The central administration of IGF-1 advanced the timing of puberty. Open and solid bars represent the mean (±SEM) age in days at vaginal opening for saline and IGF-1-treated animals, respectively. Note that IGF-1 advanced vaginal opening by 4.9 days. N = 6–7/bar. *** p<0.001. (With permission, © 1996 by The Endocrine Society, [13] Hiney JK, Srivastava V, Nyberg CL, Ojeda SR, Dees WL; Endocrinology published by Oxford University Press.)