Figure 1.

Chronically elevated LH accelerates vaginal opening and increases in serum levels of LH are dependent on genetic background. (A) Age of vaginal opening for transgenic females (open bars) and nontransgenic controls (closed bars) was determined for two F₁ hybrid strains and the CF-1 strain. (B) Serum levels of LH were measured in 5-month-old female transgenic (open bars) and nontransgenic (closed bars) mice representing the CF-1 parental strain and the three F₁ hybrid strains. Strain designations are B6CF (C57BL/6 ♀ × CF-1,Tg ♂); CDCF (CD-1 ♀ × CF-1,Tg ♂); and SJLCF (SJL ♀ × CF-1,Tg ♂). The numbers of samples used for data sets are: CF-1 transgenics = 8, nontransgenics = 3; (C57BL/6 ♀ × CF-1,Tg ♂, transgenics = 6, nontransgenics = 7; (CD-1 ♀ × CF-1,Tg ♂, transgenics = 13, nontransgenics = 5; and (SJL ♀ × CF-1,Tg ♂), transgenics = 4, nontransgenics = 3. Values are means ± SEM.