title: Ecto-hydrolysis of adenine nucleotides in rat blood platelets are altered by ovariectomy.
abstract: There is evidence that estrogen is associated with a reduction on cardiovascular disease risk through inhibition of platelet aggregation and action on vascular function. The process of haemostasis can also be affected by adenine nucleotides and adenosine. Consequently, 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. Ecto-ATP diphosphohydrolase and ecto-5'-nucleotidase from platelets are enzymes related to nucleotide hydrolysis. In the present study, we examined the effect of ovariectomy (OVX) and estradiol replacement therapy (ER) on the activity of the enzymes that degrade adenine nucleotides in platelets of female rats. The OVX group significantly decrease the hydrolysis of ATP, ADP and AMP by 42, 52 and 29.3%, respectively, when compared to a control group. ER did not reverse the inhibition of nucleotide hydrolysis observed in OVX rats. Our findings indicate that hormonal deprivation affects ATP, ADP and AMP hydrolysis by platelets and consequently the level of these nucleotides and adenosine in the circulation. Since, ADP is the most important platelet agonist and recruiting agent present in the microenvironment of the thrombus, our findings was contribute to a better comprehension of the cardiovascular complications described in alterations of sexual hormonal status.
authors.affiliation: Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
authors.forename: Daniela
authors.initials: D
authors.lastname: Pochmann
authors.forename: Ana Elisa
authors.initials: AE
authors.lastname: Böhmer
authors.forename: Alessandra
authors.initials: A
authors.lastname: Nejar Bruno
authors.forename: João J F
authors.initials: JJ
authors.lastname: Sarkis
mesh_terms: D015720:5'-Nucleotidase / Q000378:metabolism; D000227:Adenine Nucleotides / Q000378:metabolism*; D000241:Adenosine / Q000378:metabolism; D000244:Adenosine Diphosphate / Q000378:metabolism; D000249:Adenosine Monophosphate / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D015703:Antigens, CD / Q000378:metabolism; D001081:Apyrase / Q000378:metabolism; D001792:Blood Platelets / Q000201:enzymology / Q000378:metabolism*; D002462:Cell Membrane / Q000201:enzymology / Q000378:metabolism; D004789:Enzyme Activation; D015914:Estrogen Replacement Therapy / Q000009:adverse effects*; D005260:Female; D006868:Hydrolysis; D010052:Ovariectomy / Q000009:adverse effects*; D051381:Rats; D017208:Rats, Wistar
chemical_list: D000227:Adenine Nucleotides; D015703:Antigens, CD; D000249:Adenosine Monophosphate; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D015720:5'-Nucleotidase; D001081:Apyrase; C067869:CD39 antigen; D000241:Adenosine