Mullerian Inhibiting Substance Levels Research Articles

Breast cancer risk coordinators: Artificial intelligence-based density measurement and Mullerian-inhibiting substance.

Due to its increasing prevalence, breast cancer has become a serious public health problem. In addition to the models used to identify individuals at risk, the search for fast and accurate tools has continued for years. In our study, we aimed to examine the correlation of mammographic density measurement and serum Mullerian-inhibiting substance (MIS) levels with an effective model such as Gail. Of the women whose serum MIS levels were measured in the last 1year, 214 participants who applied for routine breast examination were included in the study. The age range was between 40 and 60. Exclusion criteria were determined as pathological mammographic findings, active breast symptom, and thoracic radiotherapy history. Mammographic density measurement (PD) was performed with the artificial intelligence-based Deep-LIBRA software. The relationship of these two parameters with the lifetime risk of developing breast cancer was examined. The correlation between PD and GRP was remarkable (p < 0.01cc:0.35). A positive correlation was observed between serum MIS levels and increased breast cancer, but it was not possible to prove this statistically (p = 0.056). It was thought that this situation was caused by perimenopausal patients. Because when the menopause group was excluded, the correlation between MIS levels and GRP decreased (p = 0.12cc:0.17). PD measurement can be considered as a promising method for the determination of individuals at risk for breast cancer in a large group of patients, but we think that serum MIS levels are not suitable for risk assessment in perimenopausal patients.

Abstract AS25: An adeno-associated virus (AAV) 9 vector delivering modified human mullerian inhibiting substance (MIS) as a gene therapy for ovarian cancer

Abstract Purpose: Ovarian cancer is the most lethal malignancy of the female reproductive tract; as such, effective treatments are needed to improve patient survival. MIS has previously been shown to inhibit growth of a stem-like subset of the total cell population in ovarian cancer cell lines (Wei et al, 2010; Meirelles et al, 2012). We have recently engineered novel peptide modifications to human MIS (LR-MIS), which increase production and potency in vitro and in vivo (Pepin et al, 2013), and inserted it into an AAV vector. AAV delivered gene therapy has undergone a clinical resurgence with a good safety profile and sustained gene expression (Zhang et al, 2011). Therefore, we assessed the efficacy of a single intraperitoneal (ip) dose of AAV9-LR-MIS to inhibit tumor growth of an established cell line for subsequent evaluation in patient-derived ovarian cancer xenografts (PDX). Methods: 6 week old female nude mice were treated with a single ip injection of 3e11 or 1e12 virions of AAV9 LR-MIS or GFP. Serum levels of human MIS were monitored weekly by ELISA. After serum steady state was achieved, the established ovarian cancer cell line, OVCAR5 was xenografted subcutaneously at 1e6 cells per animal. Tumors treated with AAV were measured twice weekly. Additionally, Patient ascites were processed to isolate the cancer cell population, which was specifically amplified in vitro to create low passage primary cell lines. Results: AAV9-LR-MIS treatment resulted in elevated and sustained blood concentrations of MIS (Fig1A) in nude mice without any signs of toxicity, and significantly inhibited OVCAR5 tumor growth (p=0.0003) (Fig1B) in two separate experiments. AAV9-GFP revealed that the pancreas, omentum, gut mesentery, and body wall muscles were the primary sites of infection. Treatment with MIS induced downregulation of CCND1 in tumors. A panel of 15 primary ovarian cancer cell lines, all expressing the MIS type II receptor were generated from patient ascites and cells are being tested for their ability to grow as PDX in Nude, NOD/SCID, and NSG mice. Figure 1.AAV-LR-MIS treatment results in stable expression of MIS and inhibition of tumor growth of OVCAR5 xenografts. A) Weekly MIS ELISA of serum from mice after single doses of 1e10 to 1e12 virions. B) Tumor growth of 1e6 OVCAR5 cells xenografted into nude mice (N=5) pretreated with 3e11/mouse (1.5e13/kg) LR-MIS or GFP virus (p=0.0003 by two-way ANOVA).Figure 1. AAV-LR-MIS treatment results in stable expression of MIS and inhibition of tumor growth of OVCAR5 xenografts. A) Weekly MIS ELISA of serum from mice after single doses of 1e10 to 1e12 virions. B) Tumor growth of 1e6 OVCAR5 cells xenografted into nude mice (N=5) pretreated with 3e11/mouse (1.5e13/kg) LR-MIS or GFP virus (p=0.0003 by two-way ANOVA). Conclusions: AAV9 virally delivered human LR-MIS can produce adequate sustained levels of MIS that inhibited the growth of the human ovarian cancer cell line, OVCAR 5. AAV9 LR MIS provides a well-tolerated, low toxicity treatment of ovarian cancer, which can now be evaluated in a phase 0 trial using PDX models being prepared from human ovarian cancer ascites. Citation Format: David Pepin, Amanda Sosulski, Katherine Hendren, Li Hua Zhang, Fotini Nicolaou, Dan Wang, Guangping Gao, Patricia K Donahoe. An adeno-associated virus (AAV) 9 vector delivering modified human mullerian inhibiting substance (MIS) as a gene therapy for ovarian cancer [abstract]. In: Proceedings of the 10th Biennial Ovarian Cancer Research Symposium; Sep 8-9, 2014; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2015;21(16 Suppl):Abstract nr AS25.

