UNASSIGNED: The peptide hormone Insulin-like Factor 3 (INSL3) is a biomarker of testicular Leydig cells in the male but is also expressed by the theca cells of the ovaries. With the advent of sensitive assays INSL3 can be quantified in female circulation, and we suggest that circulating INSL3 is a novel biomarker for pubertal development in girls. The aim of the study is to quantify INSL3 by LC-MS/MS in sera from normal girls during pubertal transition, and during gonadal suppression by GnRH agonist therapy in girls with central precocious puberty (CPP).
UNASSIGNED: The sensitivity of an established LC-MS/MS-based method for serum INSL3 was improved by switching to a state-of-the-art triple quadruple mass spectrometer (Altis Plus, Thermo).
UNASSIGNED: The limit of detection of the improved LC-MS/MS method for serum INSL3 was 0.01 ug/L (1.5 pM) and the inter-assay CV was < 12%. Serum INSL3 increased during the pubertal transition in healthy girls and changes correlated with the concomitant rise in other measured hormones. In some girls, but not all, INSL3, FSH, inhibin B and estradiol serum concentrations increased prior to first clinical signs of puberty. Serum INSL3 concentrations were increased at baseline in girls with CPP compared to prepubertal controls and decreased during treatment with GnRH agonist followed by a steep rise and normalization after cessation of treatment.
UNASSIGNED: The improved method allowed for quantification of INSL3 in longitudinally collected serum samples during pubertal transition in healthy girls as well as in girls with CPP before, during and after treatment with GnRH agonist. Future studies are needed to clarify if INSL3 in combination with other biomarkers enhances the predictive value of differentiating between premature thelarche and CPP.

UNASSIGNED: It is well known that metabolic disorders, including type 1 diabetes (T1D), are often associated with reduced male fertility, mainly increasing oxidative stress and impairing the hypothalamus-pituitary-testis (HPT) axis, with consequently altered spermatogenesis and reduced sperm parameters. Herein, using a rat model of T1D obtained by treatment with streptozotocin (STZ), we analyzed several parameters of testicular activity.
UNASSIGNED: A total of 10 adult male Wistar rats were divided into two groups of five: control and T1D, obtained with a single intraperitoneal injection of STZ. After 3 months, the rats were anesthetized and sacrificed; one testis was stored at -80°C for biochemical analysis, and the other was fixed for histological and immunofluorescence analysis.
UNASSIGNED: The data confirmed that T1D induced oxidative stress and, consequently, alterations in both testicular somatic and germ cells. This aspect was highlighted by enhanced apoptosis, altered steroidogenesis and Leydig cell maturity, and impaired spermatogenesis. In addition, the blood-testis barrier integrity was compromised, as shown by the reduced levels of structural proteins (N-cadherin, ZO-1, occludin, connexin 43, and VANGL2) and the phosphorylation status of regulative kinases (Src and FAK). Mechanistically, the dysregulation of the SIRT1/NRF2/MAPKs signaling pathways was proven, particularly the reduced nuclear translocation of NRF2, affecting its ability to induce the transcription of genes encoding for antioxidant enzymes. Finally, the stimulation of testicular inflammation and pyroptosis was also confirmed, as highlighted by the increased levels of some markers, such as NF-κB and NLRP3.
UNASSIGNED: The combined data allowed us to confirm that T1D has detrimental effects on rat testicular activity. Moreover, a better comprehension of the molecular mechanisms underlying the association between metabolic disorders and male fertility could help to identify novel targets to prevent and treat fertility disorders related to T1D.

Insulin-like peptide 3 (INSL3) is a biomarker for Leydig cells in the testes of vertebrates, and it is principally involved in spermatogenesis through specific binding with the RXFP2 receptor. This study reports the insl3 gene transcript and the Insl3 prepropeptide expression in both non-reproductive and reproductive tissues of Danio rerio. An immunohistochemistry analysis shows that the hormone is present at a low level in the Leydig cells and germ cells at all stages of Danio rerio testis differentiation. Considering that the insl3 gene is transcribed in Leydig cells, our results highlight an autocrine and paracrine function of this hormone in the Danio rerio testis, adding new information on the Insl3 mode of action in reproduction. We also show that Insl3 and Rxfp2 belonging to Danio rerio and other vertebrate species share most of the amino acid residues involved in the ligand-receptor interaction and activation, suggesting a conserved mechanism of action during vertebrate evolution.

