological principles underlie genital tract morphogenesis in mammals, one may expect some of the same changes in males of other species exposed to estrogen during the appropriate developmental periods.

From malformations to molecular mechanisms in the male: three decades of research on endocrine disrupters.

For three decades, we have known that estrogens alter the development of the mammalian reproductive system in predictable ways. In mice exposed prenatally to diethylstilbestrol (DES) or other estrogens, the male offspring exhibit structural malformations including cryptorchidism, epididymal cysts and retained Mullerian ducts. The estrogen-associated alterations in the genital tract phenotype can be usefully considered as a model called Developmental Estrogenization Syndrome. While estrogen treatment during critical periods of morphogenesis of the male reproductive system has been associated with these changes, the mechanisms at the molecular level are still being discovered. Parallel findings on the hormones involved in Mullerian duct regression and testicular descent have helped guide research on the mechanisms of developmental estrogenization of the male. Cellular localization of molecular signals associated with key steps in genital tract development, use of mice with gene disruption, and knowledge of the mechanisms underlying persistent changes in gene expression are beginning to provide a blue print for both the physiological role and pathological effects of estrogens in reproductive tract development. Since many of the same biological principles underlie genital tract morphogenesis in mammals, one may expect some of the same changes in males of other species exposed to estrogen during the appropriate developmental periods.

Antimullerian hormone

Antimullerian hormone (АМН) (also called Mullerian Inhibiting Substance) is the gonadal hormone. It is a member of the transforming growth factor-bb family of peptide growth and differentiation factors. АМН is produced in both male and female gonads - by Sertoli cells of the testis and granulosa cells of the ovaries. During the male embryogenesis АМН causes regression of Mullerian ducts, and testosterone stimulate the differentiation of wolffian system. During female embryogenesis, in the absence of АМН and testosterone, mullerian structures differentiate and develop into female internal genitalia and wolffian ducts regress.
 АМН continues to be produced by the granulosa cells of the ovary during the reproductive life of the women. АМН is known to inhibit resumption of meiosis in oocytes. Besides, АМН disturbs ovarian steroidogenesis: it decreases aromatase activity, leading to lowered estradiol production and hyperandrogenia in the follicle. АМН inhibits granulosa cells mitosis and decreases the number of LH-receptors on the granulosa cells. АМН is the antagonist of Epidermal Growth factor ( EGF) and might inhibit EGF-stimulated secretion of tissue-type plasminogen activator (tPA), which plays significant role in the ovulatory rupture of the follicle.
 Thus, АМН exerts inhibitory influence on all follicular components, including granulosa cells growth, steroidogenesis, oocyte maturation and follicle rupture process. It suggests, that АМН might play certain role in pathogenesis of chronic anovulation (polycystic ovaries syndrome).

Effect of anti-Mullerian hormone on Sertoli and Leydig cell functions in fetal and immature rats.

Anti-Mullerian hormone (AMH) is mainly involved in the regression of Mullerian ducts in male fetuses, but it may have other functions linked to gonadal development. The present study examines the effect of AMH on steroidogenesis by Sertoli and Leydig cells in fetal and immature rats during the period where AMH is physiologically produced in the testis. The basal aromatase activity of Sertoli cells in primary culture was strongly stimulated (77-91%) by cAMP. AMH (35 nM) reduced cAMP-stimulated aromatase activity by 49-69% as early as fetal day 16 and until postnatal day 20. This effect was dose dependent and was seen after 48 h in culture. AMH also blocked the Sertoli cell aromatase activity stimulated by FSH, but LH did not stimulate this activity, confirming that the aromatase activity effectively resulted from Sertoli cells and not from contaminating Leydig cells. RT-PCR analysis showed that AMH reduced aromatase activity by decreasing the amount of aromatase messenger RNA. AMH also inhibited the LH-stimulated testosterone production by dispersed fetal Leydig cells in culture in a dose-dependent manner. The inhibitory effect of AMH did not depend on the fetal stage studied (16 or 20 days postconception) and resulted from a drop in the steroidogenic activity of each Leydig cell without affecting the number of 3beta-hydroxysteroid dehydrogenase-positive cells. These data provide the first evidence that AMH, like other members of the transforming growth factor-beta family, has an autocrine/paracrine effect on testicular steroidogenic function during the fetal and prepubertal periods.

