Cardiovascular pharmacology In vivo profile of the anticoagulant effect of 17ß-amino-1,3,5(10)estratrien-3-ol Cristina Lemini a,n , Consuelo Rubio-Po ´o b , Yanira Franco a , Ruth Jaimez a , Marı ´a Estela Avila a , Martha Medina a , Ana Elena Lemus c,d a Departamento de Farmacologı ´a, Facultad de Medicina, UNAM. Av. Universidad No. 3000, Ciudad Universitaria, Colonia Copilco Universidad, Delegacio ´n Coyoaca ´n, Mexico DF, CP 04360, Mexico b Facultad de Estudios Superiores Zaragoza, UNAM, Mexico c Departamento de Biologı ´a de la Reproduccio ´n, Universidad Auto ´noma Metropolitana-Iztapalapa, Mexico DF, CP 09340, Mexico d Departamento de Biologı ´a de la Reproduccio ´n, ‘‘Dr. Carlos Gual Castro’’, Instituto Nacional de Ciencias Me ´dicas y Nutricio ´n Salvador Zubira ´n. CP14000, Mexico article info Article history: Received 11 July 2012 Received in revised form 7 December 2012 Accepted 18 December 2012 Available online 7 January 2013 Keywords: 17b-aminoestrogen 17b-aminoestrol Estradiol Blood clotting time Mouse abstract The anticoagulant activity of 17ß-amino-1,3,5(10)estratrien-3-ol (AE 2 ) was established for the first time. Experiment 1: mice groups were treated with a single subcutaneous (s.c.) AE 2 injection (0.5, 1, 2, 4, and 8 mg/100 g BW) or vehicle (propylenglycol; 0.5 ml/100 g). After 24 h, AE 2 produced dose- dependent blood clotting time increases related to control, Emax ¼þ121% (P o0.01) finishing the sixth day. Experiment 2: four groups received a single s.c. administration of AE 2 (4 or 8 mg/100 g BW) or 17ß-estradiol (E 2 ; 3 mg/100 g BW) or vehicle. After 24 and 48 h post-administration, the times of blood clotting, prothrombin, thrombin, and activated partial thromboplastin and fibrinogen concentrations were assessed. Both AE 2 doses increased blood clotting and fibrinogen similarly, blood clotting time: 64, 94%; fibrinogen: 71, 107% (P o0.01). Prothrombin, activated partial thromboplastin and thrombin times, increased 13–15%, 27–55%, and 15–29%, respectively (P o0.01). Meanwhile E 2 decreased blood clotting 20% (P o0.01) and thrombin 23% (P o0.01) after 48 h. Experiment 3: for five consecutive days, mice received AE 2 or E 2 (0.1, 1, 10, 100, and 1000 mg/kg/day), or vehicle. Blood clotting time was assessed at 1, 2, 3, 4, 5, 8, and 11 days after treatment. AE 2 at all doses were anticoagulant for 2–3 days after administration whereas E 2 was procoagulant for 8–11 days. These opposite effects were: AE 2 Emax ¼þ29%; E 2 Emax ¼ 30%; (P o0.01). AE 2 is the parent compound of the 17ß-aminoestrogens, with the largest and longest anticoagulant effect until now reported. & 2012 Elsevier B.V. All rights reserved. 1. Introduction Premenopausal women have lower incidence of cardiovascular disease compared with age-matched men (Hayward et al., 2000). This protection is mainly attributed to estrogens modulating action on lipid metabolism, vasculature, inflammation and blood coagulation processes (Guetta and Cannon, 1996; Cushman, 2002). During menopause, estrogen production decreases and meno- pausal hormone therapy (MHT) is often prescribed, which is associated with an increased risk of venothrombotic episodes, (van Hylckama Vlieg et al., 2009; Canonico et al., 2010). Estrogen therapy increases coagulation factors, decreases nat- ural anticoagulants activity and those involved in fibrinolysis (van Hylckama Vlieg and Rosendaal, 2003; Gotts ¨ ater et al., 2001). These alterations in the hemostatic balance may lead to a hypercoagulability state, favoring thrombogenesis (Rosendaal et al., 2001). Individualized MHT is recommended considering the patient’s risk factors and prescribing the lowest effective dose for the shortest possible duration (Santen et al., 2010). In our search for alternative estrogens without thromboem- bolic risk, we have evaluated several 17ß-aminoestrogens in rodents. These compounds produce anticoagulant effects that contrast with the procoagulant effects elicited by estradiol (E 2 ) (Rubio-Po ´ o et al., 1985, Lemini et al., 2005a). Prodiame was the first AE reported as an anticoagulant, which possesses a diamino group substituent (–NH–CH 2 CH 2 –CH 2 –NH 2 ) on C17b of the ster- oid molecule (Rubio-Po ´ o et al., 1983). Prodiame increased blood clotting times in mice, however higher doses produced a con- vulsive effect (Mandoki et al., 1991). Structural changes on the terminal amino group substituent in prodiame  s molecule led to prolame (–CH 2 –NH–CH 2 CH 2 –OH), buame (–NH–CH 2 CH 2 –CH 2 – CH 3 ), which retained the anticoagulant activity, and proacame (–NH–CH 2 CH 2 –CH 2 –COOH), which inhibited it (Mandoki et al., 1991). Contents lists available at SciVerse ScienceDirect journal homepage: www.elsevier.com/locate/ejphar European Journal of Pharmacology 0014-2999/$ - see front matter & 2012 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.ejphar.2012.12.030 n Correspondence to: Departamento de Farmacologı ´a, Facultad de Medicina, UNAM, Ciudad Universitaria, CP 04360, Apartado Postal 70-297, Mexico City, Mexico. Tel.: þ52 55 5623 2177; fax: þ52 55 5616 1489. E-mail address: clemini@unam.mx (C. Lemini). European Journal of Pharmacology 700 (2013) 210–216