Linear regression of the relationship between LH parameters and estradiol by predetermined time points. (a) Preinfusion (pre), (b) start, and (c) end time for mean LH, mean LH pulse amplitude, and number of pulses in 6 hours. Included studies: off-estradiol (−E₂) subjects no. 200, 201, 215, and 230, and on-estradiol (+E₂) subjects no. 200, 215, 230, and 232. The three remaining studies in which a GnRH bolus was given during the “start” time period were excluded.