Hormonal profile of transgenic skinny mice overexpressing leptin (filled columns) and their nontransgenic littermates (open columns). (a) Hypothalamic GnRH contents. Hypothalami were collected from the same animals in Figure 1b. (b) Serum LH concentrations 15 minutes after intraperitoneal administrations of GnRH. Procedures were performed on day 21 (21 d) (filled columns, n = 10; open columns, n = 8), on the diestrus day at 13 weeks (13 W) (filled columns, n = 6; open columns, n = 4), and on the diestrus day at 25 weeks (25 W) (filled and open columns, n = 10) of age. (c) Serum LH concentrations at 2000 hours on the proestrus day between 13 and 18 weeks of age (filled columns, n = 6; open columns, n = 4). AP < 0.05 compared with nontransgenic littermates by ANOVA with Fisher’s least significance difference test. BP < 0.005 by Student’s t test.