Serum inhibin B in healthy pubertal and adolescent boys: relation to age, stage of puberty, and follicle-stimulating hormone, luteinizing hormone, testosterone, and estradiol levels

Trajectory of Gonadal Hormones in Adolescent Males up to 2 Years After Sleeve Gastrectomy

Sleeve gastrectomy (SG) has many metabolic benefits and leads to improvements in testosterone levels, which means improvement in the Leydig cell function of the testis. However, data about the effects of SG on Sertoli cell function (as assessed by inhibin B) are not available. In this preliminary study, we evaluate, for the first time, the effect of SG in adolescents after SG. We evaluate 16 adolescent and young adult males, six of whom underwent SG and followed them for 2 years. We report that Leydig cell function (as assessed by testosterone levels) improved and was associated with degree of weight loss. Sertoli cell function improved only slightly in SG group and did not change compared to the nonsurgical controls, and these changes were not associated with degree of weight loss. Thus, we conclude that larger and long-term follow-up studies are required to evaluate the changes in Sertoli cell function after SG as that is integral to male fertility.Clinical Trial Registration: NCT02557438.

Quantification of urinary total luteinizing hormone immunoreactivity may improve the prediction of ovulation time

OBJECTIVES

Most of the currently available ovulation prediction kits provide a relatively rough estimation of ovulation time with a short fertility window. This is due to their focus on the maximum probability of conception occurring one day before ovulation, with no follow-up after LH surge until ovulation nor during the subsequent days thereafter. Earlier studies have shown that urine of reproductive age women contains at least 3 different molecular forms of luteinizing hormone (LH); 1) intact LH, 2) LH beta-subunit (LHβ) and a 3) small molecular weight fragment of LHβ, LHβ core fragment (LHβcf). The proportion of these LH forms in urine varies remarkably during the menstrual cycle, particularly in relation to the mid-cycle LH surge. In this exploratory study, we studied the potential implications of determining the periovulatory course of total LH immunoreactivity in urine (U-LH-ir) and intact LH immunoreactivity in serum (S-LH-ir) in the evaluation of the fertility window from a broader aspect with emphasis on the post-surge segment.

METHODS

We determined total U-LH-ir in addition to intact S-LH-ir, follicle-stimulating hormone (FSH), progesterone, and estradiol in 32 consecutive samples collected daily from 10 women at reproductive age. Inference to the non-intact U-LH-ir levels was made by calculating the proportion of total U-LH-ir to intact S-LH-ir.

RESULTS

Total U-LH-ir increased along with LH surge and remained at statistically significantly higher levels than those in serum for 5 consecutive days after the surge in S-LH-ir. S-LH-ir returned to follicular phase levels immediately on the following day after the LH surge, whereas the same took 7 days for total U-LH-ir.

CONCLUSIONS

The current exploratory study provides preliminary evidence of the fact that U-LH-ir derived from degradation products of LH remains detectable at peak levels from the LH surge until ovulation and further during the early postovulatory period of fecundability. Thus, non-intact (or total) U-LH-ir appears to be a promising marker in the evaluation of the post-surge segment of the fertility window. Future studies are needed to unravel if this method can improve the prediction of ovulation time and higher rates of fecundability in both natural and assisted conception.

Insulin-like peptide 3 (INSL3) in congenital hypogonadotrophic hypogonadism (CHH) in boys with delayed puberty and adult men

BACKGROUND

Delayed puberty in males is almost invariably associated with constitutional delay of growth and puberty (CDGP) or congenital hypogonadotrophic hypogonadism (CHH). Establishing the cause at presentation is challenging, with "red flag" features of CHH commonly overlooked. Thus, several markers have been evaluated in both the basal state or after stimulation e.g. with gonadotrophin releasing hormone agonist (GnRHa).Insulin-like peptide 3 (INSL3) is a constitutive secretory product of Leydig cells and thus a possible candidate marker, but there have been limited data examining its role in distinguishing CDGP from CHH. In this manuscript, we assess INSL3 and inhibin B (INB) in two cohorts: 1. Adolescent boys with delayed puberty due to CDGP or CHH and 2. Adult men, both eugonadal and having CHH.

MATERIALS AND METHODS

Retrospective cohort studies of 60 boys with CDGP or CHH, as well as 44 adult men who were either eugonadal or had CHH, in whom INSL3, INB, testosterone and gonadotrophins were measured. Cohort 1: Boys with delayed puberty aged 13-17 years (51 with CDGP and 9 with CHH) who had GnRHa stimulation (subcutaneous triptorelin 100mcg), previously reported with respect to INB. Cohort 2: Adult cohort of 44 men (22 eugonadal men and 22 men with CHH), previously reported with respect to gonadotrophin responses to kisspeptin-54.

RESULTS

Median INSL3 was higher in boys with CDGP than CHH (0.35 vs 0.15 ng/ml; p=0.0002). Similarly, in adult men, median INSL3 was higher in eugonadal men than CHH (1.08 vs 0.05 ng/ml; p<0.0001). However, INSL3 more accurately differentiated CHH in adult men than in boys with delayed puberty (auROC with 95% CI in adult men: 100%, 100-100%; boys with delayed puberty: 86.7%, 77.7-95.7%).Median INB was higher in boys with CDGP than CHH (182 vs 59 pg/ml; p<0.0001). Likewise, in adult men, median INB was higher in eugonadal men than CHH (170 vs 36.5 pg/ml; p<0.0001). INB performed better than INSL3 in differentiating CHH in boys with delayed puberty (auROC 98.5%, 95.9-100%), than in adult men (auROC 93.9%, 87.2-100%).

CONCLUSION

INSL3 better identifies CHH in adult men, whereas INB better identifies CHH in boys with delayed puberty.

Relationships of sex hormones with muscle mass and muscle strength in male adolescents at different stages of puberty

This study analysed the associations of sex steroids with fat-free mass (FFM) and handgrip strength in 641 Chinese boys. Serum total testosterone (TT) and oestradiol were measured by chemiluminescence immunoassay. Free testosterone (FT) and oestradiol were calculated. FFM and handgrip strength were measured by bioelectrical impedance analysis and a hand dynamometer, respectively. Generalised additive models and multiple linear regression were used to explore the relationships. A subgroup analysis was conducted in early-mid pubertal and late-post pubertal groups. Age, height, weight, physical activity, intake of dietary protein and/or stage of puberty were adjusted. TT and FT were positively related to FFM and handgrip strength, with a curvilinear relationship being detected for handgrip strength (p<0.050). This curvilinear relationship was only observed in the late-post pubertal group, suggesting a potential threshold effect (FT>11.99ng/dL, β = 1.275, p = 0.039). In the early-mid pubertal group, TT and/or FT were linearly or near-linearly related to FFM or handgrip strength (β = 0.003-0.271, p<0.050). The association between FT and FFM was stronger than that in the late-post pubertal group. This study found that serum T had different associations with muscle parameters in Chinese early-mid pubertal and late-post pubertal boys. In the late-post pubertal boys, serum T was curvilinearly related to muscle strength with a threshold effect and its link with muscle mass was weaker.

Interpretation of reproductive hormones before, during and after the pubertal transition-Identifying health and disordered puberty

Puberty is a process of transition from childhood to adult reproductive capacity, governed by the reactivation of the hypothalamic-pituitary-gonadal axis after a long period of dormancy in mid-childhood. As such, the reproductive hormones are in a state of flux during the adolescent years, and interpretation of both the onset of healthy, concordant puberty and the differentiation of precocious, delayed or disordered puberty, can be challenging. This review is focused on the description of the endocrine axes in healthy puberty and the markers of disorders of puberty that can aid diagnosis and management for patients with these conditions. It will cover the hypothalamic, pituitary and gonadal hormone systems, the dynamic changes that occur during puberty, conditions leading to precocious, delayed or absent puberty and other syndromes with disordered puberty, and the biochemical diagnosis of these different disorders of puberty.

Circulating sex steroids and bladder pain sensitivity in dysmenorrhea

Although elevated estradiol levels facilitate chronic pelvic pain in animal models, it remains to be determined whether sex steroid levels are altered in a cross-section of women with chronic pelvic pain (CPP) and those at-risk for developing CPP. We sought to determine if sex steroid levels are increased in women with menstrual pain and whether those changes were more extreme in two groups of women with worsened pelvic pain profiles: a) dysmenorrhea plus evidence of bladder pain sensitivity and b) bladder pain syndrome. Serum samples were collected during the mid-luteal phase to measure estradiol, progesterone, testosterone, and sex hormone-binding globulin. We also compared quantitative sensory testing profiles to evaluate how sex steroid differences influence proposed pain sensitivity mechanisms. Women with combined dysmenorrhea and bladder sensitivity had higher estradiol concentrations than controls (487 [IQR 390 - 641] vs 404 [336 - 467] pmol/L, p = 0.042). Bladder pain syndrome participants had greater sex hormone-binding globulin than controls (83 [71 - 108] vs 55 [42 - 76 nmol/L; p = 0.027). Levels of pain sensitivity and mood were different across the groups, but the only significant relationship to sex steroids was that sex hormone-binding globulin was correlated to somatic symptoms (r = 0.26, p = 0.03). These findings show women potentially at-risk for CPP and women with diagnosed CPP exhibit altered circulating levels of sex steroids. Because these hormonal differences appear to be independent of mood or pain sensitivity, the role of sex steroids in the emergence of CPP may be via sensitization of visceral afferents.

