Serum inhibin B levels in males with gonadal dysfunction

The Molecular Basis of Male Infertility in Obesity: A Literature Review

The rising incidence of obesity has coincided with rising levels of poor reproductive outcomes. The molecular basis for the association of infertility in obese males is now being explained through various mechanisms. Insulin resistance, hyperglycemia, and changes in serum and gonadal concentrations of adipokines, like leptin, adiponectin, resistin, and ghrelin have been implicated as causes of male infertility in obese males. The effects of obesity and hypogonadism form a vicious cycle whereby dysregulation of the hypothalamic-pituitary-testicular axis-due to the effect of the release of multiple mediators, thus decreasing GnRH release from the hypothalamus-causes decreases in LH and FSH levels. This leads to lower levels of testosterone, which further increases adiposity because of increased lipogenesis. Cytokines such as TNF-α and interleukins, sirtuins, and other inflammatory mediators like reactive oxygen species are known to affect fertility in obese male adults. There is evidence that parental obesity can be transferred through subsequent generations to offspring through epigenetic marks. Thus, negative expressions like obesity and infertility have been linked to epigenetic marks being altered in previous generations. The interesting aspect is that these epigenetic expressions can be reverted by removing the triggering factors. These positive modifications are also transmitted to subsequent generations.

Hypogonadism induced by surgical stress and brain trauma is reversed by human chorionic gonadotropin in male rats: A potential therapy for surgical and TBI-induced hypogonadism?

INTRODUCTION

Hypogonadotropic hypogonadism (HH) is an almost universal, yet underappreciated, endocrinological complication of traumatic brain injury (TBI). The goal of this study was to determine whether the developmental hormone human chorionic gonadotropin (hCG) treatment could reverse HH induced by a TBI.

METHODS

Plasma samples were collected at post-surgery/post-injury (PSD/PID) days -10, 1, 11, 19 and 29 from male Sprague-Dawley rats (5- to 6-month-old) that had undergone a Sham surgery (craniectomy alone) or CCI injury (craniectomy + bilateral moderate-to-severe CCI injury) and treatment with saline or hCG (400 IU/kg; i.m.) every other day.

RESULTS

Both Sham and CCI injury significantly decreased circulating testosterone (T), 11-deoxycorticosterone (11-DOC) and corticosterone concentrations to a similar extent (79.1% vs. 80.0%; 46.6% vs. 48.4%; 56.2% vs. 32.5%; respectively) by PSD/PID 1. hCG treatment  returned circulating T to baseline concentrations by PSD/PID 1 (8.9 ± 1.5 ng/ml and 8.3 ± 1.9 ng/ml; respectively) and was maintained through PSD/PID 29. hCG treatment significantly, but transiently, increased circulating progesterone (P4) ~3-fold (30.2 ± 10.5 ng/ml and 24.2 ± 5.8 ng/ml) above that of baseline concentrations on PSD 1 and PID 1, respectively. hCG treatment did not reverse hypoadrenalism following either procedure.

CONCLUSIONS

Together, these data indicate that (1) craniectomy is sufficient to induce persistent hypogonadism and hypoadrenalism, (2) hCG can reverse hypogonadism induced by a craniectomy or craniectomy +CCI injury, suggesting that (3) craniectomy and CCI injury induce a persistent hypogonadism by decreasing hypothalamic and/or pituitary function rather than testicular function in male rats. The potential role of hCG as a cheap, safe and readily available treatment for reversing surgery or TBI-induced hypogonadism is discussed.

Can preoperative parameters predict successful sperm retrieval and live birth in couples undergoing testicular sperm extraction and intracytoplasmic sperm injection for azoospermia?

Background

We aimed to determine if the success of TESE and live-birth following TESE-ICSI can be predicted from readily available preoperative parameters for couples with azoospermia. Our methodology was as follows, this was a cohort study of couples who attended the fertility service (from 2009-2019) at an NHS hospital in whom the male partner was diagnosed with azoospermia and required conventional TESE with multiple biopsies to obtain sperm. Of 414 men included, 223 had successful TESE and of those 178 have used sperm in ICSI cycle(s). Predictive models were developed using logistic regression. We assessed model performance by internally validated concordance statistics and calibration plots. Successful sperm retrieval was defined as the presence of motile sperm which survived the freeze-thaw process and live-birth defined as delivery after 34 weeks of gestation.

Results

Successful TESE was associated with higher male age and lower FSH. The TESE model discriminated well with a c statistic of 0.81 (0.77-0.85). Live-birth was associated with lower maternal age, earlier ICSI cycle, and lower testicular volume. The live-birth model also discriminated well with a c statistic of 0.70 (0.64-0.76).

Conclusions

These results support the pragmatic counselling of couples diagnosed with azoospermia about the chances of success of the TESE procedure and of biological parenthood prior to surgical intervention. The models help to discriminate between men who have a high or low chance of successful TESE and couples who have a higher chance of achieving a live-birth after successful TESE. This will allow couples to make a better assessment of the balance of risk versus benefit prior to commitment to surgical interventions.

Association of polymorphism c.-124G>A and c.-16 C>T in the promoter region of human INHA gene with altered sperm parameters; A pilot study

OBJECTIVE

The objective of this was to demonstrate the association of Inhibin α (INHα) c.-124G>A and INHα-c.-16 C>T polymorphisms with altered sperm parameters in a selected male population of Karachi, Pakistan.

