Combined gonadotropin therapy to replace mini-puberty in male infants with congenital hypogonadotropic hypogonadism.

Infants born with severe central disorders of the hypothalamic-pituitary-gonadal axis leading to gonadotropin deficiency not only lack pubertal development in adolescence, but also lack infantile mini-puberty. This period of mini-puberty, where infants have gonadotropin and sex steroid concentrations up into the adult range, is vital for future reproductive capacity, particularly in boys. At present, there is no consensus on the diagnosis or management of infants with gonadotropin deficiency due to congenital hypogonadotropic hypogonadism or multiple pituitary hormone deficiency. Case series suggest that gonadotropin treatment in male infants with absent mini-puberty is effective in promoting both testicular descent in those with undescended testes and also facilitating increased penile size. Moreover, replacement with follicle-stimulating hormone increases the testicular Sertoli cell population, measurable as an increase in testicular volume and inhibin B, thus hypothetically increasing the capacity for spermatogenesis in adult life for these patients. However, long-term follow-up data is limited for both outcomes pertaining to fertility and nonreproductive sequelae, including neurodevelopment and psychological well-being. The use of international registries for patients with gonadotropin deficiency is a key element in the collection of high-quality, geographically widespread data to inform best-practice management from birth to adulthood.

Pulsatile gonadotropin releasing hormone therapy for spermatogenesis in congenital hypogonadotropic hypogonadism patients who had poor response to combined gonadotropin therapy.

Objective: Both pulsatile gonadotropin-releasing hormone (GnRH) and combined gonadotropin therapy are effective to induce spermatogenesis in men with congenital hypogonadotropic hypogonadism (CHH). This study aimed to evaluate the effect of pulsatile GnRH therapy on spermatogenesis in male patients with CHH who had poor response to combined gonadotropin therapy. Materials and methods: Patients who had poor response to combined gonadotropin therapy ≥ 6 months were recruited and shifted to pulsatile GnRH therapy. The rate of successful spermatogenesis, the median time to achieve spermatogenesis, serum gonadotropins, testosterone, and testicular volume were used for data analysis. Results: A total of 28 CHH patients who had poor response to combined gonadotropin (HCG/HMG) therapy for 12.5 (6.0, 17.75) months were recruited and switched to pulsatile GnRH therapy for 10.0 (7.25, 16.0) months. Sperm was detected in 17/28 patients (60.7%). The mean time for the appearance of sperm in semen was 12.0 (7.5, 17.5) months. Compared to those who could not achieve spermatogenesis during pulsatile GnRH therapy, the successful group had a higher level of LH60min (4.32 vs. 1.10 IU/L, P = 0.043) and FSH60min (4.28 vs. 1.90 IU/L, P = 0.021). Testicular size increased during pulsatile GnRH therapy, compared to previous HCG/ HMG therapy (P < 0.05). Conclusion: For CHH patients with prior poor response to one year of HCG/ HMG therapy, switching to pulsatile GnRH therapy may induce spermatogenesis.

Mini-Puberty, Physiological and Disordered: Consequences, and Potential for Therapeutic Replacement.

There are 3 physiological waves of central hypothalamic-pituitary-gonadal (HPG) axis activity over the lifetime. The first occurs during fetal life, the second-termed "mini-puberty"-in the first months after birth, and the third at puberty. After adolescence, the axis remains active all through adulthood. Congenital hypogonadotropic hypogonadism (CHH) is a rare genetic disorder characterized by a deficiency in hypothalamic gonadotropin-releasing hormone (GnRH) secretion or action. In cases of severe CHH, all 3 waves of GnRH pulsatility are absent. The absence of fetal HPG axis activation manifests in around 50% of male newborns with micropenis and/or undescended testes (cryptorchidism). In these boys, the lack of the mini-puberty phase accentuates testicular immaturity. This is characterized by a low number of Sertoli cells, which are important for future reproductive capacity. Thus, absent mini-puberty will have detrimental effects on later fertility in these males. The diagnosis of CHH is often missed in infants, and even if recognized, there is no consensus on optimal therapeutic management. Here we review physiological mini-puberty and consequences of central HPG axis disorders; provide a diagnostic approach to allow for early identification of these conditions; and review current treatment options for replacement of mini-puberty in male infants with CHH. There is evidence from small case series that replacement with gonadotropins to mimic "mini-puberty" in males could have beneficial outcomes not only regarding testis descent, but also normalization of testis and penile sizes. Moreover, such therapeutic replacement regimens in disordered mini-puberty could address both reproductive and nonreproductive implications.

