RESUMO
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=+121% (P<0.01) finishing the sixth day. Experiment 2: four groups received a single s.c. administration of AE(2) (4 or 8 mg/100g BW) or 17ß-estradiol (E(2); 3mg/100g 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<0.01). Prothrombin, activated partial thromboplastin and thrombin times, increased 13-15%, 27-55%, and 15-29%, respectively (P<0.01). Meanwhile E(2) decreased blood clotting 20% (P<0.01) and thrombin 23% (P<0.01) after 48 h. Experiment 3: for five consecutive days, mice received AE(2) or E(2) (0.1, 1, 10, 100, and 1000 µg/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=+29%; E(2) Emax=-30%; (P<0.01). AE(2) is the parent compound of the 17ß-aminoestrogens, with the largest and longest anticoagulant effect until now reported.
Assuntos
Anticoagulantes/farmacologia , Estradiol/análogos & derivados , Estrenos/farmacologia , Animais , Coagulação Sanguínea/efeitos dos fármacos , Testes de Coagulação Sanguínea , Relação Dose-Resposta a Droga , Estradiol/farmacologia , Fibrinogênio/metabolismo , Masculino , CamundongosRESUMO
INTRODUCTION: Rats and mice have been used to evaluate effects of natural and synthetic oestrogens. However, data about oestrogen's effects on haemostasis in rodents is very limited. The aim of this work was to standardize blood coagulation screening tests in adult male, female, and ovariectomized (Ovx) Wistar rats and CD1 mice in an effort to evaluate the influence of gender and species differences on haemostasis. MATERIALS AND METHODS: Values were obtained for the following haemostatic parameters: prothrombin time (PT), activated partial thromboplastin time (aPTT), thrombin clotting time (TT), and fibrinogen (FIB), through modifications of the conventional techniques used for human blood coagulation analysis. RESULTS: Both rats and mice showed gender intra-species and inter-species differences of high significance in PT, aPTT, TT, and FIB values. Intra-species differences were found in TT (+10% p<0.01) and FIB concentration (-21% p<0.001) between male and Ovx rats. Male vs. Ovx mice showed a TT difference of -20% (p<0.001). The main inter-species differences found were PT values of male rats vs. male mice (-39%) and female rats vs. female mice (-35%, both p<0.001). Female rats and mice aPTT values vs. those corresponding to Ovx animals showed differences of +15% and +32% (p<0.001), respectively. CONCLUSIONS: These data reveal the great importance of gender intra- and inter-species differences on the values of haemostatic screening tests, which should be taken into consideration when evaluating the effects of oestrogens and other drugs on the coagulation system.
Assuntos
Fibrinogênio/análise , Tempo de Tromboplastina Parcial , Tempo de Protrombina , Animais , Testes de Coagulação Sanguínea/métodos , Feminino , Masculino , Camundongos , Camundongos Endogâmicos , Ovariectomia , Ratos , Ratos Wistar , Fatores Sexuais , Especificidade da Espécie , Tempo de TrombinaRESUMO
Estrogens have been associated with thromboembolic events. Our group has described the anticoagulant effect of 17 beta-aminoestrogens in rodents, potentially new alternative estrogenic agents without thrombogenic risk. This work compares the contrasting effects of estradiol and the 17 beta-aminoestrogens (prolame, butolame, and pentolame) on blood clotting time. Ovariectomized CD1 mice received a single injection of 17beta-aminoestrogens, estradiol (20 to 80 mg/kg), or vehicle. Estradiol decreased blood clotting time from -10% to -25% (48 h; P<0.01) and 17 beta-aminoestrogens increased it, differing in latency (approximately 12 h; +48%, P<0.01) and duration (approximately 72 h +58%, P<0.01). In male Wistar rats, similar effects (pentolame +45%; estradiol -31%; P<0.01) were observed 48 h after five consecutive daily injections of 1000 microg/animal/day. The maximum procoagulant effect of estradiol was obtained after 72 h with 10 microg/animal/day (-45%; P<0.01). 17 Beta-aminoestrogens always produced opposite effects to those of estradiol on blood coagulation.
