Synergistic Actions of Thyroid-Adipokines Axis during Development

Abstract

Thyroid hormones (THs) are involved in the programming of early prenatal period [1-37]. Moreover, adipokines [leptin (LEP), resistin (RETN), adiponectin (ADP), inflammatory cytokines [interleukin-6 (IL-6), monocyte chemoattractant protein-1 (MCP-1) and tumor necrosis factor-α (TNF-α)], and chemokines [interleukin-8 (IL-8)] play an important role during the fetal development and early life [12,32,33]. THs also control the actions of LEP [8,9], interferon-γ [38], ADP [8,9,39], TNF-α [8,26], and growth factors [8,28,32,33,35,40,41] by non-genomic mechanisms. Alternatively, LEP, ADP, and TNF-ɑ modulate the functions of thyroid axis and insulin sensitivity [8]. Also, adipokines can regulate the hypothalamic-pituitary-thyroid axis (HPTA), thermogenesis, body weight, basal metabolic rate and appetite [42]. The nuclear receptors such as thyroid receptors (TRs), peroxisome proliferator-activated receptor-α (PPARα), and liver X receptor (LXR) are vital for the triiodothyronine (T3) regulation of cholesterol metabolism and transcription of lipogenic and lipolytic genes [42]. In white adipose tissue (WAT), the expression and secretion of ADP was decreased throughout the pregnancy [13,43]. Moreover, the expression of LEP and RETN was observed in the developing placenta [44] with reducing the insulin level [45]. Also, the coordination in the secretion these cytokines is involved in the availability of energy during the gestation [46].