A role for epidermal growth factor in the morphological and functional maturation of the adrenal gland in the fetal rhesus monkey in vivo

We determined the effects of epidermal growth factor (EGF/and β-methasone on the growth and development of the adrenal gland of the fetal rhesus monkey in vivo between 121-128 days of gestation. The adrenal to body weight ratio was significantly greater (P < 0.05) in EGF treated fetuses (0.988 ± 0.046 x 10^-3 g/g) and significantly reduced (P < 0.05) in β-methasone-treated fetuses (0.401 ± 0.056 x 10^-3 g/g) compared with that in control fetuses (0.689 ± 0.050 x 10^-3 g/g). The increase in adrenal weight with EGF administration was due to hypertrophy of definitive zone cells of the adrenal cortex, whereas the reduction in adrenal weight after β-methasone treatment was due to a decrease in the size of definitive and fetal zone cells of the adrenal cortex. By Western analysis, EGF treatment induced a significant(P < 0.05) 2.8-fold increase in the amount of protein for 3/3-hydroxysteroid dehydrogenase/isomerase (3βHSD) in the fetal adrenal. EGF also stimulated the induction of immunocytochemical staining for 3βHSD in transitional zone cells of the adrenal cortex. In contrast, β-methasone resulted in 2.6-, 4.5- , and 6.6-fold significant decreases (P < 0.05) in the amount of protein for cytochrome P450 cholesterol side-chain cleavage, cytochrome P450 17α- hydroxylase/17,20-lyase, and 3βHSD in the fetal adrenal. After β-methasone treatment, 3βHSD staining was detected in some of the definitive zone cells, with no 3βHSD staining in the transitional zone. In conclusion, growth and functional differentiation of fetal primate adrenal gland can be accelerated prematurely by EGF and inhibited by glucocorticoid negative feedback.