Ferriman-Gallwey Scores, Serum Androgen and Mullerian Inhibiting Substance Levels in Hirstute Adolescent Girls

ObjectiveTo study Ferriman-Gallwey (FG) scoring in adolescents with an aim to correlate these scores with serum androgens and mullerian inhibiting substance (MIS). DesignCross sectional study. SettingPediatric and Adolescent Gynecology Clinic of a university hospital. PatientsTwenty-four hirsute adolescent girls age 12-19 with a FG score of 6 or greater. InterventionsFG examination and collection of serum levels of MIS, total testosterone, free testosterone, follicle stimulating hormone (FSH), luteinizing hormone (LH), prolactin, cortisol, and androstenedione. Main Outcome MeasuresCorrelation between FG scores in adolescents and serum androgens and MIS. ResultsWeak correlations were seen between FG score and FSH, free-testosterone, total testosterone, and cortisol. Increasing FG scores correlated with an increase in cortisol. As FG score increased, FSH, free-testosterone, and total testosterone decreased. There was no statistical relationship between FG score and LH, androstenedione, prolactin, and MIS. There were weak positive correlations between MIS levels and FSH, total testosterone, and androstenedione. There was no evidence for a linear relationship between MIS levels and LH, free testosterone, cortisol, prolactin, and FG score. ConclusionsThe utility of FG scoring in adolescents is unknown. There were no direct correlations found with MIS levels and FG score. MIS was not found to be a predictor of hirsutism. A larger study is needed to assess the clinical relevance of FG scoring and presence of underlying causes of hirsutism in adolescents.

First assessment of menstrual cycle function and reproductive endocrine status in Samoan women

American Samoa and Samoa are now characterized by one of the world's highest levels of adult overweight and obesity. Our objective was to investigate patterns of menstrual cyclicity reported by Samoan women and examine the relationship to adiposity and select hormone levels. A cross-sectional analysis was performed among Samoan women, aged 18-39 years (n = 322), using anthropometric and biomarker measures of adiposity and reproductive health, including insulin, adiponectin, testosterone, sex hormone-binding globulin, free androgen index (FAI) and mullerian-inhibiting substance (MIS). Menstrual regularity was assessed from self-reported responses. Multivariable models were estimated to adjust for potential confounding of the associations between menstrual patterns and other measures. A high proportion of the women (13.7%) reported oligomenorrhea or amenorrhea (OM/AM). More than three-quarters, 80.7%, of women were either overweight or obese, using Polynesian-specific criteria, and OM/AM was significantly associated with higher BMI. Abdominal circumference and insulin levels were significantly higher, and adiponectin levels were lower, in those who reported OM/AM versus regular menstruation. The FAI was higher in women with increased BMI. MIS levels declined with age, more slowly in those reporting OM/AM. Self-reported OM/AM was associated with an elevated BMI, abdominal adiposity and serum insulin, and with reduced adiponectin levels. These findings support a high rate of metabolic syndrome, and perhaps PCOS and reproductive dysfunction, among Samoan women.

Reduced testicular steroidogenesis in tumor necrosis factor-α knockout mice

We previously demonstrated that the expression of Mullerian inhibiting substance (MIS) in Sertoli cells is downregulated by tumor necrosis factor alpha (TNF-α), which is secreted by meiotic germ cells, in mouse testes. Several studies have reported that MIS that is secreted by Sertoli cells inhibits steroidogenesis and, thus, the synthesis of testosterone in testicular Leydig cells. Here, we demonstrate that in TNF-α knockout testes, which show high levels of MIS, steroidogenesis is decreased compared to that in wild-type testes. The levels of testosterone and the mRNA levels of steroidogenesis-related genes were significantly lower after puberty in TNF-α knockout testes than in wild-type testes. Furthermore, the number of sperm was reduced in TNF-α knockout mice. Histological analysis revealed that spermatogenesis is also delayed in TNF-α knockout testes. In conclusion, TNF-α knockout mice show reduced testicular steroidogenesis, which is likely due to the high level of testicular MIS compared to that seen in wild-type mice.

