Adrenocorticotropin Preferentially Up-Regulates Angiopoietin 2 in the Human Fetal Adrenal Gland: Implications for Coordinated Adrenal Organ Growth and Angiogenesis

Context: ACTH is the key tropic hormone for the human fetal adrenal (HFA). Because vascular development must be coordinated with organ growth, ACTH may regulate local angiogenic factors, thereby influencing HFA angiogenesis. We previously demonstrated that ACTH up-regulates vascular endothelial growth factor in HFA cortical cells. A newer angiogenic factor family, the angiopoietins (Angs), also plays critical roles. Ang1 stabilizes, whereas Ang2 destabilizes vessels, increasing responsiveness to angiogenic stimuli. Objective: The objective of this study was to investigate expression and ACTH regulation of Angs and their receptor Tie2 in the HFA. Design, Setting, and Patients: Studies were conducted involving RNA, frozen sections, and primary cell cultures from HFAs (14–24 wk) and human adult adrenal RNA. Main Outcome Measures: Angs and Tie2 mRNA levels were determined by real-time quantitative RT-PCR, Ang2 and Tie2 were localized by immunostaining, and ACTH regulation of Angs was investigated by real-time...