Isolated follicle-stimulating hormone (FSH) deficiency in two infertile men without FSH β gene mutation: Case report and literature review

Hormone Regulation in Testicular Development and Function

The testes serve as the primary source of androgens and the site of spermatogenesis, with their development and function governed by hormonal actions via endocrine and paracrine pathways. Male fertility hinges on the availability of testosterone, a cornerstone of spermatogenesis, while follicle-stimulating hormone (FSH) signaling is indispensable for the proliferation, differentiation, and proper functioning of Sertoli and germ cells. This review covers the research on how androgens, FSH, and other hormones support processes crucial for male fertility in the testis and reproductive tract. These hormones are regulated by the hypothalamic-pituitary-gonad (HPG) axis, which is either quiescent or activated at different stages of the life course, and the regulation of the axis is crucial for the development and normal function of the male reproductive system. Hormonal imbalances, whether due to genetic predispositions or environmental influences, leading to hypogonadism or hypergonadism, can precipitate reproductive disorders. Investigating the regulatory network and molecular mechanisms involved in testicular development and spermatogenesis is instrumental in developing new therapeutic methods, drugs, and male hormonal contraceptives.

A Case of Suspected Isolated Follicle-Stimulating Hormone (FSH) Deficiency Where Spermatogenesis Was Acquired by Human Menopausal Gonadotropin (hMG)

Isolated follicle-stimulating hormone (FSH) deficiency is a rare cause of infertility in both sexes, and only a few cases have been reported in Japan. This is a case report of a young male patient with isolated FSH deficiency and azoospermia who was successfully treated with human menopausal gonadotropin (hMG). A 28-year-old male patient was referred for azoospermia. The delivery at his birth was uneventful and a family history of infertility or hypogonadism was not observed. The testes volume was 22/24 mL (right/left). No varicocele was observed in the ultrasound, and no sign or symptom of hypogonadism was found. In the semen analysis, however, the sperm concentration was as low as 2.5×10⁶/mL and the motility was less than 1%. The endocrine panel revealed luteinizing hormone (LH) (2.1 mUI/mL, normal values 0.8-5.7 mUI/mL) and testosterone (6.57 ng/ml, normal values 1.42-9.23 ng/mL) were normal, while the FSH level was very low (0.6 mUI/mL, normal values 2.0-8.3 mIU/mL). The odor and the karyotype 46, XY, were normal. The brain MRI scans showed no abnormal findings. Genitalia and potency were normal. The diagnosis was made of isolated FSH with severe oligoastenozoospermia clinically.  FSH replacement therapy was employed. The patient self-injected 150 units of hMG three times a week. After 3 months of the treatment, the sperm concentration and motility went up to 264×10⁶/mL and 12%, respectively. At 5 months, the patient's spouse conceived naturally, and at 7 months the treatment was terminated. During the treatment, FSH rose to the normal range, while other test items showed no change. The patient's health condition was uneventful. The spouse delivered a healthy boy. In conclusion, for isolated FSH with severe oligoastenozoospermia, hMG can be as effective as recombinant human FSH (rh-FSH), although the dosage remains a matter of discussion.

Luteinizing hormone β-subunit deficiency: Report of a novel LHB likely pathogenic variant and a systematic review of the published literature

CONTEXT

Selective deficiency of β-subunit of luteinizing hormone (LHB) is a rare disease with scarce data on its characteristics.

OBJECTIVES

To describe a male with LHB deficiency and systematically review the literature.

DESIGN AND PATIENTS

Description of a male patient with LHB deficiency and a systematic review of LHB deficiency patients published to date (10 males and 3 females) as per PRISMA guidelines.

RESULTS

A 36-year-old Asian Indian male presented with infertility. On evaluation, he had sexual maturity of Tanner's stage 3, low testosterone (0.23 ng/ml), low LH (0.44 mIU/ml), high follicle-stimulating hormone (FSH, 22.4 mIU/ml), and a novel homozygous missense likely pathogenic variant (p.Cys46Arg) in LHB. In the molecular dynamics simulation study, this variant interferes with heterodimerization of alpha-beta subunits. Eleven males with pathogenic variants in LHB reported to date, presented at a median age of 29 (17-38) years, most commonly with delayed puberty. Clinical and biochemical profiles were similar to those of our patient. In the majority, testosterone monotherapy modestly increased testicular volume whereas human chorionic gonadotropin (hCG) monotherapy also improved spermatogenesis. In females, oligomenorrhoea after spontaneous menarche was the most common manifestation. Ten pathogenic/likely pathogenic variants (three in-frame deletions, three missense, two splice-site, one nonsense, and one frameshift variants) have been reported in nine index patients.

CONCLUSION

We report a novel likely pathogenic LHB variant in an Asian Indian patient. The typical phenotype in male patients with LHB deficiency is delayed puberty with low testosterone, low LH, and normal to high FSH and hCG monotherapy being the best therapeutic option.

