Abstract
Plasma concentrations of pro-Atrial natriuretic peptide, proANP, are decreased in obesity and diabetes. Decreased proANP concentrations have also been noted after meal intake, and recently, a glucose-mediated regulation of ANP gene expression was reported. Hence, we evaluated the effects of insulin, glucagon and glucose on plasma proANP in a series of observational and experimental studies. Six healthy men underwent seven days of bed rest. Before and after the bed rest, hyperinsulinemic euglycemic clamps with serial plasma measurements of proANP were performed. Moreover, plasma proANP was quantified in 65 individuals with normal or impaired glucose regulation. Finally, the effects of infusion-induced hyperglucagonemia were examined in ten healthy men. Bed rest decreased insulin sensitivity and plasma proANP. The decrease in proANP was not associated with insulin sensitivity and the peptide concentrations remained constant during euglycemic hyperinsulinemia and hyperglycemic hyperglucagonemia. Impaired glucose regulation was not associated with decreased proANP concentrations. Bed rest per se induces a marked decrease in plasma proANP concentrations whereas insulin resistance and impaired glucose regulation was not associated with lower proANP concentrations. Neither acute hyperinsulinemia nor hyperglucagonemia seems to affect plasma proANP. Our findings thus suggest that decreased plasma proANP concentrations occur late in the development of insulin resistance.