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Role of atrial natriuretic peptide in hemoconcentration during exercise
R C Tsai1, T Yamaji, M Ishibashi
1Third Department of Internal Medicine, Faculty of Medicine, University of Tokyo, Japan.
Insights
This study found that atrial natriuretic peptide (ANP) levels correlate with blood hematocrit (Hct) changes during exercise. Beta-blockade with propranolol amplified these effects, suggesting ANP influences exercise-induced hemoconcentration.
Area of Science:
- Exercise Physiology
- Cardiovascular Endocrinology
Background:
- Atrial natriuretic peptide (ANP) plays a role in cardiovascular regulation.
- Exercise induces physiological changes, including fluid shifts and hematocrit alterations.
Purpose of the Study:
- To investigate the relationship between plasma ANP levels and hematocrit (Hct) during treadmill exercise.
- To examine the effects of beta-adrenergic blockade on ANP, Hct, and albumin during exercise.
Main Methods:
- Six healthy men underwent treadmill exercise testing.
- Plasma ANP, albumin, and Hct were measured before, during, and after exercise.
- Measurements were taken both without and after 3 days of propranolol administration.
Main Results:
- Plasma ANP increased during exercise, with a positive correlation to Hct changes.
- Propranolol significantly elevated basal ANP and Hct levels, further increasing Hct during exercise.
- A significant positive correlation between ANP and Hct increments persisted after propranolol.
Conclusions:
- Plasma ANP levels are closely related to exercise-induced hemoconcentration.
- ANP may be a contributing factor to the hemoconcentration observed during physical activity.
- Beta-adrenergic blockade influences ANP release and hemoconcentration during exercise.
Abstract:
Changes in plasma levels of atrial natriuretic peptide (ANP) and albumin, and blood hematocrit (Hct) during treadmill exercise were studied in 6 healthy men before and after beta-adrenergic blockade. Plasma ANP levels increased during exercise and then gradually decreased. There was a concomitant increase in both Hct and plasma albumin concentrations. Prior administration of a long-acting propranolol, 160 mg daily for 3 consecutive days, markedly elevated plasma ANP levels before, during and after exercise. In addition, the mean basal Hct increased significantly and further rose during exercise after propranolol administration. When increments in plasma ANP concentrations during exercise in individual subjects were compared with those in Hct, there was a significant positive correlation between the two variables before and after propranolol administration. The results indicate a close relationship between the changes in plasma ANP and those in Hct during exercise at different ANP levels, and suggest that ANP may be at least one of the factors involved in the hemoconcentration associated with exercise.