Correlationship of plasminogen activator inhibitor-1 (PAI-1) and mullerian inhibiting substance (MIS) in follicular fluid with endometrial receptivity and pregnancy outcome in ART cycles

OBJECTIVE: Plasminogen activator inhibitor -1 (PAI-1)and Mullerian inhibiting substance (MIS) also known as antimullerian hormone (AMH) in follicular fluid were estimated to evaluate their relationships with endometrial receptivity and pregnancy outcome in ART cycles. DESIGN: Prospective study of 124 IVF cycles. MATERIALS AND METHODS: Controlled ovarian hyperstimulation in all women (Mean age: 30.8 ± 0.4 yrs, BMI: 24.66 ± 0.4) was done with gonadotropin (225 IU / day). Oocyte retrieval was done 34 hours after hCG administration. PAI-1 and MIS concentrations per mg of protein by ELISA and serum E2 and P by RIA method in FF were estimated. Conventional luteal phase support was given in all cycles. Seven days after embryo transfer (ET), serum P, 17OHP and E2 along with transvaginal sonography for endometrial response were measured. Measurement of β hCG on day 14 of ET indicated pregnancy outcome. By the end of sixth week, presence of gestational sac with cardiac activity confirmed clinical pregnancy. Statistical analysis, viz.t test, correlation coefficient and receiver operator characteristics ROC AUC of PAI-1 to determine the cutoff value for achieving pregnancy, was done using Graph pad Prism version 5.0. RESULTS: Out of 124 IVF cycles, six cycles were abandoned due to no response and in eight cycles no ETs were done. A mean of 2.5 ± 0.1 embryos was transferred in 110 IVF cycles. Out of 46 pregnancies (PR: 41.8 %) that resulted, 6 turned out as biochemical pregnancies. The cycles were divided into pregnant and non-pregnant groups. Both FF PAI-1 and FF MIS levels in pregnant group were significantly low (P value: <0.0001) as compared to non-pregnant group. FF MIS strongly correlated with FF PAI-1 and D7 OHP in pregnant group (Pearson r: 0.4515 and 0.3321 respectively). Serum17- OHP levels and endometrial thickness on D7 in non-pregnant group showed inverse correlation with FF PAI-1 (Pearson r = - o.3324). Though sr. P in both groups remained almost unchanged, 17- OHP and E2 levels were found to be significantly high (0.05 and 0.005 respectively) in pregnant group as compared to non-pregnant group on D7 of ET. CONCLUSIONS: MIS seemed to regulate the activity of PAI-1 in ART cycles. Lower PAI-1 activity in follicular fluid seemed to denote the promotion or triggering factor for increased proteolytic activity at the endometrial level to prepare a favorable bed for invasion of trophoblasts of the embryo, which facilitated its implantation.