Insulin-like peptide 3 (INSL3) is a circulating biomarker for Leydig cell functional capacity in men, also indicating Leydig Cell Insufficiency (LCI) and potential primary hypogonadism. Using results from large cohort studies we explore sources of biological and technical variance, and establish a reference range for adult men. It is constitutively secreted with little within-individual variation and reflects testicular capacity to produce testosterone. The main INSL3 assays available indicate good concordance with low technical variance; there is no effect of ethnicity. INSL3 declines with age from 35 years at about 15% per decade. Like low calculated free testosterone, and to a lesser extent low total testosterone, reduced INSL3 is significantly associated with increasing age-related morbidity, including lower overall sexual function, reflecting LCI. Consequently, low INSL3 (≤0.4 ng/ml; ca. <2 SD from the population mean) might serve as an additional biochemical marker in the assessment of functional hypogonadism (late-onset hypogonadism, LOH) where testosterone is in the borderline low range. Excluding individuals with low LCI (INSL3 ≤ 0.4 ng/ml) leads to an age-independent (> 35 years) reference range (serum) for INSL3 in the eugonadal population of 0.4 - 2.3 ng/ml, with low INSL3 prospectively identifying individuals at risk of increased future morbidity.

Insulin-like peptide 3 (INSL3) is a constitutive product of mature, adult-type Leydig cells of the testes and consequently in most mammals is an ideal biomarker with which to monitor pubertal development. A new heterologous time-resolved fluorescence immunoassay was developed and validated to measure circulating INSL3 in the blood of adult male dogs. Compared to other species, INSL3 concentration is low with marked variation between individuals, which appears to be independent of breed, age, or weight. A model system was then used in which a cohort of beagle dogs was subject to a GnRH-agonist implant to suppress the HPG axis and spermatogenesis, followed by implant removal and recovery. Unlike testosterone, INSL3 levels were not fully suppressed in all animals by the GnRH agonist, nor was the recovery of Leydig cell function following implant removal uniform or complete, even after several weeks. In dogs, and dissimilar from other species (including humans), Leydig-cell INSL3 appears to be quite variable between individual dogs and only weakly connected to the physiology of the HPG axis after its suppression by a GnRH-agonist implant and recovery. Consequently, INSL3 may be less useful in this species for the assessment of testis function.

Constitutively activated tyrosine kinase JAK3 is implicated in the pathogenesis of cutaneous T-cell lymphomas (CTCL). The mechanisms of constitutive JAK3 activation are unknown although a JAK3 mutation was reported in a small portion of CTCL patients. In this study, we assessed the oncogenic roles of a newly identified JAK3-INSL3 fusion transcript in CTCL. Total RNA from malignant T-cells in 33 patients with Sézary syndrome (SS), a leukemic form of CTCL, was examined for the new JAK3-INSL3 fusion transcript by RT-PCR followed by Sanger sequencing. The expression levels were assessed by qPCR and correlated with patient survivals. Knockdown and/or knockout assays were conducted in two CTCL cell lines (MJ cells and HH cells) by RNA interference and/or CRISPR/Cas9 gene editing. SS patients expressed heterogeneous levels of a new JAK3-INSL3 fusion transcript. Patients with high-level expression of JAK3-INSL3 showed poorer 5-year survival (n = 19, 42.1%) than patients with low-level expression (n = 14, 78.6%). CTCL cells transduced with specific shRNAs or sgRNAs had decreased new JAK3-INSL3 fusion transcript expression, reduced cell proliferation, and decreased colony formation. In NSG xenograft mice, smaller tumor sizes were observed in MJ cells transduced with specific shRNAs than cells transduced with controls. Our results suggest that the newly identified JAK3-INSL3 fusion transcript confers an oncogenic event in CTCL.