Serum Levels of Mullerian Inhibiting Substance in Preterm and Term Male Neonates

Purpose Mullerian inhibiting substance, also called anti-mullerian hormone, is responsible in the embryo for the regression of the mullerian structures. During the second and third trimesters the physiological functions that mullerian inhibiting substance may have after the period of mullerian duct regression are poorly understood. We obtained information on mullerian inhibiting substance levels in the male newborn during this period of gestation. Materials and Methods Mullerian inhibiting substance was measured by an enzyme immunoassay in cord blood obtained at birth in 27 preterm (25 to 36 weeks of gestation) and 92 term (37 to 42 weeks) male neonates. Results Cord serum mullerian inhibiting substance concentrations were relatively high from 25 to 31 weeks (mean plus or minus standard deviation 86.4 +/− 36.1 ng./ml.) and then they decreased from 32 weeks to term (mean 24.2 +/− 14.0 ng./ml.). Conclusions The decline early in the third trimester may be consistent with mullerian inhibiting substance having a function during the second but a diminished role in the third trimester.

Hormone-dependent cancer

The recent demonstrations that Mullerian inhibiting substance (MIS) is present in embryonic chick ovaries (P. K. Hutson, H. Ikawa, and P. K. Donahoe (1981). J. Pediatr. Surg. 16, 822–827), and that exogenous diethylstilbestrol does not significantly inhibit MIS secretion from feminized testes (Hutson et al. (1982) J. Pediatr. Surg. 17, 953–959), suggest that ovarian estrogens protect the female left Mullerian duct from MIS-induced regression. The possibility exists, however, that ovarian MIS may be inactive. This study was designed to see if interference with estrogen action in ovo would allow MIS to cause regression of the female left Mullerian duct. The “antiestrogens,” tamoxifen and LY117018, had little effect on the female Mullerian ducts unless given in high doses or with added testosterone (>0.1 mg). Two compounds known to inhibit estrogen synthesis, aminoglutethimide and 4-hydroxyandrostenedione, had no effect on their own, even in high dose (<1.0 mg/egg). However, when administered together (0.5 mg each) there was significant disappearance of the lower ends of both Mullerian ducts. Norethindrone, which has been described recently as an aromatase inhibitor (Y. Osawa, C. Yarborough, and V. Osawa (1982). Science (Washington, D.C.) 215, 1249–1251) caused partial regression of the upper end of the left Mullerian duct as well as complete loss of the lower ends of both ducts in the female. These results suggest that the steroid environment is a critical factor in the response of the Mullerian ducts to MIS, and that estrogen blockage may allow endogenous MIS from the ovary to induce partial regression of the Mullerian ducts in the female chick embryo.

DiI Analysis of Cell Migration during Mullerian Duct Regression

In most male vertebrates, the Mullerian ducts, which are the embryonic oviducts, regress completely during embryogenesis or shortly thereafter. Mullerian duct regression is caused by the testicular hormone Mullerian inhibiting substance. While the exact mechanism of Mullerian duct regression is not well understood, it is theorized to involve active migration of at least some of the ductal epithelial cells following breakdown of the basement membrane, possibly through an interaction between the epithelial cells and the surrounding extracellular matrix. The purpose of the present study was (1) to confirm that Mullerian duct regression is characterized by epithelial cell migration and (2) to determine the destination of these cells. The ductal epithelium of male alligator embryos was labeled with the fluorescent cell marker DiI and then allowed to undergo regression in vitro. DiI-labeled Mullerian ducts from female embryos served as controls. An in vivo experiment also was performed in which the Mullerian ducts of female hatchlings were injected with DiI prior to each female receiving a testicular implant from a male hatchling. Control females received a kidney implant instead. In both the in vitro and the in vivo experiments, DiI-labeled epithelial cells were observed migrating out from the duct during regression. In the in vitro experiment in which regression proceeded more rapidly, epithelial cells entered the mesonephric kidneys and were incorporated into the nephric tubule epithelium. No regression or cell migration was observed in the control Mullerian ducts.

Gonadal migration in ambiguous genitalia

Correlation of the gonadal position and mullerian duct derivative regression was estimated in 17 patients with ambiguous genitalia and dysgenetic gonads. Six out of ten testes located at or beyond the internal inguinal ring were not associated with fallopian tubes on the same side. Four of those six testes were cryptorchid, including two that were located at the internal inguinal ring. All six intra-abdominal testes were associated with an ipsilateral fallopian tube. These findings can be explained by the two-stage model of testicular descent where migration from the posterior abdominal wall to the internal inguinal ring, the transabdominal phase, is closely related to mullerian duct regression, suggesting a role for mullerian inhibiting substance in this phase.

