Figure 2. The prepubertal decrease in hypothalamic Mkrn3 expression is independent of gonadal activation.

Mkrn3 expression in the ARC (left) and AVPV (right) of intact WT (white bars) and hpg (blue bars) mice across postnatal development as determined by RT-qPCR. The bar graphs show the relative change in mRNA levels in female (A) and male (B) mice, compared with levels at P10, normalized to levels of endogenous ribosomal protein L19 (RpL19) mRNA. Mean (±SEM) values are shown at each age (n = 3–4 mice per group, with each measurement performed in triplicate). Statistical analysis of effects of age and genotype were compared by 2-way ANOVA with a post hoc Tukey’s multiple-comparisons test. Mkrn3 mRNA levels decreased from P10 to P45 in the ARC and AVPV of WT mice, similarly to hpg mice. There was no difference in Mkrn3 expression between WT and hpg female or male mice across pubertal maturation in either the ARC or AVPV. Groups with different symbols (†, ‡, §) are significantly different (P = 0.0002). (C–F) Expression of Mkrn3 (C and E) and Kiss1 (D and F), quantified by RT-qPCR, in the MBH (C and D) and POA (E and F) of WT female mice treated with 2 μg of estradiol benzoate (EB)or vehicle at age P11. All mice were sacrificed 24 hours after treatment. The bar graphs show relative mRNA levels in female EB-treated (green bars) mice compared with vehicle-treated (white bars) mice, normalized to levels of endogenous RpL19 mRNA. Mean (±SEM) values are shown for 4–6 mice in each group, with each measurement performed in triplicate. Statistical analysis of effects of EB treatment was by unpaired 2-tailed t test. Asterisks indicate P < 0.0001 for D and P = 0.014 for F.