title: Ovariectomy and estradiol replacement therapy alters the adenine nucleotide hydrolysis in rat blood serum.
abstract: The low prevalence of coronary heart disease in premenopausal women and its increase after menopause are well established. Many studies have suggested that steroid hormones can inhibit platelet aggregation, reducing the cardiovascular risk. In addition, a number of studies have shown an effect of estrogen on vascular function. The process of haemostasis and thrombus formation can be also affected by adenine nucleotides and adenosine. Consequently, the regulation of enzymes that hydrolyze these nucleotides in the bloodstream is essential in the modulation of the processes of platelet aggregation, vasodilatation and coronary flow. Thus, in this study, we examined the effect of ovariectomy (OVX), estradiol replacement therapy and the in vitro administration of 17beta-estradiol, dehydroisoandrosterone 3-sulfate (DHEAS) and pregnenolone (PREG) on the activity of the enzymes that degrade adenosine triphosphate (ATP), adenosine diphosphate (ADP) and adenosine monophosphate (AMP) in the blood serum of female rats. OVX significantly increased the hydrolysis of ATP, ADP and AMP, whilst phosphodiesterase activity was unchanged. Estradiol replacement therapy significantly decreased the hydrolysis of the adenine nucleotides and of the substrate marker of phosphodiesterase. In vitro, the addition of steroid hormones did not have any effect on the nucleotide hydrolysis by rat serum. These results suggest the presence of a strong relation between these enzymes and the hormonal system. In addition, the alterations observed are important, because these enzymes control the nucleotides/nucleosides ratio in the circulation and thus the events related to haemostasis.
authors.affiliation: Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Avenida Ramiro Barcellos, 2600-ANEXO, 90035-003 Porto Alegre, RS, Brazil.
authors.forename: Daniela
authors.initials: D
authors.lastname: Pochmann
authors.forename: Bárbara
authors.initials: B
authors.lastname: Rücker
authors.forename: Ana M O
authors.initials: AM
authors.lastname: Battastini
authors.forename: João J F
authors.initials: JJ
authors.lastname: Sarkis
mesh_terms: D015720:5'-Nucleotidase / Q000378:metabolism; D000227:Adenine Nucleotides / Q000097:blood / Q000378:metabolism*; D000244:Adenosine Diphosphate / Q000378:metabolism; D000249:Adenosine Monophosphate / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001081:Apyrase / Q000378:metabolism; D019314:Dehydroepiandrosterone Sulfate / Q000494:pharmacology; D004958:Estradiol / Q000494:pharmacology; D005260:Female; D012739:Gonadal Steroid Hormones / Q000494:pharmacology; D020249:Hormone Replacement Therapy; D006868:Hydrolysis; D010052:Ovariectomy; D011280:Pregnanolone / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar
chemical_list: D000227:Adenine Nucleotides; D012739:Gonadal Steroid Hormones; D000249:Adenosine Monophosphate; D004958:Estradiol; D019314:Dehydroepiandrosterone Sulfate; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D011280:Pregnanolone; D015720:5'-Nucleotidase; D001081:Apyrase