Mixed hypogonadism: a neglected combined form of hypogonadism.

PURPOSE: Kallmann syndrome is a rare disease characterized by delayed puberty, infertility and anosmia. We report the clinical and genetic characteristics of three patients with Kallmann syndrome who presented with Klinefelter syndrome and defined this neglected combined form of hypogonadism as mixed hypogonadism. METHODS: Clinical data and examinations were obtained, including laboratory examination and magnetic resonance imagination (MRI) of the olfactory structures. Congenital hypogonadotropic hypogonadism (CHH) related genes were screened by next generation sequencing (NGS). RESULTS: Three patients with Kallmann syndrome were included. They had co-existence with Klinefelter syndrome and showed hypogonadotropic hypogonadism. Patient 1 was complicated with germinoma. CONCLUSION: Mixed hypogonadism was defined as hypogonadotropic hypogonadism in Klinefelter syndrome or primary testicular disease. Clinicians should be alert to mixed hypogonadism when spermatogenesis induction failed in patients with CHH or gonadotropin levels decrease in patients with Klinefelter syndrome.

Pulsatile gonadotropin releasing hormone therapy for spermatogenesis in congenital hypogonadotropic hypogonadism patients who had poor response to combined gonadotropin therapy

ABSTRACT Objective: Both pulsatile gonadotropin-releasing hormone (GnRH) and combined gonadotropin therapy are effective to induce spermatogenesis in men with congenital hypogonadotropic hypogonadism (CHH). This study aimed to evaluate the effect of pulsatile GnRH therapy on spermatogenesis in male patients with CHH who had poor response to combined gonadotropin therapy. Materials and methods: Patients who had poor response to combined gonadotropin therapy ≥ 6 months were recruited and shifted to pulsatile GnRH therapy. The rate of successful spermatogenesis, the median time to achieve spermatogenesis, serum gonadotropins, testosterone, and testicular volume were used for data analysis. Results: A total of 28 CHH patients who had poor response to combined gonadotropin (HCG/HMG) therapy for 12.5 (6.0, 17.75) months were recruited and switched to pulsatile GnRH therapy for 10.0 (7.25, 16.0) months. Sperm was detected in 17/28 patients (60.7%). The mean time for the appearance of sperm in semen was 12.0 (7.5, 17.5) months. Compared to those who could not achieve spermatogenesis during pulsatile GnRH therapy, the successful group had a higher level of LH60min (4.32 vs. 1.10 IU/L, P = 0.043) and FSH60min (4.28 vs. 1.90 IU/L, P = 0.021). Testicular size increased during pulsatile GnRH therapy, compared to previous HCG/HMG therapy (P < 0.05). Conclusion: For CHH patients with prior poor response to one year of HCG/HMG therapy, switching to pulsatile GnRH therapy may induce spermatogenesis.

Congenital hypogonadotropic hypogonadism in a patient with a de novo POGZ mutation.

OBJECTIVE: Congenital hypogonadotropic hypogonadism (CHH) is a rare, genetically heterogeneous reproductive disorder caused by gonadotropin-releasing hormone (GnRH) deficiency. Approximately half of CHH patients also have decreased or absent sense of smell, that is, Kallmann syndrome (KS). We describe a patient with White-Sutton syndrome (developmental delay and autism spectrum disorder) and KS due to a heterozygous de novo mutation in POGZ (c.2857C>T, p.(Gln953*)), a gene encoding pogo transposable element derived with zinc finger domain, which acts as a transcriptomic regulator of neuronal networks. DESIGN AND METHODS: We modeled the role of POGZ in CHH by generating 2 clonal human pluripotent stem cell lines with CRISPR/Cas9, carrying either the heterozygous patient mutation (H11 line) or a homozygous mutation (c.2803-2906del; p.E935Kfs*7 encoding a truncated POGZ protein; F6del line). RESULTS: During the differentiation to GnRH neurons, neural progenitors derived from F6del line displayed severe proliferation defect, delayed wound-healing capacity, downregulation of intermediate progenitor neuron genes TBR1 and TBR2, and immature neuron markers PAX6 and TUBB3 and gave rise to fewer neurons with shorter neurites and less neurite branch points compared to the WT and H11 lines (P < .005). Both lines, however, could be successfully differentiated to GnRH neurons. CONCLUSIONS: In conclusion, this is the first report on the overlap between White-Sutton syndrome and CHH. POGZ mutations do not hinder GnRH neuron formation but may cause CHH/KS by affecting the size and motility of the anterior neural progenitor pool and neurite outgrowth.

