CONICET | Buscador de Institutos y Recursos Humanos

Introduction: Changes in von Willebrand factor (VWF) during human pregnancy had been related to hormonal control. Following the studies of normal mice VWF levels, we hypothesize that the hormonal treatment could modulate the VWF plasmatic in BALB-C mice. Methods: The protocol of treatment was: A: oral 17â-estradiol (E2), Sigma, 500 µg/mouse/d, n=24; B: E2 + fulvestrant (anti-E2), Astra-Zeneca, 500 µg/mouse/d, n=5; C: anti-E2, n=3; D: s.c. progesterone (P4), Sigma, 2 mg/mouse/d, n= 4; E: E2+P4, n=4; F: controls: oral/s.c.vehicles (0.1 ml/ mouse), n=17; G: i.p. LPS, Sigma, 50 µg/mouse in saline, n=6. All treatments were performed for 2 days. Mice were bled by cardiac puncture after 24 hs of treatment. The mice treated with g (positive control) were bled at 6 hours post therapy. The experiments were designed to compare: I- A with F and G; II- A, B, C, F, G; III- A, D, E, F, G. Plasmatic VWF:Ag was determined in each sample. </s4><s5> Results: I- No increase in VWF:Ag was observed after treatment A compare to F (14.8±5 vs. 12.9±4, p=ns). II- The treatment with A (13.9±5), B (10.6±4) or C (14.8±3), not affected the levels of VWF:Ag, with no differences compare with F (12.2±4)(p=ns). III- The levels of VWF:Ag after treatment D (8.6±3), remained without changes compared with A (11.4±4) and F (8.5±1.4)(p=ns). Overlapping D to A (e: 7.2±3) not induced changes. Mice treated with g increased plasmatic VWF:Ag (20.7±1.4), and were significantly higher than all other treatments: A <0,001, B 0.004, C 0.004, D 0.009, E 0.009, F 0.02. Conclusions: Mice failed to respond to hormones, even though the doses were supraphysiological. Although murine VWF respond to stimuli such as LPS, steroid hormones can not induce detectable changes in short term experiments.