Extended Production of the Mullerian Duct Regressor in the American Alligator

Regression of the Mullerian ducts in mammals and birds is caused by the testicular hormone, Mullerian inhibiting substance (MIS), which is produced for an extended period of time after testicular differentiation. Because it is present long after the ducts regress, it has been proposed to have additional effects other than inducing Mullerian duct regression. A testicular substance also appears to be responsible for Mullerian duct regression in the alligator based on studies in which testicular grafts from hatchling males caused regression when implanted into castrated hatchling females. In this study, the approximate ontogeny of the regressor in the alligator was investigated by implanting testicular grafts from both hatchling and yearling males into castrated female hatchlings. Histological quantification of the ducts revealed that regression in both treatment groups was not significantly different indicating that the Mullerian duct regressor in the alligator is produced for at least a year after hatchling and may have additional nonregressive functions in the alligator as has been proposed for mammals and birds.

Mullerian-inhibiting substance secretion is delayed in XX sex-reversed dog embryos.

Sertoli cell secretion of Mullerian-inhibiting substance (MIS) begins shortly after testis differentiation. Mullerian ducts regress following MIS exposure during an embryonic critical period. In dogs with XX sex reversal, Mullerian ducts persist in the presence of testicular tissue. This study was conducted to determine whether MIS is present in ovotestes of XX sex-reversed embryos during the period for Mullerian duct regression in normal males. XX sex-reversed embryos and normal littermates were identified by a combination of karyotype and gonadal histology. The degree of regression in the adjacent Mullerian duct was scored. Immunohistochemical staining was used to detect MIS in the contralateral gonad. Testicular differentiation and MIS secretion were identified in XY embryos at all ages studied (35-46 days). Seminiferous tubules were not observed in gonads of embryos at risk of XX sex reversal between 35-38 days (n = 15), but were observed at 40 and 46 days (n = 3). Although positive staining for MIS was observed in ovotestes, adjacent Mullerian ducts persisted. The degree of seminiferous tubule development was reduced and MIS secretion was delayed in ovotestes, compared to normal testes. Mullerian duct persistence in this model is apparently due to an abnormality in the quantity and timing of MIS secretion during embryonic development.

MULLERIAN INHIBITING SUBSTANCE EIA IS YIELDING NEW INSIGHTS INTO GONADAL PHYSIOLOGY AND PATHOLOGY

Mullerian inhibiting substance (MIS) is a testicular hormone made by fetal and postnatal Sertoli cells, and causes Mullerian duct regression during male sexual dilferentiauon. We established an EIA to measure MIS scrum levels in a number of physiological and pathological conditions. Significant levels of serum MIS are found in normal males during the first year of life (1). MIS levels decline throughout childhood and are undeteclable after pubertal development (2). MIS levels were examined in patients previously diagnosed with Hodgkin's Lymphoma. Nine adults (>16 years) had low bui measurable levels of MIS. Patients with Hodgkin's Lymphoma have azospermia, suggesting a possible link between MIS secretion and the spermalogonia. In very low birth weight babies (>1500g). MIS levels in cord sera were significantly higher than in full-term controls (79125μg/L vs 36±8μg/L; P<0.001). MIS levels also were examined previously in infants and boys with cryptorchidism, where the levels during the first year were significantly lower than normal (3). This suggested a possible link between MIS and germ cell maturation. which is occurring at that time. Recently we have confirmed experimentally that MIS does stimulate germ cell maturation in the neonatal mouse testls in vitro. (1) Baker ML, Metcalfe SM & Hutson JM. J Clin Endocrin Metab. 1990; 70: 11-15. (2) Baker ML & Hulson JM. J Clin Endocrin Metab (In Press) (3) Yamanaka J, Baker ML, Metcalfe SM & Hutson JM. J Pediatr Surg. 1991; 26: 621-623

Effect of human recombinant mullerian inhibiting substance on isolated epithelial and mesenchymal cells during mullerian duct regression in the rat.

