Effects of physiological doses of atrial natriuretic peptide on lipolysis, ketogenesis, and glucose metabolism in men

Background: Atrial natriuretic peptide (ANP) is secreted from the heart and the circulating concentrations increases during an acute bout of exercise. ANP is suggested to stimulate lipolysis, which has been demonstrated administering supraphysiological doses of ANP to humans. However, it is not known whether an acute increase in circulating ANP within the physiological range affects lipolysis in healthy humans, and thereby play a role in mobilisation of energy in healthy humans. Objective: To determine the effects of physiological doses of ANP on lipolysis, ketogenesis, and glucose metabolism in resting, healthy men. Methods: Ten healthy men were randomised to a one-hour infusion of ANP versus placebo in a cross-over design while infused with the stable isotopes: [1,1,2,3,3-D 5 ]-glycerol, potassium- 13 C 16 ]-palmitate, sodium-D-β-[2,4- 13 C 2 ]-hydroxybutyrate, and [6,6-D 2 ]-glucose to determine changes in rate of appearance and disappearance of glycerol, palmitate, β-hydroxybutyrate, and glucose. Results: Plasma ANP concentration increased from 2.8 pmol/L to a peak of 11.1 pmol/L with ANP infusion. This was compiled by an increase in the plasma concentration of the secondary messenger, 3',5'-cyclic guanosinemonophosphat (cGMP), from 6.5 nmol/L to 12.5 nmol/L. No effects of ANP infusion were observed in the rate of appearance and rate of disappearance of glycerol, palmitate, β-hydroxybutyrate, or glucose. The blood volume and blood pressure remained unaffected during the study. Conclusion: In the present study physiological doses of ANP had no effect on lipolysis, ketogenesis, and glucose metabolism in healthy men. The lipid turn-over does, therefore, not seem to be regulated by ANP in healthy individuals.