Figure 5

Treatment with a proestrous level of E2 (high E2) induced a surge-like increase in LH in OVX Kiss1-floxed/Oprk1-Cre rats, but the LH surge was attenuated by the conditional Kiss1 deletion in cells expressing or having expressed Oprk1. (a) Mean plasma LH profiles of OVX + high E2 Kiss1-floxed/Oprk1-Cre rats and Cre(−)/Kiss1-floxed control rats. The area under the curve of the afternoon LH surge (b), the peak levels of the LH surge (c), the baseline LH levels (d), and the ratios of the peak levels of the LH surge to the baseline LH levels (e) in OVX + high E2 Kiss1-floxed/Oprk1-Cre rats and Cre(−)/Kiss1-floxed control rats. Values are the means ± SEM. Numbers in each column indicate the number of animals used. An asterisk indicates a statistically significant difference (p < 0.05) between the groups based on Student’s t-test.