The circadian rhythm of the N-terminus and C-terminus of the atrial natriuretic factor prohormone.
Circadian variation in the circulating concentrations of the N-terminal and C-terminal portions of the atrial natriuretic factor prohormone (pro ANF) was evaluated in 8 men, ages 41-47, who have been followed for 19 years with respect to circadian variation in physiological variables including blood pressure and clinical chemistries. The N-terminus of the ANF prohormone contains two peptides consisting of amino acids 1-30 and 31-67 while the C-terminus contains 1 peptide (amino acids 99-126) of this 126 amino acid prohormone which lower blood pressure and have natriuretic properties. To determine if either the N-terminus and/or the C-terminus of the prohormone have a circadian variation in their circulating plasma concentrations these 8 men had blood samples obtained for radiommunoassay every 3 hr during a 24-hr period. Three radiommunoassays which immunologically recognize (1) the whole N-terminus (i.e. amino acids 1-98), (2) the midportion of the N-terminus (amino acids 31-67) and (3) the C-terminus (amino acids 99-126) of the ANF prohormone were utilized. The whole N-terminus, the midportion of the N-terminus which circulates after being proteolytically cleaved from the rest of the N-terminus, and the C-terminus each had a peak circulating concentration between 0400 and 0700 which were significantly (P less than 0.001) higher than their concentrations at any other time throughout the 24-hr period.(ABSTRACT TRUNCATED AT 250 WORDS)
Vesely
D L
DL
Department of Internal Medicine, University of South Florida for Health Sciences, Tampa.
Kanabrocki
E L
EL
Sothern
R B
RB
Scheving
L E
LE
Tsai
T H
TH
Greco
J
J
Bushell
D L
DL
Kaplan
E
E
Rumbyrt
J
J
Sturtevant
R P
RP
D000328:Adult; D009320:Atrial Natriuretic Factor / Q000097:blood*; D001794:Blood Pressure / Q000502:physiology; D002940:Circadian Rhythm / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010446:Peptide Fragments / Q000097:blood; D011498:Protein Precursors / Q000097:blood*
D010446:Peptide Fragments; D011498:Protein Precursors; C054548:atrial natriuretic factor prohormone (31-67); C055659:atrial natriuretic factor prohormone (1-98); D009320:Atrial Natriuretic Factor