The Insulin/IGF System in Mammalian Sexual Development and Reproduction.

Neirijnck Neirijnck,Papaioannou Papaioannou,Nef Nef

doi:10.3390/ijms20184440

Neirijnck Neirijnck, Papaioannou Papaioannou + Show 1 more

Open Access

https://doi.org/10.3390/ijms20184440

Copy DOI

Abstract

Persistent research over the past few decades has clearly established that the insulin-like family of growth factors, which is composed of insulin and insulin-like growth factors 1 (IGF1) and 2 (IGF2), plays essential roles in sexual development and reproduction of both males and females. Within the male and female reproductive organs, ligands of the family act in an autocrine/paracrine manner, in order to guide different aspects of gonadogenesis, sex determination, sex-specific development or reproductive performance. Although our knowledge has greatly improved over the last years, there are still several facets that remain to be deciphered. In this review, we first briefly outline the principles of sexual development and insulin/IGF signaling, and then present our current knowledge, both in rodents and humans, about the involvement of insulin/IGFs in sexual development and reproductive functions. We conclude by highlighting some interesting remarks and delineating certain unanswered questions that need to be addressed in future studies.

Highlights

From an evolutionary point of view, metabolism, growth and reproduction are tightly connected
We briefly describe the components of the insulin/IGF system; we provide a short overview of gonadogenesis, sex determination, and sex-specific development in males and females; we present gene expression and biological data that reveal the roles played by insulin/IGF signaling during sexual development and in mediating reproductive functions
It is clear that IGFs are absolutely essential for testis differentiation and function: both receptors are necessary for testis specification [54]; for establishing SC number, testis size, and sperm output [43]; and for LC development and steroidogenic function [55]

Summary

Introduction

From an evolutionary point of view, metabolism, growth and reproduction are tightly connected. This study showed that insulin/IGF signaling is absolutely essential for sex determination and testis differentiation in mice, since triple knockout embryos display a complete male-to-female sex reversal, characterized by reduced expression of Sry and Sox9 [53].

Results

Conclusion