Sex-specific changes in platelet aggregation and secretion with sexual maturity in pigs

Cardiovascular disease may begin early in adolescence. Platelets release factors contributing to vascular disease. Experiments were designed to test the hypothesis that hormonal transitions associated with sexual maturity differentially affect platelet aggregation and secretion in males and females. Platelets were collected from juvenile (2–3 mo) and sexually mature (adult; 5–6 mo) male and female pigs (n = 8/group). Maturation was evidenced by increased weight of reproductive tissue and changes in circulating levels of gonadal hormones. Aggregation to ADP (10 μM) and collagen (6 μg/ml) and ATP secretion to 50 nM thrombin were determined by turbidimetric analysis and bioluminescence, respectively. Total platelet counts, platelet turnover, and mean platelet volume did not change with maturity. Platelet aggregation and ATP secretion decreased in females but increased in males with maturity, whereas total ATP content remained unchanged in platelets from females but increased in platelets from males. Platelet...