Clinical, Biochemical, and Molecular Characterization of Indian Children with Clinically Suspected Androgen Insensitivity Syndrome

This study describes the clinical, biochemical, and molecular characteristics of Indian children with 46,XY DSD and suspected androgen insensitivity syndrome (AIS). Fifty children (median age 3.0 years, range 0-16.5 years) with 46,XY DSD and a suspected diagnosis of AIS were enrolled. Sanger sequencing was performed to identify pathogenic variants in the androgen receptor (AR) gene and to study genotype-phenotype correlations. All 5 (100%) patients with CAIS and 14/45 (31%) patients with PAIS had pathogenic/likely pathogenic variants in the AR gene (overall, 14 different variants in 19 patients; 38.8%). There was no significant difference in clinical (cryptorchidism, hypospadias, or external masculinizing score) or biochemical parameters (gonadotropins and testosterone) between patients with or without pathogenic variants. However, patients with AIS were more likely to have a positive family history, be assigned female gender at birth, and present with gynaecomastia at puberty. Three novel pathogenic/likely pathogenic variants, including one splice donor site variant c.2318+1G>A, one frameshift variant p.H790Lfs*40, and one missense variant p.G821E, were identified in 3 patients with CAIS. The missense variant p.G821E was predicted as deleterious, damaging, disease-causing, and likely functionally inactive by in silico analysis and protein modelling study. Two previously not reported pathogenic/likely pathogenic variants, including p.R386H and p.G396R, were identified in patients with PAIS. This study contributes in expanding the spectrum of pathogenic variants in the AR gene in patients with AIS. Only 31% patients with a provisional diagnosis of PAIS had pathogenic variants in the AR gene, suggesting other possible mechanisms or candidate genes may be responsible for such a phenotypic presentation.

Childhood reproductive hormone levels after pediatric hematopoietic stem cell transplantation in relation to adult testicular function

OBJECTIVES

Longitudinal assessment of testicular function after pediatric hematopoietic stem cell transplantation (HSCT) is needed to guide clinical follow-up. We investigated dynamics in male reproductive hormones after pediatric HSCT, focusing on pubertal timing and associations with testosterone deficiency and azoospermia in adulthood.

METHODS

This retrospective, longitudinal study included 39 survivors median 19 years after pediatric HSCT. Serum concentrations of LH, testosterone, FSH, and inhibin B from the time of HSCT, during puberty, and into adulthood were analyzed. Pubertal timing (rise in LH and testosterone) was compared to a reference cohort of 112 healthy boys. Associations between reproductive hormone levels during puberty and adult testicular function (including semen quality) were investigated.

RESULTS

Pubertal induction with testosterone was needed in 6/26 patients who were prepubertal at HSCT. In the remaining patients, pubertal timing was comparable to the reference cohort. However, 9/33 patients (without pubertal induction) developed testosterone deficiency in early adulthood, which was associated with higher LH levels from age 14 to 16 years. Azoospermia in adulthood was found in 18/26 patients without testosterone substitution. Higher FSH and lower inhibin B levels from mid-pubertal age were associated with azoospermia in adulthood, in patients being prepubertal at HSCT.

CONCLUSION

Our results indicate a substantial risk of deterioration in testicular function after pediatric HSCT, despite normal pubertal timing. Although reproductive hormone levels from mid-puberty indicated adult testicular function, prolonged follow-up into adulthood is needed in these patients, including clinical examination, reproductive hormone analysis, and semen sample for patients interested in their fertility potential.

National School-Based Health Lifestyles Intervention in Chinese Children and Adolescents on Obesity and Hypertension

Introduction: This study aimed to examine the effectiveness of the national school-based intervention on both obesity and high blood pressure in Chinese children and adolescents aged 6-18 years. Methods: The national school-based cluster non-randomized controlled trial was done in seven provinces from September 2013 to February 2014. A total of 23,175 children and adolescents in the control group and 25,702 in the intervention group were included in this trial with a mean follow-up of 6.7 ± 0.9 months. Mixed-effects regression models were used to evaluate the effect of the interventions on body weight and blood pressure (BP). Results: A significant upward in the body mass index (BMI) levels but downward in systolic BP (SBP), diastolic BP (DBP), BMI Z-scores, SBP Z-scores, and DBP Z-scores were witnessed in the intervention group compared to those in the control group (<0.001). Subgroup analyses presented significant intervention effects in children aged 6-12 years for BMI, SBP, DBP, and their standardized values Z-scores, but no effective results were found in adolescents aged 13-18 years. Stratification analyses based on the dynamic weight changes presented non-differential HBP, SHBP, and DHBP prevalence gaps between the control and intervention groups. Children aged 6-12 years with higher BMI percentiles at baseline presented obvious declines in SBP and DBP standardized values Z-scores. Conclusion: A mean 6-month multi-centered school-based comprehensive obesity intervention in China yields a small to null effect on obesity and hypertension with increasing age; the early age before 12 years may be the key period for interventions, and the younger, the better. Precise and high-intensity interventions targeting the population at different stages of childhood and adolescence are urgently needed to be developed. Clinical Trial Registration: https://www.clinicaltrials.gov/, identifier: NCT02343588.

Treatment of gonadotropin deficiency during the first year of life: long-term observation and outcome in five boys

STUDY QUESTION

What is the peripubertal outcome of recombinant human FSH (r-hFSH) treatment during minipuberty in boys with congenital hypogonadotropic hypogonadism (CHH)?

SUMMARY ANSWER

Sertoli-cell response to r-hFSH, given during the minipuberty of infancy, appears insufficient to maintain Sertoli cell function throughout childhood, as evaluated by inhibin B measurements.

WHAT IS KNOWN ALREADY

Severe CHH in boys can be diagnosed during the minipuberty of infancy. Combined gonadotropin treatment at that age is suggested to improve testicular endocrine function and future fertility, yet long-term evidence is lacking.

STUDY DESIGN, SIZE, DURATION

In this retrospective cohort study, we describe five CHH boys treated with r-hFSH in Helsinki University Hospital or Kuopio University Hospital between 2004 and 2018. Immediate follow-up data (0.1-1.4 months after cessation of the gonadotropin therapy) was available for four boys and long-term observations (at the age of 10.0-12.8 years) was available for three boys. As a retrospective control cohort, we provide inhibin B values of eight untreated CHH boys at the age of 12.7-17.8 years.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Four patients had combined pituitary hormone deficiency, and one had CHARGE syndrome due to a CHD7 mutation. The patients were treated at the age of 0.7-4.2 months with r-hFSH (3.4 IU/kg-7.5 IU/kg per week in 2 or 3 s.c. doses for 3-4.5 months) combined with T (25 mg i.m. monthly for three months for the treatment of micropenis). Inhibin B was chosen as the primary outcome measure.

MAIN RESULTS AND THE ROLE OF CHANCE

During the r-hFSH + T treatment, inhibin B increased from 76 ± 18 ng/l to 176 ± 80 ng/l (P = 0.04) and penile length increased by 81 ± 50% (P = 0.04). Unexpectedly, two boys with robust inhibin B responses in infancy demonstrated low inhibin B values in peripuberty: declining from 290 ng/l (4 months) to 16 ng/l (12.4 years), and from 207 ng/l (6 months) to 21 ng/l (12.8 years). All boys underwent orchiopexy at 2.0 ± 0.7 years of age. Inhibin B values in long-term follow-up, available for the three boys, did not significantly differ from the untreated CHH controls.

LIMITATIONS, REASONS FOR CAUTION

Limitations of this retrospective study are the small number and heterogeneity of the patients and their treatment schemes.

WIDER IMPLICATIONS OF THE FINDINGS

We describe the first long-term follow-up data on CHH boys treated with r-hFSH and T as infants. The results from this small patient series suggest that the effects of infant r-hFSH treatment may be transient, and further longitudinal studies are required to determine the efficacy of this treatment approach to optimise the fertility potential in this patient population.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by the Finnish foundation for Pediatric Research, the Academy of Finland and the Emil Aaltonen Foundation. The authors have no competing interests.

TRIAL REGISTRATION NUMBER

Non-applicable.

Association between acrylamide exposure and sex hormones in males: NHANES, 2003-2004

Introduction

Acrylamide is widely present in heat-processed food, cigarette smoke and environment. Reproductive toxicity was reported in animals treated with acrylamide, particularly in males. The reproductive toxicity of acrylamide and its active metabolite, glycidamide, was reported to be mainly mediated through DNA damage in spermatocytes. However, the effect of acrylamide on sex hormones in men is unknown.

Methods

There were 468 male subjects (age ≧ 12 years) enrolled to determine the relationships between hemoglobin adducts of acrylamide (HbAA) and hemoglobin adducts of glycidamide (HbGA) with several sex hormones using the National Health and Nutrition Examination Survey (NHANES), 2003 to 2004. All potential confounding variables in the data set were properly adjusted.

Results

We found that one unit increase in the natural log-transformed HbAA level was associated with an increase in natural log transformed serum inhibin B level by 0.10 (SE = 0.05; P = 0.046), and natural log transformed serum sex hormone binding globulin (SHBG) by 0.15 (SE = 0.15; P = 0.036). With respect to HbGA, one unit increase in the natural log-transformed HbGA level was associated with an increase in natural log transformed serum anti-Müllerian Hormone (AMH) level by 0.31 (SE = 0.00; P = 0.003).

Conclusion

In this representative cohort, we identified positive associations between acrylamide exposure and several sex hormones in men. The HbAA is positively associated with inhibin B and SHBG, and HbGA is positively associated with AMH. Other than genotoxicity, our findings suggested that altered sex hormones might also play a role in acrylamide-related reproductive toxicity in males.

Reference range and cutoff value of serum inhibin B to predict successful sperm retrieval: A cross-sectional study of 30 613 Chinese men

BACKGROUND

The power of inhibin B to predict competent spermatogenesis is not fully understood. The aims of this study were to identify the reliable reference range of inhibin B among normozoospermic men in China and to evaluate the diagnostic accuracy of serum inhibin B level as a complementary predictor of successful sperm retrieval in patients with azoospermia.