The effect of human recombinant Mullerian Inhibiting Substance (MIS) on the regression of the Mullerian duct (MD) of female rat fetuses was examined in vitro to determine whether MIS acts on MD epithelium and/or mesenchyme at the critical periods of sexual differentiation. Urogenital ridges (URs) of female rat fetuses at 14.5- to 18.5-days of gestation (plug day = 0) were cultured for 3 days with or without recombinant human MIS in CMRL 1066 medium with 10% female fetal calf serum. In URs from 14.5- and 15.5-day-old fetuses, the cranial portion of the MD regressed almost completely during the 3-day culture period in the presence of MIS, whereas the caudal half to third of the MD remained intact but tapered to a fine point cranially. MDs survived in URs from 16.5-day-old fetuses cultured in the presence of MIS except that the cranial portion of the MDs was deformed. MIS did not elicit regression of MDs in URs obtained from 17.5- and 18.5-day-old fetuses, but instead caused the MD epithelium to form bulges projecting into the mesenchyme. MD epithelium at 15.5-days of gestation was separated from the surrounding UR mesenchyme, and both components (MD epithelium and mesenchyme) were cultured separately for 3 days in the presence or absence of MIS. Both epithelial and mesenchymal cells survived in the presence or absence of MIS. MD epithelium formed typical epithelial colonies, whereas UR mesenchyme spread as fibroblastic cells. Analysis of labeling index after incorporation of [3H] thymidine demonstrated that MD epithelial DNA synthesis was not influenced by MIS. In contrast, mesenchymal labeling index was reduced significantly by MIS. This effect of MIS on UR mesenchyme in conjunction with earlier histological observations of mesenchymal condensation during MD regression and an absence of direct effects of MIS on the epithelium suggests that MIS elicits its effect on the MD epithelium via the surrounding mesenchyme.

Effect of human recombinant mullerian inhibiting substance on isolated epithelial and mesenchymal cells during mullerian duct regression in the rat

The effect of human recombinant Mullerian Inhibiting Substance (MIS) on the regression of the Mullerian duct (MD) of female rat fetuses was examined in vitro to determine whether MIS acts on MD epithelium and/or mesenchyme at the critical periods of sexual differentiation. Urogenital ridges (URs) of female rat fetuses at 14.5- to 18.5-days of gestation (plug day = 0) were cultured for 3 days with or without recombinant human MIS in CMRL 1066 medium with 10% female fetal calf serum. In URs from 14.5- and 15.5-day-old fetuses, the cranial portion of the MD regressed almost completely during the 3-day culture period in the presence of MIS, whereas the caudal half to third of the MD remained intact but tapered to a fine point cranially. MDs survived in URs from 16.5-day-old fetuses cultured in the presence of MIS except that the cranial portion of the MDs was deformed. MIS did not elicit regression of MDs in URs obtained from 17.5- and 18.5-day-old fetuses, but instead caused the MD epithelium to form bulges projecting into the mesenchyme. MD epithelium at 15.5-days of gestation was separated from the surrounding UR mesenchyme, and both components (MD epithelium and mesenchyme) were cultured separately for 3 days in the presence or absence of MIS. Both epithelial and mesenchymal cells survived in the presence or absence of MIS. MD epithelium formed typical epithelial colonies, whereas UR mesenchyme spread as fibroblastic cells. Analysis of labeling index after incorporation of [3H] thymidine demonstrated that MD epithelial DNA synthesis was not influenced by MIS. In contrast, mesenchymal labeling index was reduced significantly by MIS. This effect of MIS on UR mesenchyme in conjunction with earlier histological observations of mesenchymal condensation during MD regression and an absence of direct effects of MIS on the epithelium suggests that MIS elicits its effect on the MD epithelium via the surrounding mesenchyme.

Directed expression of an oncogene to Sertoli cells in transgenic mice using mullerian inhibiting substance regulatory sequences.

Mullerian inhibiting substance (MIS) is a glycoprotein hormone expressed by Sertoli cells that induces the regression of Mullerian ducts during development of the male reproductive tract. Transgenic mice carrying a fusion gene composed of human MIS transcriptional regulatory sequences linked to the SV40 T-antigen gene specifically develop testicular tumors composed of a cell type histologically resembling the Sertoli cell. The lack of pathology at other sites suggests tissue-restricted expression of the transgene. A cell line derived from one of the testicular tumors has been established that continues to express markers associated with Sertoli cells, such as transferrin, sulfated glycoprotein-2, and inhibin-beta B. The cell line does not express detectable levels of inhibin-alpha, MIS, or FSH receptor. However, the cells have retained forskolin responsiveness. As adult Sertoli cells cannot be propagated in vitro, the availability of an immortal cell line displaying features characteristic of normal Sertoli cells should aid in subsequent analyses of the biology of this cell type.