Age-related changes in body fluid volumes in young spontaneously hypertensive rats

Journal Article · Tue Nov 01 00:00:00 EST 1988 · American Journal of Physiology; (USA)

OSTI ID:6289564

Von Dreele, M M ^[1]

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1. Wright State Univ., Dayton, OH (USA)

The authors have measured total body water (TBW, by dessiccation), extracellular fluid volume (ECF, Na{sub 2}{sup 35}SO{sub 4} space), and plasma volume (PV, radioiodinated serum albumin space) in 5-sec-butyl-5-ethyl-2-thiobarbituric acid and sodium salt (Inactin)-anesthetized spontaneously hypertensive (SHR) and Wistar-Kyoto (WKY) rats aged 12-60 days. Interstitial fluid volume (ISF) was calculated as ECF minus PV. Changes in TBW, ECF, and ISF were largely a function of age in both strains, which is typical of developing mammals. Further analysis revealed that although these volumes were significantly larger in SHR before 25 days of age, after 30 days no difference existed between the strains. Before 25 days of age, when SHR's TBW was expanded, no weight difference was seen between the strains. However, once TBW was normalized (after 30 days), WKY was significantly heavier than SHR. The ISF volume was preferentially enlarged in SHR, although PV was also periodically greater. ISF normalized at the time when blood pressure becomes significantly higher in SHR, when plasma aldosterone falls to WKY values in SHR and when renal function is approaching adult levels. Thus the return of ECF (ISF) to normal values may be a result of decreased aldosterone-dependent volume retention or to diuresis induced by increasing blood pressure in an animal whose renal function is close to maturity.

• OSTI ID: 6289564
• Journal Information: American Journal of Physiology; (USA), Vol. 255:5; ISSN 0002-9513
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
BODY FLUIDS
VOLUME
HYPERTENSION
PATHOGENESIS
AGE DEPENDENCE
ALBUMINS
BLOOD PRESSURE
IODINE 125
PHYSIOLOGY
RATS
SODIUM SULFATES
SULFUR 35
ALKALI METAL COMPOUNDS
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BIOLOGICAL MATERIALS
CARDIOVASCULAR DISEASES
DAYS LIVING RADIOISOTOPES
DISEASES
ELECTRON CAPTURE RADIOISOTOPES
EVEN-ODD NUCLEI
INTERMEDIATE MASS NUCLEI
IODINE ISOTOPES
ISOTOPES
LIGHT NUCLEI
MAMMALS
MATERIALS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
PROTEINS
RADIOISOTOPES
RODENTS
SODIUM COMPOUNDS
SULFATES
SULFUR COMPOUNDS
SULFUR ISOTOPES
SYMPTOMS
VASCULAR DISEASES
VERTEBRATES
551001* - Physiological Systems- Tracer Techniques