STUDY DESIGN & SETTINGS

In this pilot study, male subjects were stratified on the basis of the WHO criteria for altered sperm parameters; 83 (cases-altered sperm parameters) and 30 (controls-normal sperm parameters) subjects were included for analysis of INHα-c.124G>A polymorphism and 88 (cases) and 38 (controls) were analysed for INHα -c-16 C>T polymorphism. Genotyping of INHα-c.-124G>A and INHα-c.-16 C>T was performed by PCR-RFLP, genotype distribution in Hardy-Weinberg equilibrium was evaluated by binary logistic regression model.

RESULTS

For the c.-124G>A polymorphism in INHα gene, frequency of the three major genotypes in controls was: GG: 80.0%, GA: 20.0% and AA: 0% and in cases was: GG: 59.0%, GA: 30.2% and AA: 10.8%. The GG genotype was significantly associated with male infertility (P < .045, OR = 2.776, 95% CI = 1.025-7.513) while the GA genotype was not significantly associated with infertility (P < .290 OR = 0.580, 95% CI = 0.211-1.593). Frequency of mutant AA genotype was 10.8% in cases (altered sperm parameters) and absent (0%) in normal sperm parameter (controls). The frequencies of three major genotypes CC, CT and TT did not show any significant difference between cases and controls (P > .05).

CONCLUSION

The results from our study exhibited a significant association of c.-124G>A polymorphism in the INHα gene promoter region with male infertility in the Pakistani population. A significant association of c.-16 C>T polymorphism with male infertility, however, was not observed. Further large-scale studies should be conducted to confirm this association.

Prediction of sperm extraction in non-obstructive azoospermia patients: a machine-learning perspective

STUDY QUESTION

Can a machine-learning-based model trained in clinical and biological variables support the prediction of the presence or absence of sperm in testicular biopsy in non-obstructive azoospermia (NOA) patients?

SUMMARY ANSWER

Our machine-learning model was able to accurately predict (AUC of 0.8) the presence or absence of spermatozoa in patients with NOA.

WHAT IS KNOWN ALREADY

Patients with NOA can conceive with their own biological gametes using ICSI in combination with successful testicular sperm extraction (TESE). Testicular sperm retrieval is successful in up to 50% of men with NOA. However, to the best of our knowledge, there is no existing model that can accurately predict the success of sperm retrieval in TESE. Moreover, machine-learning has never been used for this purpose.

STUDY DESIGN, SIZE, DURATION

A retrospective cohort study of 119 patients who underwent TESE in a single IVF unit between 1995 and 2017 was conducted. All patients with NOA who underwent TESE during their fertility treatments were included. The development of gradient-boosted trees (GBTs) aimed to predict the presence or absence of spermatozoa in patients with NOA. The accuracy of these GBTs was then compared to a similar multivariate logistic regression model (MvLRM).

PARTICIPANTS/MATERIALS, SETTING, METHODS

We employed univariate and multivariate binary logistic regression models to predict the probability of successful TESE using a dataset from a retrospective cohort. In addition, we examined various ensemble machine-learning models (GBT and random forest) and evaluated their predictive performance using the leave-one-out cross-validation procedure. A cutoff value for successful/unsuccessful TESE was calculated with receiver operating characteristic (ROC) curve analysis.

MAIN RESULTS AND THE ROLE OF CHANCE

ROC analysis resulted in an AUC of 0.807 ± 0.032 (95% CI 0.743–0.871) for the proposed GBTs and 0.75 ± 0.052 (95% CI 0.65–0.85) for the MvLRM for the prediction of presence or absence of spermatozoa in patients with NOA. The GBT approach and the MvLRM yielded a sensitivity of 91% vs. 97%, respectively, but the GBT approach has a specificity of 51% compared with 25% for the MvLRM. A total of 78 (65.3%) men with NOA experienced successful TESE. FSH, LH, testosterone, semen volume, age, BMI, ethnicity and testicular size on clinical evaluation were included in these models.

LIMITATIONS, REASONS FOR CAUTION

This study is a retrospective cohort study, with all the associated inherent biases of such studies. This model was used only for TESE, since micro-TESE is not performed at our center.

WIDER IMPLICATIONS OF THE FINDINGS

Machine-learning models may lay the foundation for a decision support system for clinicians together with their NOA patients concerning TESE. The findings of this study should be confirmed with further larger and prospective studies.

STUDY FUNDING/COMPETING INTEREST(S)

The study was funded by the Division of Obstetrics and Gynecology, Soroka University Medical Center, there are no potential conflicts of interest for all authors.

Primary gonadal failure

The term primary gonadal failure encompasses not only testicular insufficiency in 46,XY males and ovarian insufficiency in 46,XX females, but also those disorders of sex development (DSD) which result in gender assignment that is at variance with the genotype and gonadal type. In boys, causes of gonadal failure include Klinefelter and other aneuploidy syndromes, bilateral cryptorchidism, testicular torsion, and forms of 46,XY DSD such as partial androgen insensitivity. Causes in girls include Turner syndrome and other aneuploidies, galactosemia, and autoimmune ovarian failure. Iatrogenic causes in both boys and girls include the late effects of childhood cancer treatment, total body irradiation prior to bone marrow transplantation, and iron overload in transfusion-dependent thalassaemia. In this paper, a brief description of the physiology of testicular and ovarian development is followed by a section on the causes and practical management of gonadal impairment in boys and girls. Protocols for pubertal induction and post-pubertal hormone replacement - intramuscular, oral and transdermal testosterone in boys; oral and transdermal oestrogen in girls - are then given. Finally, current and future strategies for assisted conception and fertility preservation are discussed.