The relationship of bariatric surgery to Mullerian Inhibiting Substance

Mullerian Inhibiting Substance (MIS) is emerging as a predictor of ovarian reserve, and the frequency of bariatric surgical procedures have increased dramatically in reproductive aged women. The purpose of this study is to assess changes in plasma MIS after “dramatic” weight loss by bariatric surgery in morbidly obese reproductive aged women. A prospective study. Sixteen patients, who underwent bariatric surgery, were enrolled in a prospective study evaluating MIS levels preoperatively and postoperatively. Since women aged less than 35 have the most reproductive potential and since women aged more than 35 and post-menopausal women have minimally detectable MIS, we have divided the participants into three groups. Group 1 included patients aged less than 35, group 2 included women aged more than 35 but not menopausal, and group 3 contained postmenopausal women. At the time of MIS sampling, a questionnaire was completed. Postoperative samples were taken between 43 and 151 days (mean ± SD = 87 ± 30) after the surgery. The blood was centrifuged and the plasma was stored at −80°C until assayed. The study was approved by the IRB of Maimonides Medical Center, and participants signed an informed consent. Seven participants were under 35 years old, four were above 35 years old and five were post-menopausal. Table 1 summarizes the demographic data and the clinical profile of the participants. MIS concentrations showed a 23.9% decrease (P=0.034) in group 1 while BMI decreased by 14.5%. TableDemographics and clinical profileGroup 1 (N = 7)Group 2 (N = 4)Group 3 (N = 5)Age (years) [mean (± SD)]29.6 (2.82)40.5 (4.8)51.2 (6.46)Ethnicity White443 Hispanic301 Black001 Other000Irregular menses Yes11NA No63NAHistory of infertility Yes200 No545History of PCOS Yes110 No635Parity 0100 1–2223 >2422BMI Preoperative BMI (kg/m2) [mean (± SD)]50.3 (9.79)44.4 (6.77)48.7 (9.42) Postoperative BMI (kg/m2) [mean (± SD)]43.0 (10.943)35.8 (2.762)42.9 (6.803)MIS MIS preoperatively (ng/mL) (mean)3.8.63.10 MIS postoperatively (ng/mL) (mean)2.89 (P=0.034).80.10NA = Not Applicable. Open table in a new tab NA = Not Applicable. Preliminary data suggests that surgical weight loss among women under 35 is associated with a decrease in plasma MIS. These findings may contribute to a greater understanding of the complex relationship between obesity and female reproduction.

Mullerian inhibiting substance (MIS) reflects ovarian and biochemical aberrations in polycystic ovary syndrome (PCOS) better than Inhibin B

MIS, also known as anti-Mullerian hormone (AMH), a member of the TGFβ superfamily, is a product of granulosa cells and is expressed in females postnatally. Recently, data have suggested that MIS may reflect the size of the antral follicle pool, and therefore may be a useful marker of ovarian aging. Also, a few reports have suggested that MIS levels are higher in women with PCOS, but there is incomplete information regarding elevations when compared to age and weight matched controls, as well as relationships to ovarian morphology, levels of inhibin B (another putative marker of antral follicle health), and other reproductive hormones. Prospective observational trial in PCOS and matched controls. Fifty women with PCOS were recruited based on the classic criteria of chronic anovulation and hyperandrogenism. These women (age 25.8 ± 0.5 yrs; BMI 29.1 ± 0.9) were compared to 34 age (25.4 ± 0.8 yrs) and BMI (27.5 ± 0.6) matched ovulatory controls. Fasting blood was obtained in all subjects in the early follicular phase (days 5–6) after spontaneous or induced menses (in PCOS), as was vaginal ultrasound for assessments of ovarian volume and blood flow. Women with PCOS had higher LH (14.0 ± 0.9 vs. 9.1 ± 0.3 mIU/ml), testosterone (T, 103±7 vs. 43±3 ng/dl), and androstenedione (A, 3.6 ± 0.2 vs. 1.6 ± 0.1 ng/ml), as well as higher insulin (19.5 ± 1.2 vs. 7.3 ± 0.5 μU/ml) and lower QUICKI (0.31 ± 0.003 vs. 0.37 ± 0.003), p < 0.01. Ovarian volume was higher in PCOS (12.0 ± 0.9 vs. 4.7 ± 0.2 cc), and the pulsatility index was lower (1.4 ± 0.05 vs. 2.5 ± 0.1), p < 0.01. Inhibin B concentrations were higher in PCOS (70 ± 8.0 vs. 40 ± 3.4 pg/ml), as were MIS levels (6.7 ± 0.9 vs. 4.6 ± 0.5 ng/ml), p < 0.05. While inhibin B correlated directly with levels of MIS (r = 0.351, p < 0.01), inhibin B did not correlate with ovarian size or reproductive hormones, insulin or QUICKI. However, MIS correlated positively with ovarian size (r = 0.350, p < 0.05), LH (r = 0.312, p < 0.01), T (r = 0.280, p < 0.05), A (r = 0.389, p < 0.01), and estradiol (r = 0.281, p < 0.05), but MIS did not correlate with ovarian blood flow. In addition, MIS correlated positively with insulin (r = 0.249, p < 0.05) but not with BMI. Women with PCOS with the highest levels of MIS had higher ovarian volumes and values of LH, T, A, and insulin. These data suggest that MIS may be an important biochemical marker in PCOS and elevated levels may relate to the pathophysiology of the ovarian dysfunction.