Digenic Congenital Hypogonadotropic Hypogonadism Due to Heterozygous GNRH1 p.R31C and AMHR2 p.G445_L453del Variants.

A 28-year-old man with congenital hypogonadotropic hypogonadism (CHH) was found to be heterozygous for the GNRH1 p.R31C mutation, reported in the literature as pathogenic and dominant. The same mutation was found in his son at birth, but the testing of the infant at 64 days confirmed the hormonal changes associated with minipuberty. This led to further genetic sequencing of the patient and his son, which found a second variant, AMHR2 p.G445_L453del, in the heterozygous form, reported as pathogenic in the patient but not in his son. This suggests a digenic cause of the patient's CHH. Together, these mutations are postulated to contribute to CHH by the lack of anti-Müllerian hormone (AMH) signalling, leading to the impaired migration of gonadotrophin releasing hormone (GnRH) neurons, the lack of the AMH effect on GnRH secretion, and altered GnRH decapeptide with reduced binding to GnRH receptors. This led us to the conclusion that the observed GNRH1 mutation in the heterozygous state is not certain to be dominant or, at least, exhibits incomplete penetrance and variable expressivity. This report also emphasises the opportunity afforded by the time window of minipuberty in assessing the inherited genetic disorders of hypothalamic function.

The initiation and maintenance of gonadotropin-releasing hormone neuron identity in congenital hypogonadotropic hypogonadism.

Neurons that secrete gonadotropin-releasing hormone (GnRH) drive vertebrate reproduction. Genetic lesions that disrupt these neurons in humans lead to congenital hypogonadotropic hypogonadism (CHH) and reproductive failure. Studies on CHH have largely focused on the disruption of prenatal GnRH neuronal migration and postnatal GnRH secretory activity. However, recent evidence suggests a need to also focus on how GnRH neurons initiate and maintain their identity during prenatal and postnatal periods. This review will provide a brief overview of what is known about these processes and several gaps in our knowledge, with an emphasis on how disruption of GnRH neuronal identity can lead to CHH phenotypes.

Successful pregnancy and delivery after ovulation induction therapy in a woman with congenital hypogonadotropic hypogonadism: a case report.

BACKGROUND: Congenital hypogonadotropic hypogonadism (CHH) is a rare disorder resulting from a deficient secretion of the episodic gonadotropin-releasing hormone, leading to delayed or absent puberty and infertility. In female patients with CHH, the most commonly used treatment is gonadotropin (Gn) therapy. Due to the rarity of the disease in females, there are limited case reports available. This article offers a management approach for this unusual disease that can be helpful for clinicians. CASE PRESENTATION: We report the case of a 29-year-old woman who successfully achieved pregnancy and delivered healthy twin girls after ovulation induction therapy. The patient was diagnosed with CHH at 18 years of age due to primary amenorrhea and the absence of secondary sexual characteristics. After experiencing infertility for three years, the patient sought medical assistance for conceiving. The patient was treated with gonadotropin therapy due to anovulation. In her first treatment cycle, the initial dose of HMG used for treatment was 75IU, which was increased to 150IU after six days. However, the cycle was canceled due to follicular dysplasia. In the second cycle, the treatment began with an initial dose of 150IU, and the follicles grew normally, but the estrogen level was low. Consequently, the treatment was interrupted. In a third ovulation stimulation cycle, HMG was adjusted to 150IU, and recombinant LH was added. After 12 days of ovulation, three mature follicles grew, the estrogen level was normal,and the treatment resulted in successful ovulation and subsequent pregnancy. At 35 weeks of gestation, the patient underwent a cesarean section and delivered two healthy female infants weighing 2,405 g and 2,755 g with an Apgar score of 10/10. CONCLUSIONS: Early diagnosis and timely and appropriate hormone replacement therapy are important for future pregnancy. Ovulation induction therapy is necessary to stimulate fertility. Gn therapy is a feasible and effective treatment for reproduction in CHH females, but the selection of Gn type and dosage must be personalized to maximize fertility outcomes. Effective treatment is available not only for inducing estrogenization and promoting fertility, but also for addressing concerns about psychological and emotional well-being.

Seminal plasma metabolomics signatures of normosmic congenital hypogonadotropic hypogonadism.

