Fig. 2.

Body size at puberty onset in female rats treated with nor-binaltorphimine (nor-BNI), a kappa-opioid receptor antagonist, or senktide, a neurokinin 3 receptor agonist. Vaginal openings, vaginal smears and body weights were monitored daily. Growth curves and timing of vaginal opening and of first estrus in female rats are shown in panel A. Body weights at vaginal opening and first estrus are shown in panels B and C. Numbers in each column indicate numbers of animals used. Values are means ± SEM. Values with different letters are significantly different (P < 0.05, one-way ANOVA followed by Tukey’s HSD test) from each other in each panel.