METHODS

This was a cross-sectional study. The male partners of 30 613 infertile couples who visited our hospital were investigated between March 2017 and March 2019. We analysed semen parameters, serum levels of reproductive hormones (inhibin B, FSH and testosterone) and sperm retrieval results from PESA/TESE in Chinese men.

RESULTS

The normal reference range of inhibin B was 87.42-299.93 pg/mL among men with normozoospermia in China. Inhibin B levels were negatively correlated with age (r = -.111; P < .001) but positively correlated with total sperm counts in the overall population, reference group and case group (r = .311, r = .208 and r = .444, respectively; P < .001). Stepwise multiple regression analyses revealed that compared with the FSH and testosterone levels, the inhibin B level had the closest relationship with the total sperm count. The best cutoff value of inhibin B for predicting the retrieval outcome of testicular/epididymal sperm was >77.72 pg/mL (sensitivity = 59.14%, specificity = 92.00% and AUC = 0.801). The inhibin B:FSH ratio (cutoff value > 6.98, sensitivity = 56.99%, specificity = 96.00% and AUC = 0.814) performed better than either the inhibin B level or the FSH level alone.

CONCLUSION

A new reference range for serum inhibin B was established in China. However, neither serum inhibin B, FSH nor their ratio is adequate for men to decide whether to undergo PESA/TESE to determine the adequacy of spermatogenesis.

Estrogens in Human Male Gonadotropin Secretion and Testicular Physiology From Infancy to Late Puberty

Several reports in humans as well as transgenic mouse models have shown that estrogens play an important role in male reproduction and fertility. Estrogen receptor alpha (ERα) and beta (ERβ) are expressed in different male tissues including the brain. The estradiol-binding protein GPER1 also mediates estrogen action in target tissues. In human testes a minimal ERα expression during prepuberty along with a marked pubertal up-regulation in germ cells has been reported. ERβ expression was detected mostly in spermatogonia, primary spermatocytes, and immature spermatids. In Sertoli cells ERβ expression increases with age. The aromatase enzyme (cP450arom), which converts androgens to estrogens, is widely expressed in human tissues (including gonads and hypothalamus), even during fetal life, suggesting that estrogens are also involved in human fetal physiology. Moreover, cP450arom is expressed in the early postnatal testicular Leydig cells and spermatogonia. Even though the aromatase complex is required for estrogen synthesis, its biological relevance is also related to the regulation of the balance between androgens and estrogens in different tissues. Knockout mouse models of aromatase (ArKO) and estrogen receptors (ERKOα, ERKOβ, and ERKOαβ) provide an important tool to study the effects of estrogens on the male reproductive physiology including the gonadal axis. High basal serum FSH levels were reported in adult aromatase-deficient men, suggesting that estrogens are involved in the negative regulatory gonadotropin feedback. However, normal serum gonadotropin levels were observed in an aromatase-deficient boy, suggesting a maturational pattern role of estrogen in the regulation of gonadotropin secretion. Nevertheless, the role of estrogens in primate testis development and function is controversial and poorly understood. This review addresses the role of estrogens in gonadotropin secretion and testicular physiology in male humans especially during childhood and puberty.

Puberty and Inhibin B in 35 Adolescents With Pituitary Stalk Interruption Syndrome

Background: In patients with pituitary stalk interruption syndrome (PSIS), long-term follow-up is necessary to address their gonadotrophic status. The objectives of this study were (1) to describe pubertal features of and (2) to assess the ability of serum inhibin B concentration to predict hypogonadotropic hypogonadism (HH) in patients with PSIS. Methods: This retrospective single-center study included 35 patients with PSIS and known gonadotrophic status for whom a serum sample preserved at -22°C (collected at initial evaluation or later) was available for measuring inhibin B by the same hormonal immunoassay method. Results: Among the 21 boys, 15 had normal puberty (early in two), and six had partial (n = 2) or complete (n = 4) HH. Among the 14 girls, five had normal puberty (early in one)-four with regular menses and one in the process of puberty-, four had complete HH, and five had amenorrhea (primary in three and secondary in two) after normal pubertal development, despite a normal pubertal gonadotropin response to gonadotropin-releasing hormone test. These were considered as having partial HH. Only three boys had values over the normal lower range for serum inhibin B concentrations despite partial (n = 2) or complete (n = 1) HH. Inhibin B concentrations were low in all girls with complete HH, normal in all those with partial HH except in one and in those with normal puberty except in two. Considering boys and girls together, the occurrence of under-range inhibin B was significantly higher in those with HH than in those without (47 vs. 10%, p = 0.02). All 15 patients with HH had associated thyroid-stimulating hormone and adrenocorticotropic hormone deficiency except for 3 girls with partial HH. Conclusions: Under-range inhibin B concentrations in patients with PSIS might be suggestive of HH. These concentrations provide a simple first-line predictive test, especially in boys.

Adrenal and Gonadal Activity, Androgen Concentrations, and Adult Height Outcomes in Boys With Silver-Russell Syndrome

Background: We have previously shown that adult height (AH) in males with Silver-Russell syndrome (SRS) correlated negatively with prepubertal estradiol concentrations. We aimed to identify the source of estradiol by analyzing androgen secretion profiles and measuring anti-Müllerian hormone (AMH) and inhibin B concentrations during childhood and puberty in this group of patients. Methods: In a retrospective longitudinal single-center study, 13 males with SRS were classified as non-responders (NRs = 8) or responders (Rs = 5), depending on the AH outcome. From 6 years of age, androgens were determined by mass spectrometry, and AMH, inhibin B and sex hormone-binding globulin concentrations were analyzed by immunoassays. Results: AH outcome correlated negatively with dehydroepiandrosterone-sulfate (DHEAS) at 8 (r = -0.72), 10 (r = -0.79), and 12 years (r = -0.72); testosterone at 10 (r = -0.94), 12 (r = -0.70) and 14 years (r = -0.64); dihydrotestosterone (DHT) at 10 (r = -0.62) and 12 years; (r = -0.57) and AMH at 12 years (r = 0.62) of age. Compared with Rs, NRs had higher median concentrations of DHEAS (μmol/L) at 10 years (2.9 vs. 1.0); androstenedione (nmol/L) at 10 (1.1 vs. 0.6) and 12 years (1.7 vs. 0.8); testosterone (nmol/L) at 10 (0.3 vs. 0.1), 12 (7.8 vs. 0.2) and 14 years (15.6 vs. 10.4); and DHT (pmol/L) at 10 (122 vs. 28) and 12 years (652 vs. 59) of age. AMH (ng/mL) was lower in NRs than in Rs at 12 years of age (11 vs. 50). No significant differences were observed in the inhibin B concentrations at any age. Conclusions: The elevated androgen concentrations before and during puberty, originated from both adrenal and gonadal secretion and correlated negatively with AH outcomes in males with SRS.

Hypogonadism and Cryptorchidism

Congenital cryptorchidism (undescended testis) is one of the most common congenital urogenital malformations in boys. Prevalence of cryptorchidism at birth among boys born with normal birth weight ranges from 1.8 to 8.4%. Cryptorchidism is associated with a risk of low semen quality and an increased risk of testicular germ cell tumors. Testicular hormones, androgens and insulin-like peptide 3 (INSL3), have an essential role in the process of testicular descent from intra-abdominal position into the scrotum in fetal life. This explains the increased prevalence of cryptorchidism among boys with diseases or syndromes associated with congenitally decreased secretion or action of androgens, such as patients with congenital hypogonadism and partial androgen insensitivity syndrome. There is evidence to support that cryptorchidism is associated with decreased testicular hormone production later in life. It has been shown that cryptorchidism impairs long-term Sertoli cell function, but may also affect Leydig cells. Germ cell loss taking place in the cryptorchid testis is proportional to the duration of the condition, and therefore early orchiopexy to bring the testis into the scrotum is the standard treatment. However, the evidence for benefits of early orchiopexy for testicular endocrine function is controversial. The hormonal treatments using human chorionic gonadotropin (hCG) or gonadotropin-releasing hormone (GnRH) to induce testicular descent have low success rates, and therefore they are not recommended by the current guidelines for management of cryptorchidism. However, more research is needed to assess the effects of hormonal treatments during infancy on future male reproductive health.

Inhibin B in healthy and cryptorchid boys

Background

Cryptorchidism, the most common male genital abnormality observed in paediatrics, might often be associated with long-term functional consequences and can even reoccur after a successful orchidopexy. Serum markers that identify cryptorchid boys with gonadal dysfunction early should be useful in a decision-making process. Inhibin B, produced during all of childhood but altered in cryptorchid subjects, appears strictly related to Sertoli cells, and its levels directly reflect the status of the testis germinative epithelium. Unfortunately, its precise roles in bilateral and unilateral cryptorchidism are still debated and being unravelled. Herein, we report the most current knowledge about inhibin B in both healthy boys and those with cryptorchidism to discuss and clarify its potential clinical applications.

Discussion

Inhibin B represents a simple and repeatable serum marker and it seems to well asses the presence and function of the testicular tissue. Testicular tissue in prepubertal age is largely made up of Sertoli cells; inhibin B, coming from working Sertoli cells, allows to indirectly evaluate their function. Besides, inhibin B is produced throughout childhood, even before puberty, in contrast with central hormones, and it is not influenced by androgens during puberty, in contrast with other testicular hormones. Although further studies are needed, low levels of inhibin B have been related with low testicular score and/or with consistent alterations of testicular parameters at histological examination. This means that inhibin B could be an indirect marker of testicular functions that could even replace testicular biopsies, but current data are inconsistent to confirm this potential role of inhibin B in cryptorchidism.

Conclusion

Inhibin B represents an effective candidate for early identification of testicular dysfunction after orchidopexy for cryptorchidism. Unfortunately, current data cannot exactly clarify the real role of inhibin B as a predictor of future testicular function in cryptorchidism and future long-term follow-up studies, with repeated inhibin B checks both in cryptorchid and in formerly cryptorchid children and adolescents, will permit to assess if previous normal levels of inhibin B would match with future normal pubertal development and fertility potential.

