FSH for the Treatment of Male Infertility

Abstract

Follicle-stimulating hormone (FSH) supports spermatogenesis acting via its receptor (FSHR), which activates trophic effects in gonadal Sertoli cells. These pathways are targeted by hormonal drugs used for clinical treatment of infertile men, mainly belonging to sub-groups defined as hypogonadotropic hypogonadism or idiopathic infertility. While, in the first case, fertility may be efficiently restored by specific treatments, such as pulsatile gonadotropin releasing hormone (GnRH) or choriogonadotropin (hCG) alone or in combination with FSH, less is known about the efficacy of FSH in supporting the treatment of male idiopathic infertility. This review focuses on the role of FSH in the clinical approach to male reproduction, addressing the state-of-the-art from the little data available and discussing the pharmacological evidence. New compounds, such as allosteric ligands, dually active, chimeric gonadotropins and immunoglobulins, may represent interesting avenues for future personalized, pharmacological approaches to male infertility.

Keywords: FSH; biosimilars; gonadotropin; male infertility; testis.

Figure 1

Main follicle-stimulating hormone (FSH)-mediated signaling network in Sertoli cells. Intracellular FSH receptor (FSHR) interactors are indicated in blue and associated with the downstream signaling modules. Most of the signaling cascades culminate with mitotic and trophic effects in Sertoli cells, while other signals are addressed to anti-apoptotic effects and β-arrestin-mediated FSHR internalization.

Figure 2

Schematic representation of FSH, FSH-CTP, and of the FSHβ-CTP-CGβ-α and FSHβ-CTP-LHβ-CTP-α analogues; (A) FSH molecule; (B) FSH-CTP with four additional O-linked glycosylations; (C) dually active FSHβ-CTP-CGβ-α analogue. (D) dually active FSHβ-CTP-LHβ-CTP-α analogue.