E P Schröder | PubMed Health

PubMed1995

Increased prostacyclin production during exercise in untrained and trained men: effect of low-dose aspirin.

The influence of a submaximal exercise on urinary 2,3-dinor-6-ketoprostaglandin F1 alpha (2,3-dinor-6-keto-PGF1 alpha), 2,3-dinor-thromboxane B2 (2,3-dinor-TxB2), and prostaglandin E2 excretion and on platelet aggregation was compared in untrained and trained subjects before and after low-dose aspirin administration (50 mg/day, 7 days). 2,3-Dinor-TxB2 excretion was significantly higher in the athletes at rest (P < 0.05). Submaximal exercise selectively increased 2,3-dinor-6-keto-PGF1 alpha excretion without affecting 2,3-dinor-TxB2 or prostaglandin E2 excretion rates or platelet aggregation. Low-dose aspirin inhibited platelet aggregation and 2,3-dinor-TxB2 excretion but reduced 2,3-dinor-6-keto-PGF1 alpha by only 24% in the untrained and by 51% in the trained subjects (P < 0.05). After low-dose aspirin administration, the selective stimulatory effect of submaximal exercise on urinary 2,3-dinor-6-keto-PGF1 alpha excretion was even more pronounced than before. The ratio of 2,3-dinor-6-keto-PGF1 alpha to 2,3-dinor-TxB2 was increased by exercise; this effect was significantly enhanced by low-dose aspirin (P < 0.05). Our results suggest that the stimulatory effect of submaximal exercise on prostacyclin production is mostly due to an activation of prostacyclin synthesis from endogenous precursors rather than the result of an enhanced endoperoxide shift from activated platelets to the endothelium. This effect is potentiated by low-dose aspirin pretreatment, indicating that 50 mg/day of aspirin do not impair exercise-induced endothelial prostacyclin production.

6-Ketoprostaglandin F1 alpha↗

PubMed1994

Exercise increases systemic nitric oxide production in men.

BACKGROUND: Our aim was to compare the effects of exercise on systemic nitric oxide formation, assessed from the urinary excretion rates of nitrate and of cyclic GMP, in endurance-trained and untrained men. METHODS: Ten endurance-trained and six untrained men underwent a submaximal exercise test for 30 min at 60% of their individual maximal work capacity. Urinary excretion rates of nitrate (measured using gas chromatography) and cyclic GMP (measured using a radioimmunoassay) were assessed at hourly intervals. RESULTS: Urinary nitrate excretion was comparable at rest in the two groups (104 +/- 35 and 110 +/- 19 mumol/mmol creatinine; NS), more than doubled during exercise in both groups (236 +/- 88 mumol/mmol creatinine in untrained and 252 +/- 39 mumol/mmol creatinine in trained participants; P < 0.01 for both groups) and decreased rapidly after the completion of the exercise test. Excretion of urinary cyclic GMP at rest was four times higher in the endurance-trained than in the untrained men (21 +/- 5 compared with 6 +/-1 nmol/mmol creatinine; P < 0.05). During the exercise test, GMP excretion approximately doubled in both groups (52 +/- 12 and 10 +/- 1 nmol/mmol creatinine, respectively; P < or = 0.01 for both groups) and returned to baseline at the end of the test. Urinary cyclic GMP and nitrate excretion correlated well in both groups (p < 0.05). Atrial natriuretic factor is also a stimulator of cyclic GMP formation but resting plasma levels of atrial natriuretic factor did not differ between the groups (22 +/- 3 compared with 21 +/- 4 pmol/l; NS). CONCLUSION: An acute submaximal exercise test increases the formation of nitric oxide, reflected in the increase in urinary excretion of nitrate and cyclic GMP. This increase may contribute to vasodilatation during physical exercise and at least partly explain the beneficial effects of physical training in patients with vascular diseases.

Adult↗