Human Fetal Ovary Development Involves the Spatiotemporal Expression of P450c17 Protein

Objective: The purpose of this research was to characterize the spatiotemporal expression of P450c17 in the human fetal ovary. Design: P450c17 protein was visualized in sections of control and anencephalic ovaries using immunohistochemistry. Subjects: Subjects included control (nonanencephalic) and anencephalic human fetal ovaries during the second and third trimesters. Results: In second-trimester control ovaries, P450c17 was highly expressed in primary interstitial cells (PIC) located between the ovigerous cords near the cortical-medullary border where meiosis and primordial follicle formation were occurring. Morphometric analysis revealed a progressive decrease in the number of PIC during the second trimester, suggesting that PIC might have a finite lifetime. Between 25 and 32 wk, relatively few cells stained positive for P450c17; however, after 33 wk, P450c17 was strongly expressed in theca interstitial cells (TIC) bordering developing follicles. Surprisingly, the TIC appeared remarkably early during ...