Predictivity of Nonclinical Male Reproductive Findings for Human Effects

BACKGROUND

Testing of pharmaceutical products for reproductive toxicity in male laboratory animals is required for registration.

METHODS

We evaluated whether the results of studies showing male reproductive toxicity in experimental animals was predictive of reproductive effects in men participating in clinical trials. We surveyed companies for information on pharmaceutical candidates that had shown male reproductive toxicity in nonclinical studies for which there was information on male reproductive effects in clinical trials.

RESULTS

Among 12 pharmaceutical candidates submitted by five companies, only one compound that had shown male reproductive toxicity in experimental animals also demonstrated reproductive toxicity in men.

CONCLUSION

In this sample of compounds, nonclinical studies appeared to over-predict reproductive toxicity in men. We identified possible reasons for the apparent lack of predictivity of the experimental animal studies. Birth Defects Research 110:17-26, 2018. © 2017 Wiley Periodicals, Inc.

Do body mass index, hormone profile and testicular volume effect sperm retrieval rates of microsurgical sperm extraction in the patients with nonobstructive azoospermia?

OBJECTIVE

We aimed to evaluate the effect of body mass index (BMI), follicle stimulating hormone (FSH), and luteinizing hormone (LH) levels and the mean testicular volume on sperm retrieval rates in microsurgical sperm extraction (microTESE) in the patients with nonobstructive azoospermia (NOA).

MATERIAL AND METHODS

The data of 282 infertile patients with NOA were analysed retrospectively. The patients with normal karyotype and no Y microdeletions were included in the study. The patients were classified according to their BMI scores and the medical history, physical examination and hormonal parameters were evaluated. The overall data were processed statistically with chi-square and logistic regression analysis and the relation between preoperative findings and sperm retrieval rates was investigated.

RESULTS

The sperm retrieval rate of 282 patients after microTESE was found as 41.1%. There was no statistically significant difference in sperm retrieval rates among the subgroups classified according to BMI. FSH and LH levels and the mean testicular volume and pathologic findings were significantly correlated with sperm retrieval rates.

CONCLUSION

Finally significant correlation was determined between sperm retrieval rates and FSH, and LH levels and testicular volumes but no statistically significant difference was found in sperm retrieval rates among BMI groups.

Biological markers of fertility (inhibin-B) in HIV-infected men: influence of HIV infection and antiretroviral therapy

OBJECTIVES

Inhibin B (IB) levels and the IB: follicle-stimulating hormone (FSH) ratio (IFR), biomarkers of global Sertoli cell function, show a strong relationship with male fertility. The aim of the study was to examine the prevalence of impaired fertility potential in HIV-infected men and the influence of antiretroviral therapy (ART) on fertility biomarkers.

METHODS

A cross-sectional study with sequential sampling was carried out. A total of 169 clinically stable patients in a cohort of HIV-infected men undergoing regular ambulatory assessment in a tertiary hospital were included. The mean [± standard deviation (SD)] age of the patients was 42.6 ± 8.1 years, all were clinically stable, 61.5% had disease classified as Centers for Disease Control and Prevention (CDC) stage A, and were na?ve to ART or had not had any changes to ART for 6 months (91.1%). Morning baseline IB and FSH concentrations were measured using an enzyme-linked immunosorbent assay (ELISA) and an electrochemiluminescent immunoassay (ECLIA), respectively. A multivariate logistic regression model was used to identify factors associated with impaired fertility, defined as IB < 119 pg/mL or IFR < 23.5.

RESULTS

The mean (± SD) IB level was 250 ± 103 pg/mL, the median [interquartile range (IQR)] FSH concentration was 5.1 (3.3-7.8) UI/L and the median (IQR) IFR was 46.1 (26.3-83.7). The prevalence of impaired fertility was 21.9% [95% confidence interval (CI) 16.3-20.7%]. Negative correlations of body mass index and waist: hip ratio with FSH and IB levels were observed (P < 0.01), while a sedentary lifestyle and previous nevirapine exposure were associated with a decreased risk of IB levels ≤ 25th percentile in multivariate analysis. Only older age, as a risk factor, and sedentary lifestyle, with a protective effect, were independently associated with impaired fertility in multivariate analysis.

CONCLUSIONS

Global testicular Sertoli cell function and fertility potential, assessed indirectly through serum IB levels and IB: FSH ratio, appear to be well maintained in HIV-infected men and not damaged by ART.

