Modulation of renin secretion by atrial natriuretic factor prohormone fragment 31-67.
BACKGROUND
Earlier studies have indicated that the atrial natriuretic factor prohormone fragment 31-67 (Pro ANF31-67) has important effects for the promotion of sodium excretion and vasodilation in several animal species. However, the mechanisms for the natriuretic actions of Pro ANF31-67 are not completely defined. In the present study, the effects of synthetic Pro ANF31-67 on renin secretion were examined in sodium-depleted, anesthetized dogs with a single intact kidney (n = 5).


METHODS
After 3 20-minute control renal clearance periods, synthetic dog Pro ANF31-67 was given intrarenally at a sustained dose of 0.03 microg/kg/min for 3 20-minute experimental intervals, and after discontinuation of the peptide infusion, 3 final 20-minute recovery periods were determined.


RESULTS
Sustained intrarenal infusions of the Pro ANF31-67 produced striking decrements (p<0.05) in renin secretion, from a control value of 1418 +/- 243 to 401 +/- 223 ng of angiotensin I/min. This 66% fall in renin secretion was associated with significant (P < 0.05) increases in creatinine clearance (40%), renal blood flow (8%), urine flow (50%), and sodium excretion (17%).


CONCLUSIONS
It is suggested that this inhibition of renin secretion was mediated, at least in part, in response to a ProANF31-67-induced increment in the sodium load delivered to the macula densa. An interaction of the peptide with the renal vascular receptor for suppression of renin release is also possible. ProANF31-67 may represent an important hormonal mechanism involved in the regulation of body-fluid balance.
Villarreal
D
D
Department of Internal Medicine, University of Missouri and Harry S Truman VA Hospital, Columbia, USA. daniel_villarreal@health.missouri.edu
Freeman
R H
RH
Taraben
A
A
Reams
G P
GP
D000818:Animals; D009320:Atrial Natriuretic Factor / Q000378:metabolism*; D003404:Creatinine / Q000097:blood; D004231:Diuresis; D004285:Dogs; D005260:Female; D009318:Natriuresis; D010446:Peptide Fragments / Q000378:metabolism*; D011498:Protein Precursors / Q000378:metabolism*; D012079:Renal Circulation; D012083:Renin / Q000378:metabolism*; D014664:Vasodilation
D010446:Peptide Fragments; D011498:Protein Precursors; C054548:atrial natriuretic factor prohormone (31-67); D009320:Atrial Natriuretic Factor; D003404:Creatinine; D012083:Renin