OBJECTIVE: Does Cushing\'s syndrome (CS) differently affect the gonadotrope axis and testicular functions (GA/TF) according to the hypercortisolism intensity and underlying etiology?
CONCLUSIONS: Endogenous cortisol excess caused by CS leads to varying degrees of hypogonadotropic hypogonadism (HH) with more severe GA/TF impairment and altered spermatogenesis in men with intense hypercortisolism associated with paraneoplastic/ectopic adrenocorticotrophic hormone (ACTH) secretion (EAS).
BACKGROUND: CS is very rarely studied in men due to its lower prevalence in men than in women. In a few old reports focusing exclusively on a limited number of men with Cushing\'s disease (CD), the occurrence of hypogonadism was reported. However, a detailed assessment of the impact of CS on the GA/TF in a significant series of patients has not been performed. Yet, hypogonadism could worsen CS-associated comorbidities such as osteoporosis and myopathy. To date, the full spectrum of GA/TF impairment in men with CS of different etiologies and intensity remains unknown.
METHODS: In this monocentric study, 89 men with CS diagnosed at a tertiary endocrine university center (Bicêtre, Paris Saclay) between January 1990 and July 2021 were evaluated and compared to 40 normal men of similar age.
METHODS: The CS patient cohort of 89 men included 51 with CD, 29 with EAS and 9 with CS of adrenal origin i.e. (ACTH-independent CS (AI-CS)). They all had frank hypercortisolism, with increased 24 h-urinary-free cortisol (24 h-UFC) in two separate samples. A case-control study was performed focusing on pituitary gonadotrope function and testicular sex steroids and peptides. An additional set of six CS men had an evaluation including semen analysis. In a subgroup of 20 men with available data after CS remission, a longitudinal analysis was conducted to assess the reversibility of GA/TF defects.
RESULTS: Compared to controls, men with CS had significantly lower total testosterone (TT), bioavailable TT, and free TT (P < 0.0001). Hypogonadism, defined as serum TT levels <3.0 ng/ml, was present in 83% of men with EAS, in 61% of men with CD, and in 33% of men with AI-CS. Low-normal LH concentrations in the included men with hypercortisolism indicated HH. Serum sex hormone-binding globulin levels were moderately decreased in men with CD (P = 0.01 vs controls). Among the CS men, those with EAS had significantly lower TT, LH, and FSH levels than those with CD or AI-CS. When compared to controls, patients with EAS were the only group exhibiting a significant decrease in both serum FSH (P = 0.002) and the testicular peptides inhibin B (P < 0.0001) and anti-Müllerian hormone (P = 0.003). Serum INSL3 levels were significantly lower in men with CD than in the controls (P = 0.03). Of note, 24 h-UFC and ACTH were inversely and significantly associated with the majority of reproductive hormones including LH, FSH, TT, and inhibin B. Following successful curative therapy, reproductive assessment at a mean of 6.0 ± 4.3 years showed a significant increase in serum TT (P < 0.0001) and plasma LH (P = 0.02) levels, indicating a reversal of HH in 75% of the affected males. Among the six patients with available semen analysis, the two EAS cases exhibited a decrease in Sertoli cell peptides associated with a severe oligozoospermia, which completely normalized following removal of the source of hypercortisolism.
CONCLUSIONS: The potential bias due to the retrospective design is counteracted by the analysis of the largest male CS cohort to date as well as the use of stringent inclusion and exclusion criteria. Due to the low number of patients with semen analysis in this study, further research is needed to unravel the full spectrum of spermatogenesis defects in men with CS.
CONCLUSIONS: This work reveals the variable spectrum of reproductive impact in men with CS. We demonstrate that GA/TF impairment depends on the intensity of hypercortisolism which in turn is related to the underlying etiology. The causal link between hypercortisolism and GA/TF impairment was attested by its reversibility in most patients after CS remission. The wider implications of our findings lie in the potential generalization to a much commoner entity, iatrogenic CS due to chronic exposure to exogenous glucocorticoids.
BACKGROUND: Several research grants were attributed to J.Y.: (i) a grant from Programme Hospitalier de Recherche Clinique (PHRC # P081212 HYPOPROTEO); (ii) a grant from the French Association of Patients with Adrenal Diseases (\'Association surrénales\'); and (iii) independent Investigator Research Grants from HRA Pharma, Novartis and Recordati Pharma. A SICPA Foundation grant (Lausanne, Switzerland) allowed protected research time for G.E.P. The above sponsors were not involved in any part of the study. The authors have no competing or other conflicts of interest to declare.
BACKGROUND: N/A.