Assuntos
Coagulação Sanguínea/efeitos dos fármacos , Congêneres do Estradiol/farmacologia , Estradiol/farmacologia , Amino Álcoois/farmacologia , Animais , Relação Dose-Resposta a Droga , Estradiol/administração & dosagem , Congêneres do Estradiol/administração & dosagem , Estrenos/administração & dosagem , Estrenos/farmacologia , Feminino , Masculino , Camundongos , Ovariectomia , Ratos , Ratos WistarRESUMO
Administration of exogenous estrogens has been associated with an increase of thromboembolic events. The 17 beta-aminoestrogens produce anticoagulant effects contrasting with the procoagulant effects of the natural occurring estradiol in rodents. This work compares the estrogenic effects induced by 17 beta-aminoestrogens prolame, butolame, pentolame, and estradiol in vivo models. Dose-response curves were performed using immature CD1 mice and Wistar rats. The animals were injected with estradiol or 17 beta-aminoestrogens (0.01 to 1000 microg/kg), or vehicle. The uterine wet and dry weights were determined. The 17 beta-aminoestrogens increased uterine weight in a dose-dependent manner. The uterotrophic effect produced by estradiol induced lower ED50 (6.5 and 4 microg/kg) and higher E(max) values (+523-350%) in mice as compared with those from the rat, indicating more susceptibility of the mice model. The 17 beta-aminoestrogens are partial estrogenic agonists with a relative uterotrophic effect of estradiol (100%) from 9-86%. Only the ED50 values of 17 beta-aminoestrogens in CD1 mice showed a direct correlation to the length of the amine group substitution in C-17 since their efficacy and potency were in the order: prolame>butolame>pentolame.
Assuntos
Congêneres do Estradiol/farmacologia , Útero/efeitos dos fármacos , Amino Álcoois/administração & dosagem , Amino Álcoois/farmacologia , Animais , Relação Dose-Resposta a Droga , Estradiol/administração & dosagem , Estradiol/farmacologia , Congêneres do Estradiol/administração & dosagem , Estrenos/administração & dosagem , Estrenos/farmacologia , Feminino , Camundongos , Tamanho do Órgão/efeitos dos fármacos , Ratos , Ratos Wistar , Útero/anatomia & histologiaRESUMO
Oral contraceptives containing estrogens increases the incidence of thromboembolic events. In contrast, administration of 17beta-aminoestrogens prolonged blood clotting time (BCT) in rodents. We studied the effect of estradiol (E(2)), ethinylestradiol (EE) and pentolame on some screening hemostatic tests. BCT was evaluated 24, 48, 72 and 96 h post-treatment. Rats received subcutaneously (s.c.) for five consecutive days E(2) (0.1-1000 microg), EE (1-1000 microg), pentolame (0.1-1000 microg), or vehicle (propyleneglycol 0.3 ml). At 48 h post-treatment E(2) (1000 microg) diminished BCT (32%, P<0.01), in contrast pentolame (1000 microg) augmented BCT by 41% (P<0.01). After 72 h, E(2) showed procoagulant effects with 10, 100 and 1000 microg doses (-45, -30, and -21%, respectively). Significant effects on BCT of EE were observed 72 h after with 1000 microg (-12%, P<0.05). Animals were treated s.c. for two consecutive days with E(2) (3mg/100g), pentolame (4 mg), or vehicle (0.1 ml). BCT, bleeding time (BT), platelet aggregation (PA), prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT) and fibrinogen concentration were determined. E(2) produced a significant diminution on BCT (-20%) after 72 h whereas pentolame increased BCT from 24 to 96 h (62%, maximal response at 48 h). APTT and PT coagulation times of the groups treated with E(2) and pentolame were lengthened (33 and 29%; 16 and 24%, respectively; P<0.05). Fibrinogen concentration increased (115%, P<0.01) only in the pentolame-treated group. Pentolame and E(2) produced any effects on BT and PA compared with control groups, indicating that platelet function was not modified. Our results indicate that E(2), EE and pentolame affects the plasmatic phase of the hemostatic mechanism.