EFFECTS OF 17-BETA-ESTRADIOL ON CIRCULATING ADHESION MOLECULES

The effects of 17 beta-estradiol (E(2)) On the serum levels of the cir culating endothelial-leukocyte, intercellular, and vascular adhesion m olecules [ELAM-1, ICAM-1 (CD54), and VCAM-1] were evaluated in healthy male volunteers after single im injection of 10 mg E(2) valerate. In addition, a time course of the effects of E(2) On circulating adhesion molecules (AMs), cortisol serum levels, differential blood counts, an d surface expression of the lymphocyte function-associated antigen-1 ( CD11a/CD18), CD3, CD4, CD19, and CD25 on leukocytes was studied in ano ther group of volunteers. A 5% decrease in circulating ICAM-1 (P = 0.0 45 vs. placebo) was found when a single time point (96 h after E(2) in jection) was studied. However, this decrease was smaller than the intr asubject (day to day) variability observed, and there was no consisten t and time-dependent effect of E(2) On circulating AMs. Circulating ne utrophils increased 2.3-fold over baseline after E(2) treatment (P = 0 .0008 us. placebo). The mean coefficients of variation for the intrasu bject (day to day) and intersubject variability of circulating AMs wer e between 5.4-7.5% and 20-29%, respectively. Our findings indicate tha t the effect of E(2) on circulating AMs is not distinguishable from th e intrasubject variability observed after placebo treatment. Thus, an effect of E(2) On adhesion molecules is unlikely to contribute to the antiatherogenic-cardioprotective effect of E(2) The pronounced E(2)-me diated increase in neutrophils deserves further studies to elucidate i ts (patho-)physiological implications.