title: Atrial natriuretic peptide--the influence of various physiological and sampling conditions.
abstract: A study of various physiological conditions, possibly influencing levels of atrial natriuretic peptide (ANP), is described. Atrial natriuretic peptide was determined by a radioimmunoassay, suitable for routine measurements, using 1 mL of human plasma. Atrial naturetic peptide was adsorbed onto Sep-pak C-18 cartridges, eluted with acidified ethanol and subsequently radioimmunoassayed. The detection limit was slightly less than 2 pg/tube (approximately 5 pg/mL plasma). Intra- and interassay coefficients of variation were 7 and 10%, respectively. Study of various sampling conditions revealed that blood sampling in EDTA-tubes kept on ice, and centrifuged within 1 h, gives the most reliable results. Reference values in 74 individuals ranged between 10 to 69 pg/mL (mean +/- SD = 30 +/- 11 pg/mL). We observed no difference in reference values when the blood sampling procedure was in the sitting (29 +/- 11 pg/mL, n = 43) or supine (31 +/- 12 pg/mL, n = 31) position. Venepuncture stress did not consistently change ANP-levels. No difference was observed in ANP between the follicular and the luteal phase of the menstrual cycle. ANP levels of 7 ambulant female subjects declined significantly during the study period from 7 a.m. to 3 p.m.
mesh_terms: D000328:Adult; D009320:Atrial Natriuretic Factor / Q000097:blood*; D001800:Blood Specimen Collection / Q000379:methods; D002940:Circadian Rhythm; D005260:Female; D006801:Humans; D008297:Male; D008597:Menstrual Cycle; D011187:Posture; D011247:Pregnancy; D011863:Radioimmunoassay
chemical_list: D009320:Atrial Natriuretic Factor