Vitamin D status and its relation to exercise performance and iron status in young ice hockey players

Objectives

The aim was to examine the association between serum vitamin D concentration and isometric strength of various muscle groups, vertical jump performance, and repeated sprint ability in young ice hockey players. The secondary aim was to determine the association between vitamin D deficiency and indices of iron status.

Methods

Fifty male ice hockey players (17.2±0.9 years) participated in this cross-sectional study. Exercise performance was evaluated using isometric strength measures of upper and lower extremities, vertical jump performance and repeated sprint ability (RSA). Blood samples were collected for the determination of serum 25-hydroxyvitamin D (25(OH)D) and multiple indicies of iron status.

Results

The mean serum 25(OH)D concentration was 30.4 ng·ml^-1 and ranged from 12.5 to 91.4 ng·ml^-1. Eleven participants (22%) had vitamin D deficiency and 20 athletes (40%) had vitamin D insufficiency. Serum 25(OH)D concentration was not positively correlated with isometric muscle strength, vertical jump performance, or RSA after adjusting for age, training experience, fat mass, fat free mass and height. Serum 25(OH)D concentration was not associated with indices of iron status.

Conclusion

Vitamin D insufficiency is highly prevalent in ice hockey players, but 25(OH)D concentration but it is not associated with exercise performance or indices of iron status.

Association between vitamin D status and testosterone and cortisol in ice hockey players

The identification of the vitamin D receptor in tissues related to testosterone and cortisol production, in conjunction with the observed correlations between vitamin D levels and these hormones in the general population, suggest vitamin D may influence testosterone and cortisol concentrations in athletes. A cross-sectional study design was used to evaluate the association between 25(OH)D and testosterone and cortisol concentrations in young male ice hockey players (n = 50). All athletes were recruited during October from the Sosnowiec area, Poland (50° N). Commercially available ELISA kits were used to determine total serum 25(OH)D, testosterone and cortisol concentrations. Serum 25(OH)D concentration was analyzed as both a continuous and dichotomous variable, binned at the criteria for deficiency (< 20 ng·ml^-1), to investigate a threshold effect. Neither continuous (r = 0.18, p = 0.20) nor dichotomous (r = 0.16, p = 0.27) 25(OH)D concentration was significantly correlated with testosterone concentration. A small, inverse correlation (r = -0.30, p = 0.04) was detected between 25(OH)D and cortisol concentrations when analyzed as a dichotomous variable only. Serum 25(OH)D concentration was neither associated with testosterone (p = 0.09) nor cortisol concentrations (p = 0.11) after adjusting for age, fat free mass and fat mass in sequential linear regression. The inability of vitamin D status to independently predict testosterone and cortisol concentrations suggests that any performance-enhancing effects of vitamin D in athletes are unlikely to be mediated primarily through these hormones, at least amongst young male ice-hockey players.

Age-related testosterone declines can be detected in men's fingernails

Testosterone plays multiple roles in the regulation of development, physiology, reproduction, and behavior. Age-related testosterone declines are expected in the population. However, measuring circulating testosterone is especially challenging because concentrations are labile, responding to social situations and challenges. Matrices that integrate long-term testosterone levels are therefore valuable as biomarkers of endogenous levels as well as chronic exposures. Here, we report on a simple method to extract and measure accumulated testosterone from human fingernails using commercial enzyme immunoassay kits. Furthermore, we demonstrate known human testosterone sex and age trends. Our method is especially useful for quantifying testosterone in men's nails, where a small amount of matrix is required. Thus, this approach is a potential tool for biomonitoring endogenous as well as exogenous testosterone exposure. We suggest considering nails as an alternative matrix for quantifying other steroids as well.

Validity of Self-Assessed Sexual Maturation Against Physician Assessments and Hormone Levels

OBJECTIVE

To compare self-report and physician assessments of sexual maturation against serum hormone markers to evaluate the hypothesis that the validity of self-assessed sexual maturation is underestimated in traditional validation studies.

STUDY DESIGN

We adapted a self-assessment instrument that 248 Mexican children and adolescents, aged 8-13 years, completed. The participants were examined by a trained pediatrician and provided fasting blood samples for measurement of reproductive hormones (eg, testosterone, estradiol, sex hormone-binding globulin, inhibin B) and other hormones (eg, C-peptide, insulin-like growth factor 1, leptin, dehydroepiandrosterone sulfate) known to change during adolescence. Spearman correlations (r) were calculated among the average rank of all hormones and self-assessed and physician-assessed Tanner stage. The method of triads was used to assess the validity of self-reports by estimating correlations between self-assessments and true but unobservable sexual maturation based on all available data. Bootstrap sampling was used to construct 95% CIs.

RESULTS

The validity of self-reported genitalia staging for boys was modest (r = 0.50; 95% CI,  0.31-0.65) and inferior to physician assessment (r = 0.75; 95% CI, 0.56-0.93). Breast stage was well reported (r = 0.89; 95% CI, 0.79-0.97) and superior to physician assessment (r = 0.80; 95% CI, 0.70-0.89). Pubic hair stage reported by boys (r = 0.91; 95% CI, 0.79-0.99) and girls (r = 0.99; 95% CI, 0.96-1.00) was superior to physician assessment (r = 0.79; 95% CI, 0.57-0.97 and r = 0.91; 95% CI, 0.83-0.97, respectively).

CONCLUSION

Self-assessment can be validly used in epidemiologic studies for evaluating sexual maturation in children; however, physician assessment may be necessary for accurate assessment of genitalia development in boys.

Familial forms of disorders of sex development may be common if infertility is considered a comorbidity

BACKGROUND

Families with 46,XY Disorders of Sex Development (DSD) have been reported, but they are considered to be exceptionally rare, with the exception of the familial forms of disorders affecting androgen synthesis or action. The families of some patients with anorchia may include individuals with 46,XY gonadal dysgenesis. We therefore analysed a large series of patients with 46,XY DSD or anorchia for the occurrence in their family of one of these phenotypes and/or ovarian insufficiency and/or infertility and/or cryptorchidism.

METHODS

A retrospective study chart review was performed for 114 patients with 46,XY DSD and 26 patients with 46,XY bilateral anorchia examined at a single institution over a 33 year period.

RESULTS

Of the 140 patients, 25 probands with DSD belonged to 21 families and 7 with anorchia belonged to 7 families. Familial forms represent 22% (25/114) of the 46,XY DSD and 27% (7/26) of the anorchia cases. No case had disorders affecting androgen synthesis or action or 5 α-reductase deficiency. The presenting symptom was genital ambiguity (n = 12), hypospadias (n = 11) or discordance between 46,XY karyotyping performed in utero to exclude trisomy and female external genitalia (n = 2) or anorchia (n = 7). Other familial affected individuals presented with DSD and/or premature menopause (4 families) or male infertility (4 families) and/or cryptorchidism. In four families mutations were identified in the genes SRY, NR5A1, GATA4 and FOG2/ZFPM2. Surgery discovered dysgerminoma or gonadoblastoma in two cases with gonadal dysgenesis.

CONCLUSIONS

This study reveals a surprisingly high frequency of familial forms of 46,XY DSD and anorchia when premature menopause or male factor infertility are included. It also demonstrates the variability of the expression of the phenotype within the families. It highlights the need to the physician to take a full family history including fertility status. This could be important to identify familial cases, understand modes of transmission of the phenotype and eventually understand the genetic factors that are involved.

Anthropometric Measurements, Serum Reproductive Hormonal Levels and Sexual Development among Boys in the Rural Western Cape, South Africa

Data on growth and sexual maturation among boys from the rural Western Cape in South Africa is limited. A cross-sectional study of 269 school boys was conducted testing for serum luteinizing hormone (LH), follicle stimulating hormone (FSH), testosterone, sex hormone binding globulin (SHBG) and estradiol (E2); height, weight and body mass index (BMI); sexual maturity (using Tanner Stages) and a questionnaire (demographic and medical history). The median age at pubertal onset (Tanner Stage 2) and Tanner Stage 5 was 11.6 and 14.7 years, respectively. The median testicular volume was 5.5 mL at Tanner Stage 2 increasing from 2.5 mL at Tanner Stage 1 to 14.7 mL at Tanner Stage 5. Height and weight measurements were <25th & 50th percentile references at Tanner Stages 1–3. Controlling for confounders, serum FSH and LH increased (p < 0.05) from Tanner Stage 1 to 4 (by 4.1 and 3 mL respectively), and serum testosterone and estradiol increased after Tanner Stage 2 (by 12.7 nmol/L and 59.5 pmol/L respectively). These results indicate some delays in pubertal development of boys in the rural Western Cape when compared to boys from other settings possibly due to nutritional, socio-economic and environmental exposures. Changes in serum hormone levels were consistent with other populations. Initiatives to improve nutrition amongst Western Cape rural communities are recommended.

A Normative Model of Serum Inhibin B in Young Males

Inhibin B has been identified as a potential marker of Sertoli cell function in males. The aim of this study is to produce a normative model of serum inhibin B in males from birth to seventeen years. We used a well-defined search strategy to identify studies containing data that can contribute to a larger approximation of the healthy population. We combined data from four published studies (n = 709) and derived an internally validated model with high goodness-of-fit and normally distributed residuals. Our results show that inhibin B increases following birth to a post-natal peak of 270 pg/mL (IQR 210-335 pg/mL) and then decreases during childhood followed by a rise at around 8 years, peaking at a mean 305 pg/mL (IQR 240-445 pg/mL) at around age 17. Following this peak there is a slow decline to the standard mature adult normal range of 170 pg/mL (IQR 125-215 pg/mL). This normative model suggests that 35% of the variation in Inhibin B levels in young males is due to age alone, provides an age-specific reference range for inhibin B in the young healthy male population, and will be a powerful tool in evaluating the potential of inhibin B as a marker of Sertoli cell function in pre-pubertal boys.

