Figure 4.

Deposition of silver grain labeling for ERα mRNA in the neonatal rat anterior hypothalamus (females on the left side of each panel, males on the right). A–J: The representative photomicrographs depict labeling in the (A–E) AVPV and (F–J) MPOA from PND 0–19. In all cases, labeling consisted of discrete clusters of silver grains with very little background labeling. Notably (F), on PND 0, label within the MPOA was largely confined to the dorsal portion of the MPN. K,L: Quantification of silver grain deposition revealed a significant sex difference in ERα mRNA levels by PND 2 in both regions. This sex difference was eliminated by PND 7 in the AVPV, but persisted through PND 19 in the MPOA. Significant differences in expression compared with PND 0 levels are represented by (**) P ≤ 0.01, for the females. (No significant change with age was observed in the males.) Significant sex differences in expression at each age are represented by (†) P ≤ 0.05, (††) P ≤ 0.01, and (†††) P ≤ 0.001. The graphs depict mean ± SEM, and the sample size at each age is provided at the bottom. For abbreviations, see list. Scale bar = 100 µm in F (applies to A–J). [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com.]