Inhibin at 90: from discovery to clinical application, a historical review

When it was initially discovered in 1923, inhibin was characterized as a hypophysiotropic hormone that acts on pituitary cells to regulate pituitary hormone secretion. Ninety years later, what we know about inhibin stretches far beyond its well-established capacity to inhibit activin signaling and suppress pituitary FSH production. Inhibin is one of the major reproductive hormones involved in the regulation of folliculogenesis and steroidogenesis. Although the physiological role of inhibin as an activin antagonist in other organ systems is not as well defined as it is in the pituitary-gonadal axis, inhibin also modulates biological processes in other organs through paracrine, autocrine, and/or endocrine mechanisms. Inhibin and components of its signaling pathway are expressed in many organs. Diagnostically, inhibin is used for prenatal screening of Down syndrome as part of the quadruple test and as a biochemical marker in the assessment of ovarian reserve. In this review, we provide a comprehensive summary of our current understanding of the biological role of inhibin, its relationship with activin, its signaling mechanisms, and its potential value as a diagnostic marker for reproductive function and pregnancy-associated conditions.

Summary of the HESI consortium studies exploring circulating inhibin B as a potential biomarker of testis damage in the rat

The Developmental and Reproductive Toxicity Technical Committee of the Health and Environmental Sciences Institute hosted a working consortium of companies to evaluate a new commercially available analytic assay for Inhibin B in rat serum or plasma. After demonstrating that the kit was stable and robust, the group performed a series of independent pathogenesis studies (23 different compound/investigator combinations) designed to examine the correlation between the appearance of lesions in the testis and changes in circulating levels of Inhibin B. These studies were reported individually in the previous articles in this series (this issue), and are discussed in this paper. For roughly half of these exposures, lesions appeared well before Inhibin B changed. A few of the studies showed a good correlation between seminiferous tubule damage and reduced circulating Inhibin B levels, while for seven exposures, circulating Inhibin B was reduced with no detectable alteration in testis histology. Whether this indicates a prodromal response or a false-positive signal will require further investigation. These exceptions could plausibly suggest some value of circulating Inhibin B as a useful biomarker in some circumstances. However, for roughly half of these exposures, Inhibin B appeared to be a lagging biomarker, requiring significant damage to the seminiferous tubules before a consistent and credible reduction in circulating levels of Inhibin B was observed.

Effect of risperidone and olanzapine on reproductive hormones, psychopathology and sexual functioning in male patients with schizophrenia

OBJECTIVE

To study the effect of drugs on the hypothalamo-pituitary-gonadal (HPG) axis we compared the endocrine actions of two neuroleptics with different receptor affinity profiles-risperidone and olanzapine in male schizophrenic patients.

METHODS

We investigated the levels of prolactin, estradiol, testosterone, LH, FSH and testicular peptide hormone-inhibin B, and we assessed psychopathology (PANSS), sexual function (ASEX) and treatment adherence (DAI-10) in 89 male schizophrenic inpatients treated with olanzapine or risperidone administered orally. The initial and final evaluations were carried out at weeks 3 and 8 after the onset of treatment, respectively.

RESULTS

At initial evaluation the mean serum prolactin and inhibin B levels were markedly higher, whereas testosterone level was lower in patients treated with risperidone, than in those treated with olanzapine. In 5 out of 50 subjects from risperidone group (10%) and in 1 from olanzapine group (2.6%) testosterone levels were below the lower limit (<241ng/ml), which reflected Leydig's cell impairment. In one patient receiving risperidone and in three receiving olanzapine, inhibin B level was below 80pg/ml, indicating Sertoli's cell dysfunction. At the final evaluation the mean serum prolactin level was markedly higher in patients taking risperidone, whereas their FSH levels were lower than in patients receiving olanzapine. In all investigated groups, except for the risperidone-hyperprolactinemic group inhibin B levels were negatively correlated with serum FSH. The mean LH, FSH, testosterone and estradiol levels were within the normal reference range at initial and final evaluation. The non-adherence to medications and ASEX scores were significantly higher in risperidone groups. Sexual dysfunction and medication non-adherence was not related to prolactin or gonadal hormone levels.

CONCLUSIONS

Risperidone elicited higher PRL elevation than olanzapine. Treatment with this medication can be associated with disturbances in reproductive hormones (testosterone) and gonadotropins (FSH). The cause of olanzapine-elicited reduction of inhibin B level and the lack of negative correlation between FSH and inhibin B in patients with risperidone-induced hyperprolactinemia require further investigation. Patients receiving risperidone showed higher level of sexual dysfunction and treatment non-adherence than those treated with olanzapine.

Can serum Inhibin B and FSH levels, testicular histology and volume predict the outcome of testicular sperm extraction in patients with non-obstructive azoospermia?

INTRODUCTION

In our study, we evaluated the diagnostic accuracy of serum follicle stimulating hormone (FSH), Inhibin B, testicular volumes and distribution of testicular sperm extraction (TESE) outcome according to the histological diagnosis in men with non-obstructive azoospermia.

MATERIALS AND METHODS

Between February 2001 and April 2002, 66 men presenting with infertility of at least 1 year were found to have non-obstructive azoospermia. Serum FSH and Inhibin B levels, testicular volumes and pathological analysis were reviewed retrospectively using medical records of these patients.

