Figure 2.

Activity and expression of 17α-hydroxylase/17,20-lyase (P450c17) of rhesus adrenal microsomes from birth to 3 months of age. A, Adrenal microsomal (20 μg) 17,20-lyase activity (nmol/mg · h) measured by release of ³H-acetate from [21-³H]17α-OH-pregnenolone as described in Materials and Methods. Rhesus adrenal 17,20-lyase activity increased linearly during the first 3 months of life (R² = 0.60; P < 0.01). B, Densitometric analysis of Western immunoblots for P450c17 (pmol/μg) expression in adrenal microsomes from perinatal and neonatal rhesus macaques. Concentrations were based on comparison with a recombinant human P450c17 standard (1 pmol included in each gel). Levels of P450c17 did not change with age (P > 0.05). C, Representative Western immunoblot of P450c17 expression in perinatal and neonatal rhesus adrenal microsomes (20 μg/lane) used for densitometry to detect age-related changes.