Effects of Mono-(2-Ethylhexyl) Phthalate on Fetal and Neonatal Rat Testis Organ Cultures1

Di-(2-ethylhexyl) phthalate (DEHP) and its active metabolite, mono-(2-ethylhexyl) phthalate (MEHP), have been shown to cause reproductive toxicity in both developing and adult animals. In this study, we used organ cultures of fetal and neonatal rat testes to assess the in vitro effect of MEHP on seminiferous cord formation in Embryonic Day 13 (E13) testes and on the development of E18 and Postnatal Day 3 (P3) testes. Interestingly, MEHP had no effect on cord formation in the organ cultures of E13 testes, indicating that it has no effect on sexual differentiation of the indifferent gonad to testis. Consistently, the expression of a Sertoli cell-specific protein, mullerian inhibiting substance (MIS), or the number of gonocytes did not change in E13 testes after MEHP treatment. In contrast, MEHP decreased the levels of MIS and GATA-4 proteins in Sertoli cells and impaired Sertoli cell proliferation in the organ cultures of E18 and P3 testes. These results suggest that MEHP negatively influences proliferation and differentiation of Sertoli cells in both fetal and neonatal testes. In addition, MEHP treatment did not alter the number of gonocytes in E18 testes, whereas the number of gonocytes in P3 testes decreased in a dose-dependent manner, apparently due to enhanced apoptosis. These results suggest that MEHP adversely affects the gonocytes, which are mitotically active and undergoing migration and differentiation in neonatal testes, but it has no effect on fetal gonocytes that are mitotically quiescent.

Expression levels of Mullerian-inhibiting substance, GATA4 and 17alpha-hydroxylase/17,20-lyase cytochrome P450 during embryonic gonadal development in two diverse breeds of swine.

Sexual differentiation and early embryonic/fetal gonad development is a tightly regulated process controlled by numerous endocrine and molecular signals. These signals ensure appropriate structural organization and subsequent development of gonads and accessory organs. Substantial differences exist in adult reproductive characteristics in Meishan (MS) and White Composite (WC) pig breeds. This study compared the timing of embryonic sexual differentiation in MS and WC pigs. Embryos/fetuses were evaluated on 26, 28, 30, 35, 40 and 50 days postcoitum (dpc). Gonadal differentiation was based on morphological criteria and on localization of GATA4, Mullerian-inhibiting substance (MIS) and 17alpha-hydroxylase/17,20-lyase cytochrome P450 (P450(c17)). The timing of testicular cord formation and functional differentiation of Sertoli and Leydig cells were similar between breeds. Levels of GATA4, MIS and P450(c17) proteins increased with advancing gestation, with greater levels of MIS and P450(c17) in testes of MS compared with WC embryos. Organization of ovarian medullary cords and formation of egg nests was evident at similar ages in both breeds; however, a greater number of MS compared with WC embryos exhibited signs of ovarian differentiation at 30 dpc. In summary, despite breed differences in MIS and P450(c17) levels in the testis, which may be related to Sertoli and Leydig cell function, the timing of testicular differentiation did not differ between breeds and is unlikely to impact reproductive performance in adult boars. In contrast, female MS embryos exhibited advanced ovarian differentiation compared with WC embryos which may be related to the earlier reproductive maturity observed in this breed.

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.

Mullerian inhibiting substance in humans: normal levels from infancy to adulthood.

Mullerian-inhibiting substance (MIS) is a gonadal hormone synthesized by Sertoli cells of the testis and granulosa cells of the ovary. To facilitate the use of MIS for the evaluation of intersex disorders and as a tumor marker in women with MIS-expressing ovarian tumors, we measured MIS in 600 serum samples from males and females. These data show that mean MIS values for males rise rapidly during the first year of life and are highest during late infancy, then gradually decline until puberty. In contrast, MIS values in females are lowest at birth and exhibit a minimal increase throughout the prepubertal years. Whereas MIS is uniformly measurable in all prepubertal boys studied, it is undetectable in most prepubertal female subjects. These data reveal an easily discernible sexually dimorphic pattern of expression and confirm that MIS can be used as a testis-specific marker during infancy and early childhood. MIS values that are above the upper limits for females are discriminatory for the presence of testicular tissue or ovarian tumor, and those below the lower limits for males are consistent with dysgenetic or absent testes or the presence of ovarian tissue. These data will enable normal and abnormal levels of MIS to be differentiated with higher precision and will facilitate the use of MIS in the management of gonadal disorders.

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

Serum levels of mullerian inhibiting substance in boys throughout puberty and in the first two years of life.

