Effect of chronic peripheral administration of kisspeptin on pubertal onset in female rats. (A) The day of vaginal opening (VO) was noted in rats treated with either saline or kisspeptin from day 25 to day 50 (26 days). Control vs. kisspeptin treated group: p = 0.01, Kaplan-Meier survival analysis followed by Gehan-Breslow test. (B) The percentage of animals that have reached puberty was compared between control and treated rats at time point when 25, 50, 75 and 100% of control rats have shown VO. At the respective time points, only 0, 0, 22 and 89% of kisspeptin treated rats have shown VO (p < 0.0001, Chi-square test). (C) Body weight on the day of VO was not different among the two groups. Data expressed as mean ± SEM.