Background: Normosmic congenital hypogonadotropic hypogonadism (nCHH) is a rare disease, whose pathogenesis remains unclear. Here, we conducted untargeted metabolomics and lipidomics to identify seminal plasma signatures of nCHH, and to study the effect of LH and FSH deficiency on semen. Methods: Twenty-five diagnosed patients with nCHH (HH group) and twenty-three healthy participants (HC group) were enrolled. Laboratory parameters, seminal plasma samples and patients' medical data were collected. Untargeted metabolomics and lipidomic profiling were performed using mass spectrometry (MS). Results: The metabolomics profiling are altered among patients with nCHH and healthy controls. There are 160 kinds of differential metabolites and the main different lipid species are TAG, PC, SM and PE. Conclusions: The metabolomics profiles in patients with nCHH changed. We hope that this work provides important insights into the pathophysiology of nCHH.

SIN3A Defects Associated with Syndromic Congenital Hypogonadotropic Hypogonadism: An Overlap with Witteveen-Kolk Syndrome.

INTRODUCTION: Congenital hypogonadotropic hypogonadism (CHH) is a rare condition caused by GnRH deficiency. More than 40 genes have been associated with the pathogenesis of CHH, but most cases still remain without a molecular diagnosis. Mutations involving the same gene (e.g., FGFR1, PROK2/PROKR2, CHD7) were found to cause normosmic CHH and Kallmann syndrome (KS), with and without associated phenotypes, illustrating the coexistence of CHH with signs of other complex syndromes. The Witteveen-Kolk syndrome (WITKOS), caused by defects of the SIN3A gene, is a heterogeneous disorder characterized by distinctive facial features, microcephaly, short stature, delayed cognitive, and motor development. Although micropenis and cryptorchidism have been reported in this syndrome, WITKOS has not been formally associated with CHH so far. PATIENTS AND METHODS: A man with KS associated with mild syndromic features (S1) and a boy with global developmental delay, syndromic short stature, micropenis and cryptorchidism (S2), in whom common genetic defects associated with CHH and short stature had been previously excluded, were studied by either chromosomal microarray analysis or whole exome sequencing. RESULTS: Rare SIN3A pathogenic variants were identified in these 2 unrelated patients with CHH phenotypic features. A 550 kb deletion at 15q24.1, including the whole SIN3A gene, was identified in S1, and a SIN3A nonsense rare variant (p.Arg471*) was detected in S2. CONCLUSION: These findings lead us to propose a link between SIN3A defects and CHH, especially in syndromic cases, based on these 2 patients with overlapping phenotypes of WITKOS and CHH.

Genetic and phenotypic differences between sexes in congenital hypogonadotropic hypogonadism (CHH): Large cohort analysis from a single tertiary centre.

Background: Congenital hypogonadotropic hypogonadism (CHH) is a condition with a strong genetic background, caused by a deficient production, secretion, or action of gonadotropin-releasing hormone (GnRH). Published data on CHH cohorts indicate a male predominance, although this is not supported by our current understandings. Aims: In order to unravel the possible causes or contributors to such epidemiological sex difference, the aim of our study is to investigate differences in genetic background and clinical presentation between males and females in a large cohort of CHH patients. Materials and methods: We enrolled 338 CHH patients with absent or arrested pubertal development, referred to our Center from 01/2016. Data collection included clinical assessment at diagnosis and genetic analysis performed by next generation sequencing (NGS), employing a custom panel of 28 candidate genes. Results: Among 338 patients 94 were female (F) and 244 male (M), with a ratio of 1:2.6. We found that 36.09% (122/338) of patients harbored potentially pathogenic rare genetic variants (RVs) with no significant differences between sexes; on the other hand, a significantly higher frequency of oligogenicity was observed in females (F 9,57% 9/94 vs M 3,69% 9/244, P = 0.034). The prevalence of non-reproductive phenotypic features was significantly higher (P = 0.01) in males (53/228, 23.2%) than in females (10/93, 10.8%): in particular, kidney abnormalities affected only male patients and midline defects had a significantly higher prevalence in males (P = 0.010). Finally, BMI SDS was -0.04 ± 1.09 in females and 0.69 ± 1.51 in males, with a statistically significant difference between groups (P = <0.001). Conclusion: Our data confirm the male predominance in CHH and identify some differences with regard to the clinical presentation between males and females that could indicate a variable expression of genetic rare variants and a dimorphic modulation of phenotype according to metabolic/behavioral factors, which will need to be substantiated and investigated by further studies.

