Fig. 1.

Expression of the genes encoding brain-derived neurotrophic factor (BDNF) and neurotrophin-4 (NT4) in the developing human and mouse ovary. A: Expression of BDNF and NTF4 in the human fetal ovary. Expression of BDNF increased with gestation, and was significantly higher around the time of primordial follicle formation than at early gestations (a vs. b; P < 0.03). In contrast to the mouse, BDNF expression was comparable to that of NTF4. Expression of NTF4 did not change significantly over gestation. B: Expression of Bdnf and Ntf5 in the mouse feto-neonatal ovary from the onset of meiosis (embryonic day [E] 14.5) to primordial follicle formation (postnatal day [P] 2). Ntf5 transcript levels rose slightly with increasing gestation, peaking around the onset of primordial follicle formation, but this was not significant. Bdnf levels were consistently very low at all gestations examined and showed no change over the period examined.