Increase of leptin levels following exogenous administration of estrogen in women with normal menstruation.

Abstract

To investigate the acute effect of exogenous estrogen on the changes of leptin production, the time sequence of changes in plasma leptin concentration were determined following i.v. administration of premarin, a conjugated estrogen, during the follicular phase (days 5-9) in women (n = 12) with normal menstruation. The mean circulating estradiol level abruptly (P < 0.0001) increased from 4 h to a level of 72-fold from baseline and was still significantly (P < 0.05) elevated at 72 h after injection of conjugated estrogen. The mean leptin level showed a significant (P < 0.05) gradual increase from 24 h (10.8 +/- 1.0 ng/mL) continuing on up to a peak at 32 h (11.6 +/- 0.9 ng/mL); significantly (P < 0.05) sustained to 48 h (10.7 +/- 0.7 ng/mL) and then slowly decreased at 56 h after injection of premarin, as compared with the preinjection level (7.8 +/- 0.7 ng/mL). However, there were no changes of leptin levels in women (n = 10) who received normal saline injection. These data clearly suggest that a higher level of estrogen could stimulate the increase of plasma leptin concentration during the follicular phase of normal cyclic women. This result provides evidence that supraphysiological level of estrogen may act on the adipocyte to modulate leptin production through the endocrine mechanism.