Recovery of hypothalamic-pituitary-gonadal function with low dose testosterone treatment in a male with congenital hypogonadotropic hypogonadism.

Congenital hypogonadotropic hypogonadism (CHH) is a rare disease caused by deficiency or action of gonadotropin-releasing hormone. While generally considered a long-life condition, CHH can be reversible in about 5%-20% of cases, but mechanisms of reversibility are unknown. We report the case of a male with CHH who began treatment with low dose (20 mg/day) transdermal testosterone to induce pubertal development at age 17. Following the start of treatment, he experienced testicular growth and his serum testosterone concentrations increased beyond the expectations in relation to the dose. Treatment was withdrawn, but this led to the reappearance of symptoms of hypogonadism and a drop in testosterone levels. Testosterone was again prescribed at the same dose and, for the subsequent years, he completed full puberty, including attainment of 20 cc testicular volume, mature secondary sexual characteristics, normal levels of testosterone and only partially arrested germinal function, as demonstrated by inhibin B levels and spermogram. Testosterone treatment was withdrawn three more times, but hypogonadism resumed on each occasion. This case suggests that low-dose testosterone treatment can induce reversal of CHH through the activation, albeit non-permanent, of the hypothalamic-pituitary-gonadal axis, indicating that testosterone administration might be a reliable therapeutic option for reverting GnRH deficiency.

GNRHR-related central hypogonadism with spontaneous recovery - case report.

BACKGROUND: Congenital hypogonadotropic hypogonadism (CHH) is a clinically and genetically heterogeneous disease characterized by absent or incomplete puberty and infertility. Clinical characteristics are secondary to insufficient gonadotropin secretion, caused by deficient gonadotropin-releasing hormone (GnRH) production, secretion, or action. Loss-of-function variants of the gonadotropin-releasing hormone receptor (GNRHR) are associated with CHH without anosmia. CHH was previously considered a permanent condition, but in the past two decades, cases of spontaneous recovery of CHH have been reported. The reversal of hypogonadism in CHH is currently unpredictable, and can happen unnoticed. CASE PRESENTATION: The male proband was diagnosed with CHH due to compound heterozygosity for two previously reported pathogenic missense variants in the GNRHR gene, NM_000406.2:c.416G > A (NP_000397.1:p.Arg139His) and c.785G > A (p.Arg262Gln) at 16 years of age. In addition to arrested partial puberty, he had a low testosterone level, gonadotropins in the range of early puberty, and a normal inhibin B level. A therapy with increasing doses of intramuscular testosterone undecanoate was received for 2.5 years, while there was no change in testicular volume. At the age of 19 years, testosterone supplementation was interrupted. During the next two years, he had spontaneous pubertal development to achieve a testicular volume of 20 mL, with normal adult levels of gonadotropins and testosterone. CONCLUSIONS: Genetic diagnostics can help discriminate congenital hypogonadotropic hypogonadism, deserving therapeutic intervention, from the self-limited constitutional delay of growth and puberty (CDGP). Patients with GNRHR associated hypogonadism can experience spontaneous recovery of the hypothalamic-pituitary-gonadal axis. Spontaneous testis enlargement in patients with central hypogonadism not taking gonadotropins or pulsatile GnRH therapy can indicate recovery of hypogonadism.

Treatment of congenital hypogonadotropic hypogonadism in male patients.

Congenital hypogonadotropic hypogonadism (CHH) is characterized by complete or partial failure of pubertal development because of inadequate secretion of gonadotropic hormones. CHH consists of hypogonadotropic hypogonadism with anosmia or hyposmia, Kallmann syndrome, and the normosmic variation normosmic idiopathic hypogonadotropic hypogonadism. CHH is one of the few treatable diseases of male infertility, although men with primary testicular dysfunction have irreversibly diminished spermatogenic capacity. The approach to CHH treatment is determined by goals such as developing virilization or inducing fertility. This review focuses on the current knowledge of therapeutic modalities for inducing puberty and fertility in men with CHH.

The genetic diagnosis of rare endocrine disorders of sex development and maturation: a survey among Endo-ERN centres.

