Effect of synthetic ANP on renal and loop of Henle functions in the young rat

Journal Article · Fri Aug 01 04:00:00 EDT 1986 · Am. J. Physiol.; (United States)

OSTI ID:6281159

Roy, D R

The present studies were undertaken to determine, by recollection micropuncture, the effect of a synthetic atrial natriuretic peptide (ANP) on the absolute and fractional deliveries of water and sodium to the juxtamedullary end-descending limb. Two groups of young female Munich-Wistar rats were studied: 1) control received the vehicle only; and 2) ANP received a prime followed by the constant infusion of a synthetic rat atrial peptide (28 amino acids). With the infusion of ANP, clearance of p-( UC)aminohippurate (( UC(PAH) and glomerular filtration rate (GFR) fell significantly. Despite this fall in GFR and renal plasma flow, ANP produced a 2-fold increase in urine volume and a 10-fold increase in sodium excretion. Absolute and fractional sodium deliveries to the end-descending limb increased by approx.30% in the ANP group, whereas mean juxtamedullary single-nephron glomerular filtration rate (SNGFR) remained stable. In three additional rats prepared for micropuncture of the superficial end-accessible proximal tubule, ANP reduced cortical SNGFR by approx.15%. By contrast, GFR did not decline in response to ANP in larger rats, when treated identically. The authors conclude that 1) in young rats ANP can produce a natriuresis in the absence of a rise in GFR; 2) the fall in GFR observed following ANP is due presumably to the immaturity of the animals used in these studies; and 3) ANP produces a rise in absolute and fractional water and sodium deliveries to the end-descending limb that cannot be attributed to a change in SNGFR. The relatively small rise in fractional sodium delivery to the end-descending limb, most probably due to inhibition of sodium and water reabsorption in the juxtamedullary proximal tubule and/or thin descending limb, accounts for only a smallproportion of sodium excretion in the final urine.

• Research Organization: McGill Univ., Montreal, Quebec
• OSTI ID: 6281159
• Journal Information: Am. J. Physiol.; (United States), Journal Name: Am. J. Physiol.; (United States) Vol. 251:2; ISSN AJPHA
• Country of Publication: United States
• Language: English

Related Subjects

551001* -- Physiological Systems-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ABSORPTION
ALKALI METAL COMPOUNDS
AMINO ACIDS
ANIMALS
BIOLOGICAL EFFECTS
BIOLOGICAL FUNCTIONS
BIOLOGICAL MATERIALS
BIOLOGICAL WASTES
BODY
BODY FLUIDS
CARBOHYDRATES
CARBON 14 COMPOUNDS
CARBOXYLIC ACIDS
CHARGED PARTICLES
CLEARANCE
EXCRETION
FUNCTIONS
GLOMERULI
HIPPURIC ACID
HYDROGEN COMPOUNDS
INULIN
IONS
KIDNEYS
LABELLED COMPOUNDS
MAMMALS
MATERIALS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANS
OXYGEN COMPOUNDS
PEPTIDES
PHYSIOLOGY
POLYSACCHARIDES
PROTEINS
RATS
RENAL CLEARANCE
RODENTS
SACCHARIDES
SODIUM COMPOUNDS
TRITIUM COMPOUNDS
URINE
VERTEBRATES
WASTES
WATER