RESULTS

Of 66 patients, 52 were enrolled into the study and sperm extraction was successful in 31 of 52 patients (59.6%). There was no statistically significant difference between the patients who had successful and unsuccessful TESE in terms of mean serum Inhibin B, FSH levels and testicular volumes (P>0.05). The area under ROC analysis for serum Inhibin, serum FSH and testicular volume was 0.557, 0.523 and 0.479, respectively. For Inhibin B, the best cut-off value for discriminating between successful and failed TESE at 90% sensitivity was 6.25 with a very low level of specificity (14%) and diagnostic accuracy that was 53.8.

CONCLUSION

Besides the controversies about the direct marker role of serum Inhibin B in determination of spermatogenesis, it does not seem to give a clue about the prediction of sperm presence before TESE. Because of the conflicting results in the literature, the potential role of serum Inhibin B as a marker for prediction of sperm presence in testis is yet to be determined.

Inhibin B is a better marker of spermatogenesis than other hormones in the evaluation of male factor infertility

OBJECTIVE

To assess the role of inhibin B in the evaluation of male factor infertility.

DESIGN

Prospective study.

SETTING

Reproductive endocrinology clinic.

PATIENT(S)

Seventy-five patients with infertility problems (mean age 31.2 +/- 7.5 years) and 12 controls (32.1 +/- 8.8 years) with proven fertility.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Semen analysis was performed according to World Health Organization guidelines. Testicular volume was assessed with the Prader's orchidometer. Serum levels of inhibin B (pg/mL), LH (mIU/mL), FSH (mIU/mL), prolactin (micro IU/mL), and testosterone (nmol/L) were assessed.

RESULT(S)

The mean +/- SEM inhibin B and testosterone levels were significantly lower in the patients than in the controls (inhibin B: 116.4 +/- 11.7 vs. 181.2 +/- 20.9, P=.008; testosterone: 13.6 +/- 0.9 vs. 25.1 +/- 2.9, P=.008). In general, sperm count and testicular volume in the patients were significantly and positively correlated with inhibin B (sperm count: r = 0.476, P<.0001; testicular volume, right: r = 0.57, P=.0001; left: r = 0.53, P=.0001); the inhibin B-FSH index was negatively correlated with FSH. Inhibin B was more strongly correlated with testicular volume and semen parameters than FSH. Inhibin B in the patients was negatively correlated with FSH (r = -0.723, P=.0001) and LH (r = -0.52, P=.0001) and was positively correlated with testosterone (r = 0.4, P=.0013).

CONCLUSION(S)

Inhibin B measurement is a better marker of fertility status than FSH and LH. Concentration of inhibin B in patients with infertility may provide useful information on spermatogenesis and possibly serve as a more direct marker of spermatogenesis than FSH.

Fecundability according to male serum inhibin B—a prospective study among first pregnancy planners

BACKGROUND

New biological markers of male fecundity are needed for use in large-scale epidemiological studies. We studied the association between male inhibin B and fecundability.

METHODS

Four hundred and thirty Danish couples without previous reproductive experience were followed from termination of contraception until pregnancy or for a maximum of six menstrual cycles. At enrolment we obtained semen samples (n = 418) and blood samples to measure reproductive hormones, including inhibin B (n = 343).

RESULTS

The fecundability odds ratio for an increment of male inhibin B by 1 log pg/ml was 1.428 (95% confidence interval 1.022-1.994), adjusted for factors influencing the crude estimate. Only inhibin B values below 100 pg/ml were strongly related to fecundability. We designed a receiver operating characteristic curve based on the 29 males with serum inhibin B #100 pg/ml. The area under the curve (AUC) for inhibin B was 0.787 and the corresponding AUCs for sperm density and FSH were 0.913 and 0.800, respectively.

CONCLUSION

Serum inhibin B may be a reliable marker of male fecundity for epidemiological research and may have some advantages over sperm density. Our findings do not support the replacement of sperm density by male inhibin B when obtaining sperm data is an option.

Antiepileptic drugs alter reproductive endocrine hormones in men with epilepsy

Disturbances of reproductive endocrine hormones are more often found in men with epilepsy than in the general population. There is an ongoing debate whether this can be attributed to chronic use of antiepileptic drugs or to the epilepsy itself. The aim of the present study was to evaluate the degree of endocrine disturbances in men with epilepsy compared with healthy controls, and to investigate whether there was a drug-specific effect of valproate (VPA) or carbamazepine (CBZ). Men with epilepsy, 20-40 years old, having used either VPA (n = 16) or CBZ (n = 19) as monotherapy for >2 years were included and compared with age-matched controls. Men with epilepsy (VPA + CBZ) had significantly lower FSH values and higher C-peptide values compared with controls. Regarding possible drug-specific effects, the VPA treated patients had significantly higher dehydroepiandrosterone (DHEAS) levels and lower FSH and LH concentrations compared with the controls, whereas there were no differences in testosterone, testosterone/sexhormone-binding globulin (SHBG) ratio or androstenedione levels. Men on VPA also had significantly lower free carnitine/total carnitine, which may have implications for sperm motility, and also higher insulin and C-peptide concentrations. The CBZ treated patients had significantly lower testosterone/SHBG ratio than the controls. Compared with the CBZ treated patients, men on VPA had significantly higher DHEAS concentrations and lower levels of follicle stimulating hormone (FSH), luteinizing hormone (LH) as well as a lower free carnitine/total carnitine ratio. A marked age dependency was found in all three groups regarding several of the endocrine hormones. In conclusion, drug-specific endocrine effects of VPA and CBZ were found in men with epilepsy. Long-term VPA treatment leads to significant changes in DHEAS, FSH, LH, insulin, C-peptide and carnitine ratio. Long-term CBZ treatment leads to significant lower testosterone/SHBG ratio. A strict age matching were found to be of importance in the evaluation of endocrine function in men.

