Control of Liver Gene Expression by Sex Steroids and Growth Hormone Interplay

Abstract

Sex steroids have important physiological actions, which are not limited to reproductive organs, in both females and males. They exert important physiological roles, including the regulation of somatotropic-liver axis, intermediate metabolism, or gender dimorphism. This is in part because the liver is a sex steroid-responsive organ where sex steroid- and growth hormone (GH)-dependent signaling pathways connect to regulate complex gene expression networks. Sex steroids can impact liver gene expression by a direct, through hepatic estrogen receptor (ER)α and androgen receptor (AR), or indirect mechanisms, by modulation of pituitary GH secretion and/or interaction with the GHR-STAT5b signaling pathway. Therefore, deficiency of sex steroid- and GH-dependent signaling pathways might cause a dramatic impact on mammalian liver physiology. In this chapter, we will focus our attention on main concepts and paradigms involved in the role and interplay between sex steroid- and GH-dependent signaling to regulate gene expression networks in the mammalian liver. A better understanding of how sex steroids and interactions with GH-STAT5b signaling pathway influence physiological and pathological states in the liver will contribute to improve clinical management of patients with disorders in body growth, development, and metabolism.