Biomaterial Database

[Effects of fasting on the renal function of rats: Clearance experiments and Henle's loop microperfusion]. 1976

Y Murayama, and S Watanabe, and Y Hayashi

Results of a previous experiment indicated that osmotic pressure and sodium concentration in distal tubular fluid of the nephron constantly microperfused were increased during natriuresis of fasting rats. The present experiments were performed in order to clarify whether or not water reabsorption and urea movement in Henle's loop, which may modify osmotic pressure and sodium concentration in distal fluid, change in the fasting rat kidney. Non-fasting, 18 approximately 24 hours and 4 approximately 5 days-fasting rats were used. After surgical procedures, the animal was infused with 2% saline at 33.3 mul/min. The loop of Henle was perfused with 1% saline containing 0.05% lissamine green, 3H-inulin and 14C-urea at 29.1 nl/min. In the fasting groups, urinary flow and sodium excretion were increased, whereas urea excretion was depressed and inulin clearance showed a tendency to decrease. Tubular fluid to plasma ratio of osmotic pressure in the distal tubule was elevated without change of water reabsorption. From present and previous results, the increases of osmotic pressure and sodium concentration in distal tubular fluid of fasted rat kidney cannot be explained from an increase of water reabsorption in the Henle's loop. Consequently, natriuresis with fasting may contribute partially to an inhibition of sodium reabsorption in Henle's loops, possibly in the thick ascending limbs. Recovery of C-urea perfused into Henle's loops of fasted rats increased.

UI	MeSH Term	Description	Entries
D007668	Kidney	Body organ that filters blood for the secretion of URINE and that regulates ion concentrations.	Kidneys
D007684	Kidney Tubules	Long convoluted tubules in the nephrons. They collect filtrate from blood passing through the KIDNEY GLOMERULUS and process this filtrate into URINE. Each renal tubule consists of a BOWMAN CAPSULE; PROXIMAL KIDNEY TUBULE; LOOP OF HENLE; DISTAL KIDNEY TUBULE; and KIDNEY COLLECTING DUCT leading to the central cavity of the kidney (KIDNEY PELVIS) that connects to the URETER.	Kidney Tubule,Tubule, Kidney,Tubules, Kidney
D008138	Loop of Henle	The U-shaped portion of the renal tubule in the KIDNEY MEDULLA, consisting of a descending limb and an ascending limb. It is situated between the PROXIMAL KIDNEY TUBULE and the DISTAL KIDNEY TUBULE.	Ascending Limb of Loop of Henle,Descending Limb of Loop of Henle,Henle Loop
D009997	Osmotic Pressure	The pressure required to prevent the passage of solvent through a semipermeable membrane that separates a pure solvent from a solution of the solvent and solute or that separates different concentrations of a solution. It is proportional to the osmolality of the solution.	Osmotic Shock,Hypertonic Shock,Hypertonic Stress,Hypotonic Shock,Hypotonic Stress,Osmotic Stress,Hypertonic Shocks,Hypertonic Stresses,Hypotonic Shocks,Hypotonic Stresses,Osmotic Pressures,Osmotic Shocks,Osmotic Stresses,Pressure, Osmotic,Pressures, Osmotic,Shock, Hypertonic,Shock, Hypotonic,Shock, Osmotic,Shocks, Hypertonic,Shocks, Hypotonic,Shocks, Osmotic,Stress, Hypertonic,Stress, Hypotonic,Stress, Osmotic,Stresses, Hypertonic,Stresses, Hypotonic,Stresses, Osmotic
D010477	Perfusion	Treatment process involving the injection of fluid into an organ or tissue.	Perfusions
D011188	Potassium	An element in the alkali group of metals with an atomic symbol K, atomic number 19, and atomic weight 39.10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the WATER-ELECTROLYTE BALANCE.
D005215	Fasting	Abstaining from FOOD.	Hunger Strike,Hunger Strikes,Strike, Hunger,Strikes, Hunger
D005260	Female		Females
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D012964	Sodium	A member of the alkali group of metals. It has the atomic symbol Na, atomic number 11, and atomic weight 23.	Sodium Ion Level,Sodium-23,Ion Level, Sodium,Level, Sodium Ion,Sodium 23