Adrenocortical and Adipose Responses to High-Altitude-Induced, Long-Term Hypoxia in the Ovine Fetus

Figure 2

Effects of development under conditions of long-term hypoxia (LTH) on adrenocortical function in the late gestation ovine fetus. LTH increases perirenal adipose expression and release of leptin as well as adrenocortical leptin receptor (OB-Rb) expression. LTH also increases zona fasciculate-specific expression and activity of eNOS. Combined, leptin and nitric oxide (NO) serve to limit the ability of the elevated fetal plasma ACTH to stimulate cortisol production thus allowing for the maintenance of the normal ontogenic maturation of cortisol production preserving the prepartum exponential rise of this key steroid. In response to an acute secondary stress, these mechanisms allow release of cortisol synthesis thus resulting in an enhanced acute phase production of cortisol. (ZG-zona glomerulosa, ZF-zona fasciculata, M-medulla).