EFFECTS OF 17-BETA-ESTRADIOL ON CIRCULATING ADHESION MOLECULES

The effects of 17 beta-estradiol (E(2)) On the serum levels of the circulating endothelial-leukocyte, intercellular, and vascular adhesion molecules [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, and surface expression of the lymphocyte function-associated antigen-1 (CD11a/CD18), CD3, CD4, CD19, and CD25 on leukocytes was studied in another group of volunteers. A 5% decrease in circulating ICAM-1 (P = 0.045 vs. placebo) was found when a single time point (96 h after E(2) injection) was studied. However, this decrease was smaller than the intrasubject (day to day) variability observed, and there was no consistent and time-dependent effect of E(2) On circulating AMs. Circulating neutrophils increased 2.3-fold over baseline after E(2) treatment (P = 0.0008 us. placebo). The mean coefficients of variation for the intrasubject (day to day) and intersubject variability of circulating AMs were between 5.4-7.5% and 20-29%, respectively. Our findings indicate that the effect of E(2) on circulating AMs is not distinguishable from the 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)-mediated increase in neutrophils deserves further studies to elucidate its (patho-)physiological implications.