Increase in plasma atrial natriuretic polypeptide (ANP) following sodium load in anesthetized rats.
To investigate the releasing mechanisms of atrial natriuretic polypeptide (ANP), identical amounts of 5% glucose solution, isotonic (0.9%) or hypertonic (5%) saline were infused intravenously for 5 min (2 ml/min) in anesthetized rats. At the same time, plasma immunoreactive ANP (ir-ANP) was measured using a direct radioimmunoassay. Plasma ir-ANP increased after infusion of 5% glucose solution (P less than 0.01) and isotonic saline (P less than 0.05), and returned rapidly to the basal levels in the recovery period. Plasma ir-ANP increased to a greater degree in the group infused with hypertonic saline than in the other two groups. The major immunoreactive component of increased ir-ANP was identified as alpha-rat ANP, a 28 amino acid residue, by using reverse phase high-performance liquid chromatography. These results suggest that sodium ions may be a stimulating factor of ANP release as well as volume expansion.
D000818:Animals; D009320:Atrial Natriuretic Factor / Q000097:blood*; D001810:Blood Volume / Q000187:drug effects; D002851:Chromatography, High Pressure Liquid; D006801:Humans; D008297:Male; D009318:Natriuresis / Q000187:drug effects; D011863:Radioimmunoassay; D051381:Rats; D011919:Rats, Inbred Strains; D012462:Saline Solution, Hypertonic / Q000494:pharmacology*; D012965:Sodium Chloride / Q000494:pharmacology*
D012462:Saline Solution, Hypertonic; D012965:Sodium Chloride; D009320:Atrial Natriuretic Factor