IGSF1 Deficiency: Lessons From an Extensive Case Series and Recommendations for Clinical Management

CONTEXT

Mutations in the immunoglobulin superfamily, member 1 (IGSF1) gene cause the X-linked IGSF1 deficiency syndrome consisting of central hypothyroidism, delayed pubertal testosterone rise, adult macroorchidism, variable prolactin deficiency, and occasionally transient partial GH deficiency. Since our first reports, we discovered 20 new families with 18 new pathogenic IGSF1 mutations.

OBJECTIVE

We aimed to share data on the largest cohort of patients with IGSF1 deficiency to date and formulate recommendations for clinical management.

METHODS

We collected clinical and biochemical characteristics of 69 male patients (35 children, 34 adults) and 56 female IGSF1 mutation carriers (three children, 53 adults) from 30 unrelated families according to a standardized clinical protocol. At evaluation, boys were treated with levothyroxine in 89%, adult males in 44%, and females in 5% of cases.

RESULTS

Additional symptoms in male patients included small thyroid gland volume (74%), high birth weight (25%), and large head circumference (20%). In general, the timing of pubertal testicular growth was normal or even premature, in contrast to a late rise in T levels. Late adrenarche was observed in patients with prolactin deficiency, and adult dehydroepiandrosterone concentrations were decreased in 40%. Hypocortisolism was observed in 6 of 28 evaluated newborns, although cortisol concentrations were normal later. Waist circumference of male patients was increased in 60%, but blood lipids were normal. Female carriers showed low free T4 (FT4) and low-normal FT4 in 18% and 60%, respectively, delayed age at menarche in 31%, mild prolactin deficiency in 22%, increased waist circumference in 57%, and a negative correlation between FT4 concentrations and metabolic parameters.

CONCLUSION

IGSF1 deficiency represents the most common genetic cause of central hypothyroidism and is associated with multiple other characteristics. Based on these results, we provide recommendations for mutational analysis, endocrine work-up, and long-term care.

Congenital Hypogonadotropic Hypogonadism and Kallmann Syndrome: Past, Present, and Future

The proper development and coordination of the hypothalamic-pituitary-gonadal (HPG) axis are essential for normal reproductive competence. The key factor that regulates the function of the HPG axis is gonadotrophin-releasing hormone (GnRH). Timely release of GnRH is critical for the onset of puberty and subsequent sexual maturation. Misregulation in this system can result in delayed or absent puberty and infertility. Congenital hypogonadotropic hypogonadism (CHH) and Kallmann syndrome (KS) are genetic disorders that are rooted in a GnRH deficiency but often accompanied by a variety of non-reproductive phenotypes such as the loss of the sense of smell and defects of the skeleton, eye, ear, kidney, and heart. Recent progress in DNA sequencing technology has produced a wealth of information regarding the genetic makeup of CHH and KS patients and revealed the resilient yet complex nature of the human reproductive neuroendocrine system. Further research on the molecular basis of the disease and the diverse signal pathways involved will aid in improving the diagnosis, treatment, and management of CHH and KS patients as well as in developing more precise genetic screening and counseling regime.

Expert consensus document: European Consensus Statement on congenital hypogonadotropic hypogonadism--pathogenesis, diagnosis and treatment

Congenital hypogonadotropic hypogonadism (CHH) is a rare disorder caused by the deficient production, secretion or action of gonadotropin-releasing hormone (GnRH), which is the master hormone regulating the reproductive axis. CHH is clinically and genetically heterogeneous, with >25 different causal genes identified to date. Clinically, the disorder is characterized by an absence of puberty and infertility. The association of CHH with a defective sense of smell (anosmia or hyposmia), which is found in ∼50% of patients with CHH is termed Kallmann syndrome and results from incomplete embryonic migration of GnRH-synthesizing neurons. CHH can be challenging to diagnose, particularly when attempting to differentiate it from constitutional delay of puberty. A timely diagnosis and treatment to induce puberty can be beneficial for sexual, bone and metabolic health, and might help minimize some of the psychological effects of CHH. In most cases, fertility can be induced using specialized treatment regimens and several predictors of outcome have been identified. Patients typically require lifelong treatment, yet ∼10-20% of patients exhibit a spontaneous recovery of reproductive function. This Consensus Statement summarizes approaches for the diagnosis and treatment of CHH and discusses important unanswered questions in the field.

Impact of varicocele on biological markers of gonadal function

PURPOSE

The aim of this study is to evaluate the potential effect of varicocele in the hormonal and clinical profile of adolescents.

METHODS

Twenty adolescents at Tanner stage 4-5 with left varicocele were studied and compared with a control group of 20 healthy adolescents. All patients underwent ultrasonographic testicular volumetry as well as hormonal evaluation of inhibin B, testosterone, baseline and gonadotropin-releasing hormone stimulated, follicle-stimulating hormone as well as luteinizing hormone. Statistical analysis was performed using the student's t test with p value <0.05 taken as statistical significant.

RESULTS

Patients with varicocele showed reduced levels of inhibin B compared to controls and a significant reduction in the testicular volume on the affected side. The response of luteinizing hormone to gonadotropin-releasing hormone stimulation was significantly higher in the varicocele group compared to the control group. Furthermore a significant inverse relationship of inhibin B compared to follicle-stimulating hormone was noted.

CONCLUSION

Serum inhibin B levels could represent a useful marker of Sertoli cell damage caused by varicocele.

Male germ cell development in humans

BACKGROUND

Germ cells are unique cells that possess the ability to transmit genetic information between generations. Detailed knowledge about the molecular and cellular mechanisms determining the fate of human male germ cells still remains sparse. This is partially due to ethical issues limiting the access to research material. Therefore, the mechanisms of proliferation, differentiation and apoptosis of human male germ cells still remain challenging study objectives.

METHODS

This review focuses on using English articles accessible in PubMed as well as personal files on the current knowledge of the molecular and cellular mechanisms connected with human testicular germ cell development, maturation failure and the possibility of fertility preservation in patients in whom there is a risk of gonadal failure. However, since rodents, particularly mice, offer the possibility of studying germ cell development by use of genetic modification techniques, some studies using animal models are also discussed.

CONCLUSION

This mini review focuses on the current knowledge about male germ cells. However, the reader is referred to two previous mini reviews focusing on testicular somatic cells, i.e. on Sertoli cells and Leydig cells.

High Doses of Caffeine during the Peripubertal Period in the Rat Impair the Growth and Function of the Testis

Prenatal caffeine exposure adversely affects the development of the reproductive organs of male rat offspring. Thus, it is conceivable that peripubertal caffeine exposure would also influence physiologic gonadal changes and function during this critical period for sexual maturation. This study investigated the impact of high doses of caffeine on the testes of prepubertal male rats. A total of 45 immature male rats were divided randomly into three groups: a control group and 2 groups fed 120 and 180 mg/kg/day of caffeine, respectively, via the stomach for 4 weeks. Caffeine caused a significant decrease in body weight gain, accompanied by proportional decreases in lean body mass and body fat. The caffeine-fed animals had smaller and lighter testes than those of the control that were accompanied by negative influences on the histologic parameters of the testes. In addition, stimulated-testosterone ex vivo production was reduced in Leydig cells retrieved from the caffeine-fed animals. Our results demonstrate that peripubertal caffeine consumption can interfere with the maturation and function of the testis, possibly by interrupting endogenous testosterone secretion and reducing the sensitivity of Leydig cells to gonadotrophic stimulation. In addition, we confirmed that pubertal administration of caffeine reduced testis growth and altered testis histomorphology.

The gonadal function in obese adolescents: review

This review deals with the relationship between obesity in male adolescents and gonadal function. The article is structured in two main paragraphs; the first one is about population studies that have assessed puberty timing and its mode of onset in relation with body weight to evaluate if and how the latter can influence the gonadal function in this phase of life. These studies analyze issues such as increased BMI and early onset of male puberty, gender differences, secular trend toward early onset of puberty in males, effects of a different body composition on male puberty and consequences of a different stage of childhood obesity on the onset of male puberty. The second paragraph examines the possible mechanisms through which, obesity may alter the timing of puberty in young males, including the role of SHBG, leptin, insulin resistance, ghrelin, GH-IGF-1 axis, AR polymorphisms, primary testicular dysfunction, retinol binding protein 4 (RBP-4) and liver function abnormalities. However, despite the numerous studies in the literature, the etiology of gonadal disfunction in obese adolescents on puberty remains uncertain.

A randomized controlled trial on a multicomponent intervention for overweight school-aged children - Copenhagen, Denmark

Background

Obesity amongst children is a growing problem worldwide. In contrast to adults, little is known on the effects of controlled weight loss on components of the metabolic syndrome in children. The primary aim of the study was to evaluate the effects of a 20-week exercise and diet guidance intervention on body mass index (BMI) in a group of overweight children. Our hypothesis was an observed reduction in BMI and secondarily in body fat content, insulin insensitivity, and other components of the metabolic syndrome in the intervention group.

Methods

School children from Copenhagen were randomly allocated to an intervention group (n = 19) or a control group (n = 19). Anthropometric assessment, whole body dual-energy X-ray absorptiometry scan, two hours oral glucose tolerance test, steps measured by pedometer, and fitness tests were measured at baseline and at 20 weeks.