Differences of sex development and maturation (SDM) represent a heterogeneous puzzle of rare conditions with a large genetic component whose management and treatment could be improved by an accurate classification of underlying molecular conditions, and next-generation sequencing (NGS) should represent the most appropriate approach. Therefore, we conducted a survey dedicated to the use and potential outcomes of NGS for SDM disorders diagnosis among the 53 health care providers (HCP) of the European Reference Network for rare endocrine conditions. The response rate was 49% with a total of 26 HCPs from 13 countries. All HCPs, except 1, performed NGS investigations for SDM disorders on 6720 patients, 3764 (56%) with differences of sex development (DSD), including 811 unexplained primary ovarian insufficiency, and 2956 (44%) with congenital hypogonadotropic hypogonadism (CHH). The approaches varied from targeted analysis of custom gene panels (range: 11-490 genes) in 81.5% of cases or whole exome sequencing with the extraction of a virtual panel in the remaining cases. These analyses were performed for diagnostic purposes in 21 HCPs, supported by the National Health Systems in 16 cases. The likelihood of finding a variant ranged between 7 and 60%, mainly depending upon the number of analysed genes or criteria used for reporting, most HCPs also reporting variants of uncertain significance. These data illustrate the status of genetic diagnosis of DSD and CHH across Europe. In most countries, these analyses are performed for diagnostic purposes, yielding highly variable results, thus suggesting the need for harmonization and general improvements of NGS approaches.

An Indonesian male with congenital hypogonadotropic hypogonadism: A case report and literature review.

Introduction: Congenital hypogonadotropic hypogonadism (CHH) is a rare disorder caused by insufficient gonadotropin-releasing hormone (GnRH) production. Case presentation: An Indonesian adolescent, 22 years old, Javanese ethnic, complained of a small penis, low sexual desire, fatigue, and anosmia since childhood. Medical history stated that the patient had low testosterone levels 7 years ago and received testosterone once. Testosterone, luteinizing hormone (LH), and follicle-stimulating hormone (FSH) were decreased. The testicular ultrasound result was bilateral microtestis, suspicious of bilateral hypoplasia of the epididymis. Brain MRI also supports the diagnosis of hypogonadotropic hypogonadism, and the patient received Sustanon of 250 mg/2 weeks. The patient showed a good prognosis after 1 month of therapy. Discussion: The success of CHH therapy must be explored to improve its management. Conclusion: CHH in an Indonesian male shows a good prognosis with testosterone injection.

Changes in levels of testosterone, insulin sensitivity and metabolic profiles during GnRH therapy: Reciprocity between insulin sensitivity and pituitary responsiveness to GnRH in teenage and young male patients with congenital hypogonadotropic hypogonadism.

OBJECTIVES: A direct evaluation of insulin sensitivity on pituitary response to gonadotropin relasing hormone (GnRH) has not been shown in congenital hypogonadotropic hypogonadism (CHH), despite a growing body of evidence in the association of testosterone concentrations with insulin sensitiviy. The objective of the study was to explore whether increased testosterone concentrations in men with CHH improve insulin sensitivity, or vice versa. DESIGN: A retrospective study at a tertiary centre. PATIENTS: Series of male CHH patients were included from Jannuary 2014 to December 2019. MEASUREMENTS: Insulin sensitivity indices calculated from oral glucose tolerance test and steroid hormone levels were examined in 52 patients with newly diagnosed CHH and 22 healthy controls. Thirty-two of the 52 CHH patients received pulsatile GnRH therapy with follow-up every 3-6 months. RESULTS: Compared to healthy controls, CHH patients had elevated 2 h post-load glucose, HbA1c, fasting insulin, HOMA of insulin resistance (HOMA-IR) and decreased Matsuda index and testosterone (p ≤ .01). The median follow-up for patients (n = 32) who received pulsatile GnRH therapy was 13.5 (11.3-24) months (432 person-months in total). GnRH therapy increased testosterone and Matsuda index (p ≤ .0001), whilst decreased platelet count (p = .04), leptin (p = .04), fasting glucose (p = .01) and HOMA-IR (p < .0001) compared with baseline. The median treatment duration first time to reach the lower limit of normal testosterone concentrations of patients with high and low baseline insulin sensitivity was 15 (95% CI: 8.1-21.9) and 30 months (21.2-38.8), respectively. Correspondingly, after GnRH therapy, luteinizing hormone responsiveness to GnRH provocative test was more vigorous in patients with high insulin sensitivity than those with low insulin sensitivity [17.0 (9.5-25.9) vs. 8.2 (3.3-13.0), p = .01]. CONCLUSION: Pulsatile GnRH therapy elevated testosterone levels in male CHH patients, ameliorated impaired insulin sensitivity and attenuated subclinical inflammatory response, increased insulin sensitivity, in turn, may benefit the efficacy of pulsatile GnRH therapy.