Serum inhibin B and follicle-stimulating hormone levels as tools in the evaluation of infertile men: significance of adequate reference values from proven fertile men

Inhibin B and FSH levels in 289 idiopathic infertile men were compared with reference materials consisting of 303 proven fertile men (reference group 1) and 307 healthy men from the general population with unknown fertility status (reference group 2). The diagnostic power of these two serum markers of spermatogenesis was evaluated by the use of receiver operating characteristic plot analysis, and an example of how both markers can be used simultaneously in a bivariate reference chart is presented. Inhibin B levels were significantly lower and FSH levels were significantly higher in the infertile men, compared with either reference group, but with significant overlap, especially with reference group 2. Nevertheless, approximately 50% of the infertile men had an inhibin B or FSH, respectively, below the 2.5 percentile or above the 97.5 percentile of reference group 1, whereas only approximately 25% of the infertile men had an inhibin B or FSH, respectively, below the 2.5 percentile or above the 97.5 percentile of reference group 2. Fourteen and 11% of reference group 2 had an inhibin B or FSH, respectively, below the 2.5 percentile or above the 97.5 percentile of reference group 1, suggesting that a significant number of individuals from the general population with unknown fertility but otherwise healthy may actually be subfertile. In conclusion, 1) proven fertile men constitute the most appropriate reference group in the evaluation of the FSH-inhibin B axis; the sensitivity of these markers to identify infertility increased by approximately 20% when fertile men rather than men from the general population were used as control group; 2) FSH alone had a slightly higher positive predictive value than inhibin B alone, but the positive predictive value were highest when both markers of spermatogenesis were used in an inhibin B/FSH ratio; and 3) a bivariate reference chart is a valuable objective tool in the simultaneous evaluation of FSH and inhibin B as two interrelated markers.

Serum reproductive hormone levels and sperm production in male adult rats after treatment with arresting, a fraction obtained from seminiferous tubules conditioned medium

This study used seminiferous tubule (ST) segments from adult rats to condition culture medium that had been concentrated, size fractioned and administered 10-84 days to adult rats by subcutaneous or intratesticular injection and the effects on testes weight, testosterone, luteinizing hormone (LH) and FSH levels and (homogenization-resistant) epididymal sperm count were determined. The conditioned medium obtained 2 days after culture of ST was fractionated in a 30-100 kDa component. The fraction was injected subcutaneously or intratesticularly. This factor(s), named arresting, decreases sperm count in the epididymis from 13 days to 84 days of treatment without changes in serum LH or testosterone levels. The results of the present study suggest that arresting acts on spermiogenesis/spermiation and/or the entry of sperm into the epididymis from the efferent ductules.

[Inhibins, activins and anti-Müllerian hormone: structure, signalling pathways, roles and predictive value in reproductive medicine]

Anti-Müllerian hormone (AMH), inhibins and activins are members of the transforming growth factor (TGFbeta) superfamily and are known to have a variety of actions concerning reproduction, hormonogenesis, development processes and differentiation. Inhibins and activins are dimeric glycoproteins that are defined by their actions on the pituitary gonadotroph cells. AMH, inhibins and activins have a vast array of actions usually exerted through paracrine and endocrine mechanisms. The recent availability of specific inhibin assays has demonstrated that inhibin B is the relevant circulating inhibin form in the human male. Inhibin B seems to be a useful marker of spermatogenesis, but serum and seminal inhibin B levels are not predictive parameters for the selection of azoospermic men as candidates for testicular sperm extraction (TESE). AMH in seminal plasma may be important for sperm production, and is a good marker for sertoli cell development. It might be the only one seminal marker of spermatogenesis in non-obstructive azoospermia. Nevertheless, many of these studies were carried out with small patient numbers, and consequently must be interpreted with caution. In women ongoing assisted reproductive therapy (ART), day 3 inhibin B and AMH levels predict the number of oocytes retrieved, but cannot predict likelihood of pregnancy. Further studies are needed to determine if AMH and inhibin predict ART outcomes better than classical parameters (age, FSH levels and follicular ultrasonography). AMH and inhibin are also specific markers of Sertoli- and granulosa-cell origin in gonadal tumors.

Effects of low concentrations of inhibin B on the outcomes of testicular sperm extraction and intracytoplasmic sperm injection

OBJECTIVE

To study the effects of undetectable inhibin B concentrations on the outcomes of testicular sperm extraction (TESE) and of intracytoplasmic sperm injection (ICSI).

DESIGN

Retrospective study.

SETTING

Obstetrics, gynecology, and reproductive biology departments.

PATIENT(S)

We carried out TESE on 75 men with nonobstructive azoospermia: 42 men had an inhibin B concentration of <m15 pg/mL (group 1), and 33 had an inhibin B concentration of > or = 15 pg/mL (group 2). Twenty-five ICSI cycles were carried out using sperm from men in group 1 (group A1), and 35 ISCI cycles were carried out using sperm from men in group 2 (group A2). The outcomes of ICSI in groups A1 and A2 were compared with those of 81 ICSI cycles performed for obstructive azoospermia (group B).