Results

Thirty-seven children (30 girls) participated at baseline, aged 8.7 ± 0.9 years with a BMI of 21.8 ± 3.7 kg/m² (mean ± SD), and 36 children completed the study. The intervention group decreased their BMI (the intervention effect is the difference in change between the groups adjusted for the respective baseline values (DELTA) = -2.0 kg/m², 95% CI: -2.5; -1.5, P <0.001), total body mass (DELTA = -4.0 kg, 95% CI: -4.9; -3.0, P <0.001), and fat mass (DELTA = -3.3 kg, 95% CI: -4.2; -2.7, P <0.001) compared to the control group after the intervention. The intervention group displayed decreased waist, hip and waist-to-height ratio (WHtR) (all three variables; P <0.001), area under curve for plasma insulin (P <0.05), and increased mean and minimum steps/day (P <0.05 and P <0.01, respectively).

Conclusions

The multicomponent intervention had significant favorable effects on BMI, weight, WHtR, mean and minimum steps/day, and fat mass. In addition, similar beneficial metabolic effects were found in the children as shown in adults, e.g. increase in peripheral insulin sensitivity.

Trial registration

Clinicaltrials.gov Identifier number NCT01660789.

Could androgen receptor gene CAG tract polymorphism affect spermatogenesis in men with idiopathic infertility?

PURPOSE

This study examined whether the AR-CAG repeat length might affect clinical characteristics (testis volume) seminal parameters (sperm count and its mobility) along with hormonal serum profile [FSH, LH, Testosterone (T) and Inhibin B (InhB)] both in idiopathic male infertility (IM) and in infertility due to a previous condition of cryptorchidism (CryM) or to Y chromosome long arm microdeletions (YM).

DESIGN

Observational study without intervention(s).

PATIENTS

One hundred and ten IM patients [90 idiopathic olizoospermic males (IOM) and 20 idiopathic azoospermic males (IAM)], 19 CryM male and 10 YM patients were included. Sixty-one age-matched healthy men who had fathered within 3 years were involved representing the control group (FM).

RESULTS

AR-CAG repeats stretch was significantly longer in IOM (p<0.05), CryM (p<0.05) and YM (p<0.001) than FM. When the AR-CAG repeat tracts were subdivided in three subgroups according to the length of CAG repeats tract assessed in fertile subjects (the one with the middle (n 19-21) belonging to the 25 and 75 % inter-quartile, the ends belonging to the <25 % inter-quartile and >75 % inter-quartile, respectively), there was a statistically significant difference of distribution of AR-CAG tract length among fertile and different groups of infertile men (p=<0.0005; chi-square test). Moreover, the subgroup of AR-CAG repeat stretch with 22-28 triplets was associated with lower levels of InhB both in idiopathic oligozoospermic (Scheffe, Bonferroni and Dunett tests p=<0.01) and azoospermic men (Scheffe, Bonferroni and Dunett test p=<0.05), while, when FM and men with idiopathic infertility were gathered in a single group, both the subgroup of AR- CAG tract with 15-18 repeats and the one with 22-28 repeats are associated with lower testis volume, reduced sperm count and serum InhB levels.

CONCLUSIONS

Our study showed that the outliers of AR-CAG repeat length seem to influence the function of AR, affecting testis volume and Sertoli cell function and consequently sperm production in both fertile and idiopathic infertile men.

Precocious initiation of spermatogenesis in a 19-month-old boy with Hurler syndrome

Mucopolysaccharidosis type IH (MPS IH) is a rare autosomal recessive lysosomal storage disorder. Haematopoietic stem cell transplantation (HSCT) has been proposed for the treatment of MPS IH patients and offers the possibility to grow into their adulthood. Precocious puberty has been described in few MPS patients. We report, to the best of our knowledge and for the first time, the initiation of the first waves of spermatogenesis fortuitously observed in seminiferous tubules of a pre-pubertal 19-month-old boy, affected by MPS IH and who did not present any clinical signs of precocious puberty. This patient benefited from testicular tissue cryopreservation before HSCT. Seminiferous tubule size, germ cell differentiation and Sertoli cell expression of androgen receptor and anti-müllerian hormone corresponded to the pattern observed in a pubertal boy. The Hurler syndrome may be responsible for the precocious initiation of spermatogenesis. A specific follow-up during childhood may be useful to confirm if such abnormal testis development is common in young boys with MPS IH and if it may lead to precocious onset of puberty in survivors despite HSCT. Furthermore, we have observed that Sertoli cell maturation (up-regulation of AR expression, down-regulation of AMH expression) occurred before the clinical signs of puberty and before the increase of testosterone plasmatic level.

Congenital hypogonadotropic hypogonadism during childhood: presentation and genetic analyses in 46 boys

BACKGROUND

The majority of the patients reported with mutations in isolated hypogonadotropic hypogonadism (HH) are adults. We analysed the presentation and the plasma inhibin B and anti-müllerian hormone (AMH) concentrations during childhood and adolescence, and compared them to the genetic results.

METHODS

This was a retrospective, single-center study of 46 boys with HH.

RESULTS

Fourteen (30.4%) had Kallmann syndrome (KS), 4 (8.7%) had CHARGE syndrome and 28 (60.9%) had HH without olfaction deficit nor olfactive bulb hypoplasia. Eighteen (39%) had an associated malformation or syndromes. At diagnosis, 22 (47.8%) boys were aged <one year, 9 (19%) 1-11 and 15 (32.6%) 11-17.6 years. They presented with micropenis (n = 32, 69.6%, including all those <one year), cryptorchidism (n = 32, 69.6%, unilateral in 8, bilateral in 24), and/or pubertal delay (n = 11). The plasma inhibin B concentrations were normal in 8 (3 KS including one CHARGE and 5 other HH), at the lower limit of the normal in 6 and decreased in 13 (48%) boys. The AMH concentrations were normal in 15 (6 KS including one CHARGE and 9 other HH) and decreased in 12 (44%) boys. In addition to the CHD7 gene mutations in 4 patients with CHARGE, mutations were found in 5/26 other boys analysed including one in KAL1 gene with STS, 2 in FGFR1 gene, one in PROKR2 gene and one in GnRHR gene.

CONCLUSIONS

The presence of micropenis in neonate, particularly if associated with cryptorchidism, is an indication to look for gonadotropin deficiency isolated or associated with other hypothalamic-pituitary deficiencies. Inhibin B and AMH concentrations are suggestive if low, but they may be normal. Despite the high frequency of the associated malformations and excluding the patients with CHARGE or ichtyosis, the 4 patients with mutations had no family history or malformation. This suggests that many other genes are involved.

SOT Symposium Highlight: Translatable Indicators of Testicular Toxicity: Inhibin B, MicroRNAs, and Sperm Signatures

Testicular toxicity is an important safety endpoint in drug development and risk assessment, but reliable and translatable biomarkers for predicting injury have eluded researchers. However, this area shows great potential for improvement, with several avenues currently being pursued. This was the topic of a symposium session during the 2013 Society of Toxicology Annual Meeting in San Antonio, TX, entitled "Translatable Indicators of Testicular Toxicity: Inhibin B, MicroRNAs, and Sperm Signatures." This symposium brought together stakeholders from academia, government, and industry to present the limitations and drawbacks of currently used indicators of injury and discussed the ongoing efforts in developing more predictive biomarkers of injury. The presentations highlighted the early challenges of using circulating inhibin B and microRNA levels, and sperm messenger RNA transcript abundance and DNA methylation profiles, as novel biomarkers of testicular toxicity.

Reproductive hormone profile and pubertal development in 14-year-old boys prenatally exposed to polychlorinated biphenyls

Because polychlorinated biphenyls (PCBs) are thought to cause endocrine disruption, we examined 438 adolescent boys from a birth cohort in the Faroe Islands, where PCB exposures are elevated. We measured PCBs and p,p'-dichlorodiphenyldichloroethylene (DDE) in cord blood and in serum from clinical examination at age 14. Higher prenatal PCB exposure was associated with lower serum concentrations of both luteinizing hormone (LH) and testosterone. In addition, sex hormone binding globulin (SHBG) was positively associated with both prenatal and concurrent PCB exposures. The PCB-SHBG association was robust to covariate adjustment. In a structural equation model, a doubling in prenatal PCB exposure was associated with a decrease in LH of 6% (p=0.03). Prenatal exposure to PCB and DDE showed weak, non-significant inverse associations with testicular size and Tanner stage. DDE was highly correlated with PCB and showed slightly weaker associations with the hormone profile. These findings suggest that delayed puberty with low serum-LH concentrations associated with developmental exposure to non dioxin-like PCBs may be due to a central hypothalamo-pituitary mechanism.

Inhibin B and anti-Müllerian hormone/Müllerian-inhibiting substance may contribute to the male bias in autism

The autistic spectrum disorders have a significant male bias in incidence, which is unexplained. The Sertoli cells of the immature testes secrete supra-adult levels of Müllerian-inhibiting substance/anti-Müllerian hormone (AMH) and inhibin B (InhB), with both hormones being putative regulators of brain development. We report here, that 82 boys with an autism spectrum disorder have normal levels of InhB and AMH. However, the boys' level of InhB correlated with their autism diagnostic interview-revised (ADI-R) scores for the social interaction (R=0.29, P=0.009, N=82) and communication domains (R=0.29, P=0.022, N=63), and with the number of autistic traits the boys exhibited (R=0.34 and 0.27, respectively). The strengths of the abovementioned correlates were stronger in the boys with milder autism (R=0.42 and 0.50, respectively), with AMH exhibiting a significant negative correlation to the ADI-R score in these boys (R=-0.44 and R=-0.39, respectively). Neither hormone correlated to the incidence of stereotyped and repetitive behaviours. This suggests that the male bias in the autistic spectrum has multiple determinants, which modulate the effects of an otherwise non-dimorphic pathology. Furthermore, AMH and InhB have opposing effects on the SMAD1/5/8 pathway, and opposing correlates to autistic traits, implicating the SMAD pathways as a putative point of molecular convergence for the autistic spectrum.

