17β-estradiol and progesterone independently augment cutaneous thermal hyperemia but not reactive hyperemia.

Objective: We examined the impact of estradiol and progesterone on skin LH and RH in 25 healthy women. Methods: Subjects were studied three times over 10-12 days. Endogenous sex hormones were suppressed with a GnRHa. Subjects were studied on day 4 of suppression (study day 1), three to four days later following treatment with either 17 beta-estradiol or progesterone (study day 2), and another three to four days later, following treatment with both estradiol and progesterone (study day 3). Subjects underwent identical LH and RH protocols on all study days. LH is characterized by an initial peak in blood flow, followed by a prolonged plateau. A brief nadir is seen between the phases. Results: Blood flow values are expressed as percent maximum CVC. Estradiol alone increased initial peak CVC from 71 +/- 2% to 79 +/- 2% (p = 0.001). Progesterone alone increased initial peak CVC from 72 +/- 2% to 78 +/- 2% (p = 0.046). Neither estradiol nor progesterone increased plateau CVC. No significant changes were seen between study days 2 and 3 for either group. No differences were observed in RH. Conclusions: Both estradiol and progesterone increased initial peak CVC during LH, without altering plateau CVC. There was no additive effect of estradiol and progesterone.