INTERVENTION(S)

Testicular sperm extraction, testicular spermatozoa cryopreservation, and ICSI.

MAIN OUTCOME MEASURE(S)

Testicular sperm extraction outcome, pregnancy, and delivery.

RESULT(S)

Sperm were significantly less likely to be successfully recovered from men in group 1 than from those in group 2 (21% vs. 48%). The inhibin B concentration was significantly lower in men in whom TESE failed, but the FSH concentration did not differ. The implantation rate per embryo transferred was twofold lower in group A1 (7.4%) than in group B (16%), but this difference is not statistically significant.

CONCLUSION(S)

Patients with undetectable inhibin B concentration should be informed of the low chances of positive testicular biopsy, and more embryos should be transferred to improve the success rate.

Immunolocalization of inhibin and activin alpha and betaB subunits and expression of corresponding messenger RNAs in the human adult testis

Inhibin B is a testicular peptide hormone that regulates FSH secretion in a negative feedback loop. Inhibin B is a dimer of an alpha and a beta(B) subunit. In adult testes, the cellular site of production is still controversial, and it was hypothesized that germ cells contribute to inhibin B production. To determine which cell types in the testes may produce inhibin B, the immunohistochemical localization of the two subunits of inhibin B were examined in adult testicular biopsies with normal spermatogenesis, spermatogenic arrest, or Sertoli cell only (SCO) tubules. Moreover, using in situ hybridization with mRNA probes, the mRNA expression patterns of inhibin alpha and inhibin/activin beta(B) subunits have been investigated. In all testes, Sertoli cells and Leydig cells showed positive immunostaining for inhibin alpha subunit and expressed inhibin alpha subunit mRNA. Using inhibin beta(B) subunit immunoserum on testes with normal spermatogenesis and with spermatogenic arrest, intense labeling was located in germ cells from pachytene spermatocytes to round spermatids but not in Sertoli cells. Inhibin beta(B) subunit mRNA expression was intense in germ cells from spermatogonia to round spermatids and in Sertoli cells in these testes. In testes with SCO, high inhibin beta(B) subunit mRNA labeling density was observed in both Sertoli cells and Leydig cells, whereas beta(B) subunit immunostaining was negative for Sertoli cells and faintly positive for Leydig cells. These results agree with the recent opinion that inhibin B in adult men is possibly a joint product of Sertoli cells and germ cells.

Serum levels of inhibin B and follicle-stimulating hormone may predict successful sperm retrieval in men with azoospermia who are undergoing testicular sperm extraction

To evaluate the predictive power for sperm retrieval in testicular sperm extraction of inhibin B and FSH levels in the peripheral blood in association with the testicular histology. Clinical study. Departments of andrology and urology at a university hospital.Fifty-two patients with azoospermia. Determination of serum levels of FSH and inhibin B in men with azoospermia. Testicular incision and histological investigation as well as testicular sperm extraction (TESE) followed by intracytoplasmic sperm injection were performed. Comparison of hormone levels with different histological features of seminiferous tubules (normospermatogenesis, hypospermatogenesis, and Sertoli cell-only syndrome) and TESE outcome.With respect to the histological proof of spermatozoa, the sensitivity of the FSH levels >10 mU/mL was 82%, and of inhibin B levels, <79 pg/mL, 78%; the specificity was 80% for both hormone levels. With respect to the successful sperm extraction in the TESE procedure, the sensitivity of the FSH levels was 58% and the specificity was 50%; and the sensitivity of inhibin B levels was 52.5% and the specificity was 60%. Inhibin B and FSH levels are correlated with spermatogenetic activity. The combination of the two parameters is currently the best predictor for the presence of sperm, which may be found in TESE. However, the prediction is not absolutely reliable: TESE can be also successful when both hormone levels are outside the threshold levels.

Serum levels of inhibin B in men and their relationship with gonadal hormones, testicular volume, testicular biopsy results and sperm parameters

Currently, serum inhibin B levels, indicating testicular function due directly to its testicular origin, has been used increasingly in assisted reproductive units. Our aim in this prospective study was to evaluate the biological significance of inhibin B in gonadal dysfunctional males and the usefulness of inhibin B for the detection of male reproductive dysfunction. We included 52 oligoazoospermic and 20 normospermic men in this study. In our study serum inhibin B levels had statistically significant negative correlation with serum FSH and LH levels (P < 0.001, r: 0.781) and statistically moderate positive correlation with oestradiol levels (P < 0.005, r: 0.292). Inhibin B levels had significantly positive correlation with sperm count (P < 1.005, r: 0.851) and with testicular volume (P < 0.001, r: 0.466). Consequently, serum inhibin B level determination is a useful and non-invasive method for the evaluation of male gonadal dysfunction, taking into account its correlation with history, clinical examination, hormonal parameters, testicular volume, spermiogram and testicular biopsy.

Low birth weight for gestational age and subsequent male gonadal function

OBJECTIVE

To verify whether a reduced birth weight for gestational age was associated with a testicular dysfunction in postpubertal boys.