Longitudinal evaluation of the hypothalamic-pituitary-testicular function in 8 boys with adrenal hypoplasia congenita (AHC) due to NR0B1 mutations

Background

Boys carrying mutations in the NR0B1 gene develop adrenal hypoplasia congenita (AHC) and impaired sexual development due to the combination of hypogonadotropic hypogonadism (HH) and primary defects in spermatogenesis.

Methods

We analysed the evolution of hypothalamic-pituitary-testicular function of 8 boys with AHC due to NR0B1 mutations. Our objective was to characterize and monitor the progressive deterioration of this function.

Results

The first symptoms appeared in the neonatal period (n = 5) or between 6 months and 8.7 years (n = 3). Basal plasma adrenocorticotrophic hormone (ACTH) concentrations increased in all boys, whilst cortisol levels decreased in one case. The natremia was equal or below 134 mmol/L and kaliemia was over 5 mmol/L. All had increased plasma renin. In 3 of 4 patients diagnosed in the neonatal period and evaluated during the first year, the basal plasma gonadotropins concentrations, and their response to gonadotropin releasing hormone (GnRH) test (n = 2), and those of testosterone were normal. The plasma inhibin B levels were normal in the first year of life. With the exception of two cases these concentrations decreased to below the normal for age. Anti-Müllerian hormone concentrations were normal for age in all except one case, which had low concentrations before the initiation of testosterone treatment. In 3 of the 8 cases the gene was deleted and the remaining 5 cases carried frameshift mutations that are predicted to introduce a downstream nonsense mutation resulting in a truncated protein.

Conclusions

The decreases in testosterone and inhibin B levels indicated a progressive loss of testicular function in boys carrying NR0B1 mutations. These non-invasive examinations can help to estimate the age of the testicular degradation and cryopreservation of semen may be considered in these cases as investigational procedure with the aim of restoring fertility.

The FSH-inhibin axis in prader-willi syndrome: heterogeneity of gonadal dysfunction

BACKGROUND

We characterized the spectrum and etiology of hypogonadism in a cohort of Prader-Willi syndrome (PWS) adolescents and adults.

METHODS

Reproductive hormonal profiles and physical examination were performed on 19 males and 16 females ages 16-34 years with PWS. Gonadotropins, sex-steroids, inhibin B (INB) and anti-Mullerian hormone (AMH) were measured. We defined 4 groups according to the relative contribution of central and gonadal dysfunction based on FSH and INB levels: Group A: primary hypogonadism (FSH >15 IU/l and undetectable INB (<10 pg/ml); Group B: central hypogonadism (FSH <0.5 IU/l, INB <10 pg/ml); Group C: partial gonadal & central dysfunction (FSH 1.5-15 IU/l, INB >20 pg/ml); Group D: mild central and severe gonadal dysfunction (FSH 1.5-15 IU/l, INB < 10 pg/ml.

RESULTS

There were 10, 8, 9 and 8 individuals in Groups A-D respectively; significantly more males in group A (9, 4, 4 and 2; P = 0.04). Significant differences between the groups were found in mean testosterone (P = 0.04), AMH (P = 0.003) and pubic hair (P = 0.04) in males and mean LH (P = 0.003) and breast development (P = 0.04) in females. Mean age, height, weight, BMI and the distribution of genetic subtypes were similar within the groups.

CONCLUSIONS

Analysis of FSH and inhibin B revealed four distinct phenotypes ranging from primary gonadal to central hypogonadism. Primary gonadal dysfunction was common, while severe gonadotropin deficiency was rare. Longitudinal studies are needed to verify whether the individual phenotypes are consistent.

Application of the new classification on patients with a disorder of sex development in indonesia

Disorder of sex development (DSD) patients in Indonesia most often do not receive a proper diagnostic evaluation and treatment. This study intended to categorize 88 Indonesian patients in accordance with the new consensus DSD algorithm. Diagnostic evaluation including clinical, hormonal, genetic, imaging, surgical, and histological parameters was performed. Fifty-three patients were raised as males, and 34 as females. Of 22 patients with 46, XX DSD, 15 had congenital adrenal hyperplasia, while in one patient, an ovarian Leydig cell tumor was found. In all 58 46, XY DSD patients, 29 were suspected of a disorder of androgen action (12 with an androgen receptor mutation), and in 9, gonadal dysgenesis was found and, in 20, severe hypospadias e.c.i. Implementation of the current consensus statement in a resource-poor environment is very difficult. The aim of the diagnostic workup in developing countries should be to end up with an evidence-based diagnosis. This is essential to improve treatment and thereby to improve the patients' quality of life.

Mutation analysis of NR5A1 encoding steroidogenic factor 1 in 77 patients with 46, XY disorders of sex development (DSD) including hypospadias

Background

Mutations of the NR5A1 gene encoding steroidogenic factor-1 have been reported in association with a wide spectrum of 46,XY DSD (Disorder of Sex Development) phenotypes including severe forms of hypospadias.

Methodology/Principal Findings

We evaluated the frequency of NR5A1 gene mutations in a large series of patients presenting with 46,XY DSD and hypospadias. Based on their clinical presentation 77 patients were classified either as complete or partial gonadal dysgenesis (uterus seen at genitography and/or surgery, n = 11), ambiguous external genitalia without uterus (n = 33) or hypospadias (n = 33). We identified heterozygous NR5A1 mutations in 4 cases of ambiguous external genitalia without uterus (12.1%; p.Trp279Arg, pArg39Pro, c.390delG, c140_141insCACG) and a de novo missense mutation in one case with distal hypospadias (3%; p.Arg313Cys). Mutant proteins showed reduced transactivation activity and mutants p.Arg39Pro and p.Arg313Cys did not synergize with the GATA4 cofactor to stimulate reporter gene activity, although they retained their ability to physically interact with the GATA4 protein.

Conclusions/Significance

Mutations in NR5A1 were observed in 5/77 (6.5%) cases of 46,XY DSD including hypospadias. Excluding the cases of 46,XY gonadal dysgenesis the incidence of NR5A1 mutations was 5/66 (7.6%). An individual with isolated distal hypopadias carried a de novo heterozygous missense mutation, thus extending the range of phenotypes associated with NR5A1 mutations and suggesting that this group of patients should be screened for NR5A1 mutations.

Serum inhibin B levels before and after varicocelectomy in early adolescence

BACKGROUND

Whereas no clear relationship has been observed between varicocelectomy and serum inhibin B levels in men, in adolescents comparison between inhibin B levels before and after varicocelectomy is lacking.

AIM

To evaluate the effect of varicocele surgical treatment on inhibin B levels in adolescents at the beginning of puberty compared to a group of healthy adolescents.

SUBJECTS AND METHODS

We studied 28 adolescents in Tanner 2 pubertal stage with a grade III left-sided varicocele (patients) compared to 13 age and pubertal stage-matched healthy adolescents (controls). All patients underwent blood tests to determine serum inhibin B levels before and 6 months after varicocelectomy by Palomo procedure. For comparison we investigated inhibin B levels in controls and repeated this test 6 months later. Testicular ultrasound was performed for patients only.

RESULTS

Baseline inhibin B concentrations of patients and controls were 109.90 ± 40.26 and 109.33 ± 38.34 pg/ml, respectively. No significant changes were observed in patients' inhibin B concentrations after varicocelectomy (116.00 ± 42.65 pg/ml), or in controls during the 6 months' follow-up (99.12 ± 30.09 pg/ml). Doppler examination after treatment shows a complete resolution of varicocele in all the patients without alterations in testicular parenchyma.

CONCLUSIONS

Varicocelectomy performed on adolescents at T2 pubertal stage might be useful to avoid alteration in inhibin B production and consequently in testicular function. Further studies are necessary to confirm the prognostic value of inhibin B levels and the benefit of early varicocelectomy in preserving the fertility of these adolescents.

Associations between testicular hormones at adolescence and attendance at chlorinated swimming pools during childhood

The goal was to evaluate the associations between testicular hormones at adolescence and the exposure to chlorination by-products when attending chlorinated swimming pools. We obtained serum samples from 361 school male adolescents (aged 14–18 years) who had visited swimming pools disinfected with chlorine or by copper–silver ionization. We analysed serum concentrations of inhibin B (two different assays), total and free testosterone, sex hormone-binding globulin, luteinizing hormone (LH), follicle stimulating hormone (FSH) and dehydroepiandrosterone sulphate (DHEAS). There were strong inverse associations between serum levels of inhibin B (both assays) or of total testosterone, adjusted or unadjusted for gonadotropins and the time adolescents had spent in indoor chlorinated pools, especially during their childhood. Adolescents having attended indoor chlorinated pools for more than 250 h before the age of 10 years or for more than 125 h before the age of 7 years were about three times more likely to have an abnormally low serum inhibin B and/or total testosterone (<10th percentile) than their peers who never visited this type of pool during their childhood (odds ratio, 95% CI, 2.83, 1.06–7.52, p = 0.04 and 3.67, 1.45–9.34, p = 0.006, respectively). Such associations were not seen with free testosterone, LH, FSH and DHEAS or with the attendance of outdoor chlorinated pools or of the copper–silver pool. Swimming in indoor chlorinated pools during childhood is strongly associated with lower levels of serum inhibin B and total testosterone. The absorption of reprotoxic chlorination by-products across the highly permeable scrotum might explain these associations.

Inhibin B and anti-Müllerian hormone as markers of gonadal function after hematopoietic cell transplantation during childhood

Background

It is difficult to predict the reproductive capacity of children given hematopoietic cell transplantation (HCT) before pubertal age because the plasma concentrations of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) are not informative and no spermogram can be done.

Methods

We classified the gonadal function of 38 boys and 34 girls given HCT during childhood who had reached pubertal age according to their pubertal development and FSH and LH and compared this to their plasma inhibin B and anti-Müllerian hormone (AMH).