Serum levels of Mullerian inhibiting substance (MIS) have been measured in 91 boys throughout normal pubertal development. MIS levels fell sharply after pubertal stage 1 and were mostly undetectable at pubertal stage 6. The relationship between MIS concentration and pubertal stage was similar when compared with age. Seven patients with precocious puberty and 12 with delayed puberty were also investigated and found to have MIS levels consistent with their degree of pubertal development. Precocious puberty was associated with MIS levels that were abnormally low for age, while delayed puberty resulted in persistence of high MIS levels. Serum MIS levels were also measured in 29 boys less than 2 yr of age undergoing minor surgery. High levels were found throughout this time period, which is consistent with previous reports. MIS levels appear to be inversely related to levels of gonadotropins, steroids, and inhibin, which fall in the first 2 yr of life and rise throughout puberty.

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.

Serum levels of mullerian inhibiting substance in boys with cryptorchidism

Serum levels of Mullerian inhibiting substance (MIS) were measured in boys with cryptorchidism (n = 104) and paired, age-matched controls (n = 104) using an enzyme immunoassay. Control MIS levels were high during the first year of life with a peak level at 4 to 12 months, subsequently diminishing with age. MIS levels in patients with undescended testes also declined with age, although a surge was not found in the first year. Mean MIS concentration of cryptorchid boys was significantly lower than controls ( P < .001). There was a significantly reduction of the mean MIS level in children with bilateral cryptorchidism compared with those with unilateral undescended testis ( P < .05). These differences might support the hypothesis that MIS initiates transabdominal testicular descent. However, because most undescended testes are probably the result of anatomical or functional abnormalities during transinguinal testicular descent, differences in MIS levels more likely result from secondary testicular degeneration. In the future, MIS immunoassay should play an important role in the investigation of gonadal function in boys with various genital disorders, including cryptorchidism.

Mullerian Inhibiting Substance Ontogeny and its Modulation by Follicle-Stimulating Hormone in the Rat Testes*

Mullerian Inhibiting Substance (MIS) production in rat testes from the late fetal to the adult period and its modulation by gonadotropins in neonatal testes were studied using immunohistochemistry, northern analysis, and a graded organ culture bioassay for MIS. The intense immunohistochemical staining for MIS seen in fetal and newborn testes began to decrease gradually after the third postnatal day, then decreased dramatically on the fifth postnatal day. MIS immunohistochemical activity was then present at a low level until about the 20th postnatal day, after which it was barely detectable. The testes from rats treated with FSH at birth showed a considerable drop in MIS immunohistochemical activity on the third postnatal day to 29% of control testes, and a less profound decrease on the second and fourth postnatal days to 46% and 61% of control, respectively; thereafter MIS levels were the same in treated and untreated animals. With shorter courses of FSH treatment, immunohistochemical staining showed less depression of MIS on the third day, and no difference by the fourth postnatal day, indicating that the inhibitory effect on testicular MIS production may require continued FSH exposure. Three-day testes that had been treated with FSH for 2-1/2 days had less MIS messenger RNA compared to control testes of the same age, suggesting that the inhibitory effect of FSH on MIS production could be transcriptionally mediated. In contrast LH treatment produced no difference in either messenger RNA expression or immunohistochemical staining for MIS. These findings suggested that FSH may be a modulator of MIS production in neonatal testes.

The ontogeny of mullerian inhibiting substance in the gonads of the chicken

Mullerian inhibiting substance (MIS) was studied in the testis, ovary, and ovotestis of the domestic fowl, from early embryonic development to adulthood by a graded organ-culture method using the urogenital ridge of a 14.5 day fetal rat. The chick testis had high levels of MIS from 8 days of embryonic development (4-5+) until sexual maturity, when activity declined (2+) but persisted throughout adulthood. The right gonad (ovotestis) of the hen showed moderate levels of MIS activity from 8 to 12 days of embryonic life (1-3+) before its normal involution by the time of hatching (21 days). The left gonad (ovary) of the hen also produced MIS at levels similar to that seen in the testis. Activity was high during embryonic development (4+) and after hatching, and persisted in the adult hen at diminished levels (2+). MIS production by the female gonads explains regression of the right Mullerian duct, but the mechanisms that allow preservation of the left duct remain unexplained. Evidence suggests that ovarian estrogens may interact with MIS at the receptor level to protect the left Mullerian duct. MIS persists in the sexually mature gonads of both the hen and cockeral, long after the Mullerian duct has regressed, suggesting a wider role for this substance in reproductive physiology.