title: Circadian relationships between circulating atrial natriuretic peptides and serum calcium and phosphate in healthy humans.
abstract: Long-acting natriuretic peptide (LANP), vessel dilator (VSDL), and atrial natriuretic factor (ANF) consisting of amino acids (aa) 1 to 30, 31 to 67, and 99 to 126, respectively, of the 126-aa ANF prohormone circulate in humans. Among the biologic properties of these peptides is the ability of ANF to decrease intracellular calcium concentrations. To determine if atrial natriuretic peptides are directly related to serum calcium and/or phosphate in healthy normocalcemic humans, we examined 21 24-hour profiles of VSDL, LANP, ANF, and serum calcium and phosphate in 14 healthy humans. VSDL, LANP, and ANF each had significant (P < .001) circadian rhythms, with peak concentrations late during sleep (at 4:00 AM) being nearly twice the concentrations in the afternoon and evening. Serum calcium and phosphate also had significant circadian rhythms (P < .001) with troughs nearly opposite to those of the atrial natriuretic peptides, suggesting that atrial peptides may be important in the modulation of the circadian rhythms of calcium and phosphate. The nearly identical circadian rhythms of the atrial natriuretic peptides and of parathyroid hormone (PTH) reported by others, along with evidence that PTH may increase atrial peptide release, suggest that some of the effects attributed to PTH may be mediated by atrial natriuretic peptides.
authors.affiliation: Department of Internal Medicine, University of South Florida Health Sciences Center, Tampa, USA.
authors.forename: D L
authors.initials: DL
authors.lastname: Vesely
authors.forename: R B
authors.initials: RB
authors.lastname: Sothern
authors.forename: L E
authors.initials: LE
authors.lastname: Scheving
authors.forename: F W
authors.initials: FW
authors.lastname: Bremner
authors.forename: J L
authors.initials: JL
authors.lastname: Third
authors.forename: J B
authors.initials: JB
authors.lastname: McCormick
authors.forename: S
authors.initials: S
authors.lastname: Dawson
authors.forename: S
authors.initials: S
authors.lastname: Kahn
authors.forename: G
authors.initials: G
authors.lastname: Augustine
authors.forename: M
authors.initials: M
authors.lastname: Ryan
authors.forename: J
authors.initials: J
authors.lastname: Greco
authors.forename: B A
authors.initials: BA
authors.lastname: Nemchausky
authors.forename: P
authors.initials: P
authors.lastname: Shirazi
authors.forename: E L
authors.initials: EL
authors.lastname: Kanabrocki
mesh_terms: D000328:Adult; D000368:Aged; D009320:Atrial Natriuretic Factor / Q000097:blood*; D002118:Calcium / Q000097:blood*; D002940:Circadian Rhythm; D006801:Humans; D008297:Male; D008875:Middle Aged; D010446:Peptide Fragments / Q000097:blood; D010710:Phosphates / Q000097:blood*; D011498:Protein Precursors / Q000097:blood; D012016:Reference Values
chemical_list: D010446:Peptide Fragments; D010710:Phosphates; D011498:Protein Precursors; C054547:atrial natriuretic factor prohormone (1-30), human; C054548:atrial natriuretic factor prohormone (31-67); D009320:Atrial Natriuretic Factor; D002118:Calcium