Cryptorchidism is a common disorder in boys that has been widely studied both experimentally and clinically. The role of the gubernaculum, a mesenchymal tissue extending from the fetal testis and epididymis to the developing scrotum, is still unclear. Even the name is debated: \'gubernaculum epididymis\' or \'gubernaculum testis\'. This review does not aim to provide a global overview of competing theories on testicular descent, but focuses on the role of the gubernaculum in epididymo-testicular descent. We identified four major pitfalls of gubernaculum research: the role of the gubernaculum, of insulin-like peptide 3, anti-Müllerian hormone, and androgens. The major critical issues were that the gubernaculum plays a guiding role for the epididymis, descending prior to the testis and expanding the inguinal canal; insulin-like peptide 3 is not as important for the process of descent in humans as the rate of insulin-like peptide 3 mutations is low; anti-Müllerian hormone plays no significant role in epididymo-testicular descent; androgens and gonadotropins play a crucial role in epididymo-testicular descent. The role of the epididymis in the complex process of gubernaculum, epididymis, and testis migration is underestimated and should be included in future research.
Nunusileidusios sėklidės (kriptorchizmas) yra dažna vyriškų lytinių organų patologija. Sėklidės pavadis (lot. gubernaculum testis) – mezenchiminis audinys tarp vaisiaus sėklidės ir prielipo bei besiformuojančio kapšelio. Jo reikšmė sėklidei ir prielipui nusileisti nėra aiški. Šios apžvalgos tikslas nėra įvertinti vienų kitoms prieštaraujančių sėklidės nusileidimo teorijų, o susitelkiama ties sėklidės pavadžio (ar dar kitaip vadinamo prielipo pavadžio) svarba sėklidei nusileisti. Mes kėlėme šiuos pagrindinius klausimus apie sėklidės pavadį: sėklidės pavadžio svarba, į insuliną panašaus hormono 3, antimiulerinio hormono ir androgenų reikšmė. Sėklidės pavadis atlieka tik orientacinį vaidmenį prielipui ir leidžiasi prieš sėklidę plėsdamas kirkšnies kanalą. Į insuliną panašus hormonas nėra svarbus sėklidei nusileisti, nes žmonių populiacijos šio geno mutacijos yra retos. Antimiulerinis hormonas neatlieka reikšmingo vaidmens, kad sėklidė ir prielipas nusileistų. Androgenai ir gonadotropinai yra svarbiausi, kad įvyktų sėklidės ir prielipo nusileidimas. Prielipo reikšmė sudėtingame pavadžio, prielipo ir sėklidės migracijos procese yra nepakankamai įvertinta.

Background: Relatively large disulfide-linked polypeptides can serve as signaling molecules for a diverse array of biological processes and may be studied in animal models to investigate their function in vivo. The aim of this work was to develop an LC-MS/MS assay to measure a model peptide, INSL3, in rat plasma. Results: A dual enrichment strategy incorporating both protein precipitation and solid phase extraction was utilized to isolate INSL3 from rat plasma, followed by targeted LC-MS/MS detection. The method was able to measure full-length INSL3 (6.1 kDa) down to 0.2 ng/ml with acceptable accuracy and precision. Conclusion: The final assay was applied to support an exploratory pharmacokinetic study to evaluate steady-state concentrations of dosed INSL3 in rat plasma.

Mild Leydig cell insufficiency affects a substantial proportion of testicular cancer survivors. Previous studies have not shown a beneficial effect of testosterone replacement therapy, however, with a pronounced interindividual effect. Thus, biomarkers identifying the subgroups that might benefit are wanted. We aimed to determine if insulin-like factor 3 (INSL3), basal and human chorionic gonadotropin (hCG)-stimulated testosterone can predict the effect of testosterone replacement therapy in testicular cancer survivors with mild Leydig cell insufficiency.
We randomized adult testicular cancer survivors with mild Leydig cell insufficiency 1:1 to 12 months of transdermal testosterone replacement therapy (Tostran gel 2%) or placebo. INSL3, basal, and hCG-stimulated testosterone were measured at baseline. Outcomes (glucose, insulin, HbA1C, lipids, blood pressure, and body composition) were measured at baseline, 6 and 12 months. We applied a linear mixed-effect model comparing patients receiving testosterone with placebo in subgroups by biomarker.
We included and randomized 69 patients between October 2016 and February 2018. Patients with INSL3 and hCG-stimulated testosterone concentrations below the median had a -1.7 kg (95% CI: -3.1, -0.4) and -2.0 kg (95% CI: -3.5, -0.6) change in fat mass after 12 months of testosterone replacement therapy compared with placebo. This was not the case in patients with INSL3 and hCG-stimulated testosterone above the median. We did not find any effect of these biomarkers on glucose, insulin, HbA1c, or lipids.
Patients with INSL3 and hCG-stimulated testosterone concentrations below the median had decreased fat mass after 12 months of testosterone replacement therapy compared with placebo. It should be evaluated in larger trials if these biomarkers can be used as predictive markers identifying testicular cancer patients with mild Leydig cell insufficiency who might benefit from testosterone substitution.