Follicle-stimulating hormone treatment for male factor infertility

Follicle-stimulating hormone (FSH) treatment has been proven effective in stimulating spermatogenesis and improving the reproductive ability of men with hypogonadotropic hypogonadism, while the usefulness of such a treatment in infertile patients with normal pituitary function is restricted to a subgroup of responders that, however, cannot be identified by the current diagnostic tools before treatment. In this review we summarize the role played by FSH in the modulation of spermatogenesis, the effect of FSH treatment at a standard replacement dose and at higher dose on sperm parameters, spontaneous and in vitro fertilization pregnancy rates, and the efforts made to identify possible responders to FSH treatment.

Revisiting the gonadotropic regulation of mammalian spermatogenesis: evolving lessons during the past decade

Spermatogenesis is a multi-step process of male germ cell (Gc) division and differentiation which occurs in the seminiferous tubules of the testes under the regulation of gonadotropins - Follicle Stimulating Hormone (FSH) and Luteinising hormone (LH). It is a highly coordinated event regulated by the surrounding somatic testicular cells such as the Sertoli cells (Sc), Leydig cells (Lc), and Peritubular myoid cells (PTc). FSH targets Sc and supports the expansion and differentiation of pre-meiotic Gc, whereas, LH operates via Lc to produce Testosterone (T), the testicular androgen. T acts on all somatic cells e.g.- Lc, PTc and Sc, and promotes the blood-testis barrier (BTB) formation, completion of Gc meiosis, and spermiation. Studies with hypophysectomised or chemically ablated animal models and hypogonadal (hpg) mice supplemented with gonadotropins to genetically manipulated mouse models have revealed the selective and synergistic role(s) of hormones in regulating male fertility. We here have briefly summarized the present concept of hormonal control of spermatogenesis in rodents and primates. We also have highlighted some of the key critical questions yet to be answered in the field of male reproductive health which might have potential implications for infertility and contraceptive research in the future.

Genetic variants of gonadotrophins and their receptors: Impact on the diagnosis and management of the infertile patient

This narrative review is concerned with genetic variants of the genes encoding gonadotrophin subunits and their receptors, as well as their implications into the diagnosis and treatment of infertility. We first review briefly the basics of molecular biology and biochemistry of gonadotrophin and gonadotrophin receptor structure and function, then describe the phenotypic effects of polymorphisms and mutations of these genes, followed by diagnostic aspects. We will then summarise the information that inactivating gonadotrophin receptor mutations have provided about the controversial topic of extragonadal gonadotrophin action. Finally, we will close with the current and future therapeutic approaches on patients with gonadotrophin and their receptor mutations.

Actions and Roles of FSH in Germinative Cells

Follicle stimulating hormone (FSH) is produced by the pituitary gland in a coordinated hypothalamic-pituitary-gonadal (HPG) axis event, plays important roles in reproduction and germ cell development during different phases of reproductive development (fetal, neonatal, puberty, and adult life), and is consequently essential for fertility. FSH is a heterodimeric glycoprotein hormone of two dissociable subunits, α and β. The FSH β-subunit (FSHβ) function starts upon coupling to its specific receptor: follicle-stimulating hormone receptor (FSHR). FSHRs are localized mainly on the surface of target cells on the testis and ovary (granulosa and Sertoli cells) and have recently been found in testicular stem cells and extra-gonadal tissue. Several reproduction disorders are associated with absent or low FSH secretion, with mutation of the FSH β-subunit or the FSH receptor, and/or its signaling pathways. However, the influence of FSH on germ cells is still poorly understood; some studies have suggested that this hormone also plays a determinant role in the self-renewal of germinative cells and acts to increase undifferentiated spermatogonia proliferation. In addition, in vitro, together with other factors, it assists the process of differentiation of primordial germ cells (PGCLCs) into gametes (oocyte-like and SSCLCs). In this review, we describe relevant research on the influence of FSH on spermatogenesis and folliculogenesis, mainly in the germ cell of humans and other species. The possible roles of FSH in germ cell generation in vitro are also presented.

Advances in the Regulation of Mammalian Follicle-Stimulating Hormone Secretion

Simple Summary

The reproduction of mammals is regulated by the hypothalamic-pituitary-gonadal axis. Follicle stimulating hormone, as one of the gonadotropins secreted by the pituitary gland, plays an immeasurable role. This article mainly reviews the molecular basis and classical signaling pathways that regulate the synthesis and secretion of follicle stimulating hormone, and summarizes its internal molecular mechanism, which provides a certain theoretical basis for the research of mammalian reproduction regulation and the application of follicle stimulating hormone in production practice.

Abstract

Mammalian reproduction is mainly driven and regulated by the hypothalamic-pituitary-gonadal (HPG) axis. Follicle-stimulating hormone (FSH), which is synthesized and secreted by the anterior pituitary gland, is a key regulator that ultimately affects animal fertility. As a dimeric glycoprotein hormone, the biological specificity of FSH is mainly determined by the β subunit. As research techniques are being continuously innovated, studies are exploring the underlying molecular mechanism regulating the secretion of mammalian FSH. This article will review the current knowledge on the molecular mechanisms and signaling pathways systematically regulating FSH synthesis and will present the latest hypothesis about the nuclear cross-talk among the various endocrine-induced pathways for transcriptional regulation of the FSH β subunit. This article will provide novel ideas and potential targets for the improved use of FSH in livestock breeding and therapeutic development.

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.