Dataset for: Progesterone administration does not acutely alter LH pulse secretion in the mid-follicular phase in women

It remains unclear how rapidly progesterone suppresses luteinizing hormone (LH) pulse frequency in women. Previous studies suggested that progesterone markedly increases LH pulse amplitude but does not slow LH pulse frequency within 10 hours in estradiol-pretreated women studied during the late follicular phase. However, this experimental paradigm may be a model of preovulatory physiology, and progesterone may have different effects at other times of the cycle. We studied regularly cycling, non-obese women without hyperandrogenism to assess the acute effect of progesterone during the mid-follicular phase and in the absence of estradiol pretreatment. The study involved two admissions in separate cycles (cycle days 5-9). For each admission, either oral micronized progesterone (100 mg) or placebo was administered at 0900 h in a randomized, double-blind fashion. Frequent blood sampling was performed between 0900 and 1900 h to define 10-hour LH pulsatility. Treatment crossover (placebo exchanged for progesterone and vice versa) occurred in a subsequent cycle. After an interim futility analysis, the study was halted after 7 women completed study. Mean progesterone concentrations after placebo and progesterone administration were 0.5 ± 0.1 (mean ± SD) and 6.7 ± 1.6 ng/ml, respectively. Compared to placebo, progesterone was not associated with a significant difference in 10-hour LH pulse frequency (0.79 ± 0.35 vs. 0.77 ± 0.28 pulses/hour, p = 1.0) or amplitude (3.6 ± 2.8 vs. 4.3 ± 2.8 IU/L, p = 0.30). This study suggests that LH pulse frequency is not rapidly influenced by progesterone administration during the mid-follicular phase.