STUDY DESIGN

Boys born small for gestational age (SGA) (n = 25) were compared to 24 born with an appropriate weight. All subjects were postpubertal (mean age 17.5 +/- 1.3 and 17.6 +/- 2.0 years, respectively). The following clinical and endocrinologic variables were evaluated: final height, target height, body mass index, testicular volume, follicle-stimulating hormone, luteinizing hormone, testosterone, and inhibin B.

RESULTS

The SGA group had reduced testicular size (16.3 +/- 2.7 mL vs 22.8 +/- 3.2 mL; P <.0001) with a lower testosterone level (3.76 +/- 1.35 ng/mL vs 4.77 +/- 1.55 ng/mL; P <.05) and a higher LH value (4.41 +/- 1.61 IU/L vs 3.44 +/- 1.29 IU/L; P <.05). Among the SGA group, 54% had a mean testicular volume >2 SD below the control mean (ie, <16 mL) and in these subjects, the inhibin B level was low (143 +/- 46 pg/mL vs 229 +/- 76 pg/mL; P <.0001). SGA patients with smaller testes had lower final height relative to target height(P <.05 vs patients with larger testes) and for the SGA group, inhibin B correlated with testicular size (P <.0001). Positive correlations also were found between the reduction of final height relative to target height and testicular volume (P <.005) and inhibin B values (P <.05).

CONCLUSIONS

SGA subjects have pituitary-gonadal axis function that tends toward hypogonadism. There is a disruption of the exocrine function in subjects with smaller testicular size who failed to show a complete height catch-up growth. This study supports a link between low birth weight and lower fertility in adult males.

Investigation of suppression of the hypothalamic-pituitary-gonadal axis to restore spermatogenesis in azoospermic men treated for childhood cancer

BACKGROUND

Does suppression of the hypothalamic-pituitary-gonadal (HPG) axis restore spermatogenesis in men rendered azoospermic following treatment of childhood cancer?

METHODS

Seven men with azoospermia secondary to treatment for childhood cancer, median age (range), 22.2 (18-25.3) years, aged 10.4 (4.4-13.3) years at original diagnosis, participated. Each subject underwent semen analysis and testicular biopsy, followed by treatment with medroxyprogesterone acetate (MPA), 300 mg i.m. repeated after 12 weeks, with 800 mg testosterone pellets s.c. on day 1 to suppress the HPG axis. Hormone and semen analysis was performed every 6 weeks for 48 weeks. A second testicular biopsy was performed at week 48.

RESULTS

Before HPG axis suppression, mean +/- SEM plasma LH was 9.0 +/- 1.8 U/l, testosterone 17.9 +/- 1.5 nmol/l and FSH 22.4 +/- 4.4 U/l. Median (range) venous plasma and seminal plasma inhibin B levels were 10.0 (7.8-35) and 11.2 (7.8-770) ng/l respectively. During HPG suppression, FSH and LH levels were undetectable for > or =12 weeks followed by a gradual return to pretreatment concentrations by 48 weeks. All men remained azoospermic at study completion and complete absence of germ cells on biopsies was demonstrated by immunocytochemistry for all specimens pre- and post-HPG axis suppression.

CONCLUSIONS

HPG axis suppression with MPA-testosterone for > or =12 weeks did not restore spermatogenesis in azoospermic men treated with gonadotoxic radiotherapy and chemotherapy for childhood cancer.

Factors affecting gonadal function after bone marrow transplantation during childhood

Conditioning for bone marrow transplantation (BMT) may alter viability of germ cells and production of gonadal hormones. We analyzed the risk factors for gonadal failure after 12 Gy total body irradiation (TBI) given as six fractions (n = 31, group 1), 10 Gy (one dose) TBI (n = 20, group 2), 6 Gy (one dose) total lymphoid irradiation (TLI, n = 17, group 3) and chemotherapy alone (n = 7, group 4), given at 7.7 +/- 0.4 (0.6-13.6) years. Among the 34 girls, seven (20.6%) had normal ovarian function with regular spontaneous menstruation and normal plasma follicle-stimulating (FSH) and luteinizing (LH) hormones, five (14.7%) had partial ovarian failure with regular menstruation but increased FSH and/or LH, and 22 (64.7%) had complete ovarian failure. The 24 girls with chronological and bone ages >13 years included similar percentages, with increased FSH or LH in all four groups. There was a positive correlation between age at BMT and FSH (r = 0.54, P < 0.01), but not with lh, and between fsh and lh (r = 0.8, P = 0.0003). Plasma FSH concentrations had returned to normal spontaneously in six cases, and those of LH in two cases. Among the 41 boys, 16 (39%) had normal testicular function and 25 (61%) had tubular failure and increased FSH. Of these, 10 also had Leydig cell failure (three complete and seven partial). The 18 boys with chronological and bone ages >15 years included similar percentages with increased FSH or LH in groups 1 to 3, and testicular volume was significantly lower in group 2 than in group 3 (P = 0.008). There was no correlation between age at BMT and FSH, LH or testosterone, but there was a negative correlation between FSH and inhibin B (rho = -0.87, P < 0.003). we conclude that girls are more likely to suffer ovarian failure the older they are at bmt, and that early ovarian recovery is possible. the negative correlation between fsh and inhibin b in boys suggests that this parameter is an additional indicator of tubular function.