Results

Ten (26%) boys had normal testicular function, 16 (42%) had isolated tubular failure and 12 (32%) also had Leydig cell failure. All 16 boys given melphalan had tubular failure. AMH were normal in 25 patients and decreased in 6, all of whom had increased FSH and low inhibin B.

Seven (21%) girls had normal ovarian function, 11 (32%) had partial and 16 (47%) complete ovarian failure. 7/8 girls given busulfan had increased FSH and LH and 7/8 had low inhibin B. AMH indicated that ovarian function was impaired in all girls.

FSH and inhibin B were negatively correlated in boys (P < 0.0001) and girls (P = 0.0006). Neither the age at HCT nor the interval between HCT and evaluation influenced gonadal function.

Conclusion

The concordance between FSH and inhibin B suggests that inhibin B may help in counselling at pubertal age. In boys, AMH were difficult to use as they normally decrease when testosterone increases at puberty. In girls, low AMH suggest that there is major loss of primordial follicles.

Luteinizing hormone, testosterone and inhibin B levels in the peripubertal period and racial/ethnic differences among boys aged 6-11 years: analyses from NHANES III, 1988-1994

OBJECTIVE

To determine whether the initial physical findings of puberty are accompanied by hormonal evidence of pubertal activation of the hypothalamic-pituitary-gonadal (HPG) axis and whether racial/ethnic differences exist, we have analysed hormone levels in relation to age, onset of puberty and race/ethnicity.

DESIGN

Cross-sectional analysis of luteinizing hormone (LH), testosterone (T) and inhibin B from banked sera from a representative sample of US boys aged 6·0-11·99 years who participated in the National Health and Nutrition Examination Survey (NHANES) III.

PATIENTS

Eight hundred and twenty-eight boys having sera including 228 non-Hispanic white (NHW), 266 non-Hispanic black (NHB), 288 Mexican-American (MA) and 46 'other'.

MEASUREMENTS

Using analysis of variance and linear regression techniques, concentrations of LH, T and inhibin B were compared by race/ethnicity for all boys and pubertal status (Tanner's Staging 1, 2 and 3+) for boys aged 8 years and older. Receiver operating curves were utilized to identify cut-points predictive of pubertal HPG status.

RESULTS

Mean hormones levels progressively increased with age. Receiver operating characteristic (ROC) curves indicate hormones are consistent with pubertal onset as indicated by Tanner stage 2, except for T and genital stage 2. Inhibin B and LH levels increased significantly by genital stage after adjusting for age and race/ethnicity, while LH and T concentrations increased significantly across pubic hair stages. Levels of inhibin B were significantly higher for NHB boys compared with other racial/ethnic groups.

CONCLUSIONS

In these cross-sectional findings, hormone levels rise gradually as boys approach the peripubertal age, whereas an abrupt rise was not associated with the onset of physical changes of puberty.

Aromatase deficiency in men: a clinical perspective

Human aromatase deficiency is a very rare syndrome characterized by congenital estrogen deprivation that is caused by loss-of-function mutations in CYP19A1, which encodes aromatase. Here, we review the presentation, diagnosis and treatment of aromatase deficiency in men to provide useful advice for clinical management of the condition. At presentation, all men with aromatase deficiency have tall stature, delayed bone maturation, osteopenia or osteoporosis and eunuchoid skeletal proportions. Diagnosis of the condition is supported by the presence of unfused epiphyses and undetectable serum estradiol levels; the condition can be further substantiated by genetic sequencing of CYP19A1. Transdermal estradiol treatment at a daily dose of about 25 microg might be adequate for lifelong replacement therapy. BMD and levels of serum estradiol, luteinizing hormone and testosterone should be monitored carefully and considered powerful biochemical markers of adequate estrogen substitution in clinical practice. Early diagnosis is important to initiate estrogen therapy as soon after puberty as possible to avoid the skeletal complications that are associated with this condition.

Role of seminiferous tubular development in determining the FSH versus LH responsiveness to GnRH in early sexual maturation

BACKGROUND

The onset of sexual maturation at puberty is a unique developmental period from a neuroendocrine perspective in that it is characterized by enhanced FSH secretion and FSH responsiveness to exogenous GnRH (vs. LH) from the gonadotrope, yet the mechanism of these dynamics remains unclear. This study aimed to elucidate this phenomenon using a human disease model of GnRH deficiency (idiopathic hypogonadotropic hypogonadism, IHH) in which GnRH input can be experimentally controlled.

METHODS

25 GnRH-deficient men were selected for study based upon their baseline testicular volumes (TV) and serum inhibin B (I(B)) levels to represent a spectrum of pubertal/testicular development. Subjects underwent: (i) a 12-hour overnight neuroendocrine evaluation for hormonal profiling and determination of endogenous LH secretion pattern, and (ii) a 7-day exposure to a physiologic regimen of exogenous pulsatile GnRH (25 ng/kg every 2 h). Daily measurements of serum testosterone (T) and I(B) levels were made and a 2-hour window of frequent blood sampling was monitored to measure LH and FSH following a single i.v. GnRH bolus (25 ng/kg). All subjects were screened for known loci underlying GnRH deficiency and the response to GnRH was tracked according to genotype.

RESULTS

Among the entire cohort, no changes were noted in serum T or I(B) during the 7 days, thus keeping gonadal feedback relatively constant. However, serum LH and FSH levels increased significantly (p < 0.0001) in the entire cohort. When analyzed by degree of pubertal/testicular development, men with no evidence of prior spontaneous pubertal development (TV <or=3 ml, Group I) showed sharp increases in serum FSH compared to men with some prior evidence of partial puberty (TV >3 ml, Group II, p < 0.0001). Group I exhibited a decreased LH response to GnRH on day 2 compared to day 1 (p < 0.01), which did not recover until day 5 (1-4 vs. 5-7 days, p < 0.0001). Group II displayed robust and equivalent LH responses to GnRH throughout the 7-day study. Genetic studies identified 8 mutations in 4 different loci (DAX1, KAL1, GNRHR, and FGFR1) in this cohort.

CONCLUSIONS

GnRH-deficient men undergoing GnRH-induced sexual maturation display an inverse relationship between FSH responsiveness to GnRH and baseline testicular size and I(B) levels. This observation implies that increasing seminiferous tubule maturity represents the major constraint on FSH responsiveness to GnRH in early puberty. In contrast, LH responsiveness to GnRH correlates directly with duration of GnRH exposure. Attenuated pituitary gonadotropin responses were noted in subjects harboring DAX1 mutations, consistent with known pituitary defects.

Characterization of mouse lysophosphatidic acid acyltransferase 3: an enzyme with dual functions in the testis

Glycerophospholipids are structural and functional components of cellular membranes as well as precursors of various lipid mediators. Using acyl-CoAs as donors, glycerophospholipids are formed by the de novo pathway (Kennedy pathway) and modified in the remodeling pathway (Lands' cycle). Various acyltransferases, including two lysophosphatidic acid acyltransferases (LPAATs), have been discovered from a 1-acylglycerol-3-phosphate O-acyltransferase (AGPAT) family. Proteins of this family contain putative acyltransferase motifs, but their biochemical properties and physiological roles are not completely understood. Here, we demonstrated that mouse LPAAT3, previously known as mouse AGPAT3, possesses strong LPAAT activity and modest lysophosphatidylinositol acyltransferase activity with a clear preference for arachidonoyl-CoA as a donor. This enzyme is highly expressed in the testis, where CDP-diacylglycerol synthase 1 preferring 1-stearoyl-2-arachidonoyl-phosphatidic acid as a substrate is also highly expressed. Since 1-stearoyl-2-arachidonoyl species are the main components of phosphatidylinositol, mouse LPAAT3 may function in both the de novo and remodeling pathways and contribute to effective biogenesis of 1-stearoyl-2-arachidonoyl-phosphatidylinositol in the testis. Additionally, the expression of this enzyme in the testis increases significantly in an age-dependent manner, and beta-estradiol may be an important regulator of this enzyme's induction. Our findings identify this acyltransferase as an alternative important enzyme to produce phosphatidylinositol in the testis.

Twenty-four hours secretion pattern of serum estradiol in healthy prepubertal and pubertal boys as determined by a validated ultra-sensitive extraction RIA

BACKGROUND

The role of estrogens in male physiology has become evident. However, clinically useful normative data for estradiol secretion in boys has not previously been established due to the insensitivity of current methods used in clinical routine. By use of a validated ultra-sensitive extraction RIA, our aim was to establish normative data from a group consisting of healthy boys in prepuberty and during pubertal development.

METHODS

Sixty-two 24-hours serum profiles (6 samples/24 hours) were obtained from 44 healthy boys (ages; 7.2-18.6 years) during their pubertal development, classified into five stages: prepuberty (testis, 1-2 mL), early (testis, 3-6 mL), mid (testis, 8-12 mL), late-1 (testis,15-25 mL, not reached final height) and late-2 (testis,15-25 mL, reached final height). Serum estradiol was determined by an ultra- sensitive extraction radioimmunoassay with detection limit 4 pmol/L and functional sensitivity 6 pmol/L.

RESULTS

Mean estradiol concentrations during 24-hours secretion increased from prepuberty (median: <4 (5-95 percentiles: <4 - 7) pmol/L) to early puberty (6 (<4 - 12 pmol/L) but then remained relatively constant until a marked increase between mid-puberty (8 (4 - 17) pmol/L) and late-1 (21 (12 - 37) pmol/L) puberty, followed by a slower increase until late-2 puberty (32 (20 - 47) pmol/L). The diurnal rhythm of serum estradiol was non-measurable in pre- and early puberty, but discerned in mid-puberty, and become evident in late pubertal stages with peak values at 0600 to 1000 h.

CONCLUSION

With the use of an ultra-sensitive extraction RIA, we have provided clinically useful normative data for estradiol secretion in boys.